JPH06188008A - Fuel cell - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] To simplify the liquid fuel and oxidant gas supply system, simplify the structure, maintain high efficiency, and downsize. A fuel cell using a liquid fuel as a fuel, comprising a stack 6 in which a plurality of electromotive parts 4 each having a fuel electrode 2, an oxidizer electrode 3 and an electrolyte layer sandwiched between these two electrodes 2 and 3 are laminated. Among the outer peripheral surfaces of the stack 6, along the at least one surface including the end surface of the fuel electrode and arranged in parallel with the flow of the oxidant gas flowing in the vertical direction, the flow may be orthogonal to the flow of the oxidant gas. Direction, a fuel cell in which a liquid fuel introduction path in which the liquid fuel directly contacts the end surface of the components of the electromotive section 4 is provided, and the liquid fuel in the liquid fuel introduction path is supplied to the fuel electrode by a capillary force.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a fuel cell, and more particularly to a fuel cell suitable for miniaturization.

[0002]

2. Description of the Related Art Fuel cells have recently been attracting attention because they are efficient as a single power generator. Fuel cells include phosphoric acid fuel cells that use gas as fuel, molten carbonate fuel cells, solid electrolyte fuel cells, alkaline electrolyte fuel cells, and methanol fuel cells that use liquid as fuel. It is roughly divided into hydrazine fuel cells and the like. Since these fuel cells are mainly targeted at power sources for operating electric power generators and large equipment, compressors, pumps, etc. for introducing gas or liquid fuel or oxidant gas into the cells. Are required and are not only complex as a system, but also consume power for their implementation.

Taking a methanol fuel cell using methanol as a liquid fuel as an example, in a methanol fuel cell system, fuel is sent from a methanol tank to a cell body by a pump, and air, which is an oxidant, is fed to the cell body by a blower. Sent to. In particular, in this battery, a mixed liquid of methanol as a fuel and electrolyte, for example, dilute sulfuric acid as a dissolved fuel is pumped to the battery main body by a pump through a methanol controller or an acid controller, so that the system is more complicated. It has become. This complexity is similar for other fuel cells, and any system requires a blower or pump to deliver fuel or oxidant gas. The complexity of such a system is because current fuel cells are targeted for large amounts of electric power, such as for electric power and as a power source for large equipment.To achieve this, a large amount of fuel and oxidizer are used. Gas must be passed, and therefore a pump, blower, etc. are required.

On the other hand, as a social trend, various kinds of equipment such as OA equipment, audio equipment, and radio equipment have been miniaturized with the development of semiconductor technology, and further required to be portable. A simple primary battery, a secondary battery, or the like is used as a power source for satisfying such requirements. However, the primary battery and the secondary battery are functionally limited in usage time, and naturally the usage time is limited in an OA device or the like using such a battery. When using these batteries, after the batteries are discharged, the batteries can be replaced and OA devices etc. can be operated, but with primary batteries, the usage time is short relative to the weight and it becomes a portable device. Is not suitable for.
In addition, a secondary battery can be charged when it is completely discharged, but on the other hand, it requires a power source for charging, which limits the place of use and also has the drawback that it takes time to charge. In particular, in an OA device or the like incorporating a secondary battery, it is difficult to replace the battery even after the battery has been discharged, and thus the operating time of the device cannot be limited. As described above, in order to operate various small devices for a long time, it is difficult to extend the conventional primary battery or secondary battery, and a battery suitable for a longer operation is required.

As one solution to such a problem, there is a fuel cell as described above. Fuel cells not only have the advantage that they can generate electricity simply by supplying the fuel and oxidant, but also have the advantage that they can generate electricity continuously if the fuel is exchanged. It can be said that this system is extremely advantageous for the operation of small equipment such as OA equipment with low electric power.

Since air can be used as an oxidant in a fuel cell, there is no restriction on the place of use or the time of use from the viewpoint of the oxidant. However, when gas is used as the fuel, it can be used in OA equipment or the like. Although the power consumption is small, considering the gas density, the amount of gas required for power generation is large, and it is not suitable for downsizing batteries. On the other hand, liquid fuel has a higher density than gas, and is overwhelmingly advantageous as a fuel for fuel cells for small devices. Therefore, if the fuel cell using the liquid fuel can be miniaturized, it is possible to realize a power source for a compact device that can operate for a long time, which has not been achieved in the past. As described above, the obstacle to realizing the power supply for such a compact device is that, in the system using the conventional liquid fuel, the pump for feeding the liquid fuel into the cell body and the oxidant gas for feeding the liquid fuel. Since it requires a blower etc., the system is complicated, and it is difficult to downsize it with this structure.

Further, in conventional fuel cells such as phosphoric acid fuel cells, molten carbonate fuel cells, and solid oxide fuel cells, the gas supplied to the cells by a pump or a blower is an oxidizer electrode and a fuel. It is introduced into each electrode through a gas channel provided adjacent to the pole. In this case, from the viewpoint of flowing a large amount of fuel gas and oxidant gas so as not to give a load to the pump and the blower, the gas channel of the gas channel has a large groove shape so that pressure loss is not generated as much as possible. For example, in a molten carbonate fuel cell gas channel, a groove having a depth of more than 2 mm is usually formed. This is the same in a fuel cell using a liquid fuel such as a methanol fuel cell, and in particular, in a methanol fuel cell, unlike the above-mentioned phosphoric acid fuel cell, etc., an electrolyte such as sulfuric acid is used in the electrolyte layer and the fuel electrode. Since a mixture of methanol and methanol as a fuel flows, the pressure loss becomes larger than that when gas is used as a fuel. As described above, in the conventional fuel cell, in order to feed gas or liquid with a pump or a blower, the groove shape of the gas channel must be increased. Conversely, if the groove shape is decreased, the pump and the blower become large. There is a problem that miniaturization cannot be achieved by extending the technology so far.

A liquid fuel cell (see Japanese Patent Laid-Open No. 59-66066) that utilizes capillary force to supply liquid fuel is proposed as a fuel cell that addresses the above-mentioned points and responds to miniaturization. Has been done. This liquid fuel cell uses the capillary force of organic or inorganic fiber materials such as paper, cotton, asbestos, glass, etc., and capillary materials based on synthetic fibers such as acrylic, nylon etc. It is a parallel-flow type cell that sucks up one direction from the chamber to supply it to the anode and causes the oxidant gas to flow in the same direction as the fuel supply direction. In this cell, the fuel storage chamber is provided in the lower portion, and a gas inlet is required in the lower portion of the cell in order to flow the oxidant gas in the vertical direction. Therefore, a gap is provided between the fuel storage chamber and the bottom surface of the stack. It has a structure provided. Further, in this system, the constituent material is made of the flexible fiber as described above so that the supply of fuel can be controlled by mechanically squeezing a part of the capillary material. Furthermore, this battery has a structure in which the capillary material made of the electrically insulating material as described above is embedded in a part of the anode side current collector so as to be in close contact with the current collector.

The above-mentioned liquid fuel cell is suitable for downsizing as compared with the conventional fuel cell because the liquid fuel is supplied to the fuel electrode by the capillary force, but it has a plurality of problems, and improvements thereof are demanded. There is. For example, as described in the above publication, liquid fuel permeates or permeates in the anode (fuel electrode) in the horizontal direction, but has a structural restriction that it does not exhibit a capillary action in the upward direction. .
Further, as described above, in this type of battery, a gap is required between the bottom surface of the stack and the fuel storage chamber, and since the fibrous capillary material is inserted into the fuel storage section, the capillary material and the fuel storage chamber are inserted. It becomes difficult to seal the fuel tank and the fuel tank, and the stack and the fuel storage chamber must be integrally fixed. In addition, in the case of integration, a plurality of inlets for introducing the capillary material must be provided at the upper part of the fuel storage chamber, which not only complicates the structure but also has a drawback that the manufacturing thereof is extremely difficult. Moreover, in this fixed structure, it is necessary to make a slit at least in the oxidant electrode portion on the bottom surface of the stack in order to flow the oxidant, which also complicates the structure.

Further, since the liquid fuel is supplied from the lower part to the upper part by a unidirectional capillary action as described above, it takes a long time to supply the fuel to the upper part of the fuel electrode and the shape of the cell is changed. You will be constrained. That is, in order to increase the current, it is necessary to increase the area of the electromotive components such as electrodes and electrolyte plates, but if there is a limit to the height as in this method, increase the width of the electromotive components. Inevitably,
There are restrictions on the battery shape. Further, in this battery, the insulating capillary material is embedded in a part of the current collector on the fuel electrode side, so that the electrons obtained as a result of the cell reaction have no choice but to flow through the current collector. In addition to being concentrated, there is a drawback that the path of electricity flow becomes long and electrical loss occurs.

On the other hand, regarding the tightening of the battery, in the conventional high output and large area fuel cell, a large tightening device to which uniform force is applied is used in order to improve the performance by improving the contact between the cell parts. Was there. For example, the cell area of a commercial phosphoric acid type fuel cell or a molten carbonate type fuel cell is about 5000 to 10000 cm ² , and in order to tighten this so that the contact between parts is good, it is about 15 to 30 tons.
Must be tightened with a device having a tightening load of. Therefore, all the tightening devices used in the conventional fuel cells are complicated and large-scale devices, and are not suitable for the fuel cells that are to be downsized.

On the other hand, one of the factors that complicate the conventional fuel cell system is the problem of removing water formed as a reaction product on the electrode surface. In a fuel cell, water is generated as a product of an electrode reaction at one electrode, and this water needs to be removed from the electrode surface. The retention of the product on the surface of the electrode hinders the supply of the substance to be replenished, and as a result, reduces the reaction efficiency.

In particular, a solid polymer electrolyte fuel cell using a proton conductive membrane such as perfluorocarbon sulfonic acid (trade name: manufactured by Nafion: Du Pont) as an electrolyte has a relatively low temperature (room temperature to 100 ° C.). Since it operates, it can be expected as a power source for small equipment.
In a fuel cell that operates at a low temperature of ℃ or less, water generated at the oxidizer electrode is generated in a liquid state, so that it is difficult to volatilize and the problem of water retention on the electrode surface becomes more serious.

In the conventional fuel cell, an air supply duct is provided on the side surface of the cell body, an air exhaust duct is arranged on the opposite surface, and the produced water is condensed on the wall surface of the air exhaust duct to recover the produced water. Was there. FIG. 42 shows a schematic diagram of a conventional fuel cell.

That is, as shown in FIG. 42, on the side surface of the fuel cell body 81, an air supply duct 83 to which a blower 82 is attached and an air exhaust duct 84 on the opposite side are installed, and below this air exhaust duct 84. Generated water recovery duct 5
4 are provided, and these are housed in the battery case 57 in which the air inlet 86 and the air outlet 87 are opened. The air is supplied by the blower 82, the air containing the generated water is sent into the air exhaust duct 84, the generated water is condensed on the inner wall surface of the air exhaust duct 84, and the condensed generated water is generated in the lower part. The collected air is collected in the water collecting tank 85, and the discharged air is discharged to the outside through the air outlet 87.

When the above-described method of recovering produced water is applied to an expected small-sized fuel cell, the driving power of the blower itself and the volume of the blower cannot be ignored, resulting in high charging efficiency and small size. Loses its strengths. Although other methods of recovering the generated water have been proposed, the method of once vaporizing the generated water needs to supply energy equivalent to the heat of vaporization, and in principle energy efficiency is not improved.

Therefore, in order to realize a small-sized fuel cell, a mechanism for removing water generated from the oxidizer electrode without using special power or energy is required.

On the other hand, another factor that complicates the fuel cell system is its structural problem.

FIG. 43 shows a general laminated structure of a phosphoric acid fuel cell as an example. In this case, a conductive plate 39 called a separator or interconnector is provided between the electromotive parts including the oxidizer electrode 38, the electrolyte layer 36, and the fuel electrode 37.
, Which connects each electromotive section in series to secure the required voltage. This structure is applied not only to the phosphoric acid type fuel cell but also to a molten carbonate type fuel cell, a solid polymer electrolyte type fuel cell and the like. In the fuel cell having such a structure, the fuel or air as an oxidant supplied to the cell by using a pump, a blower or the like passes through each electrode through an oxidizer electrode plate and a separator provided adjacent to the fuel electrode plate. Will be introduced to. In this case, from the viewpoint of flowing a large amount of fuel and reactants such as oxidant gas without giving a load to the pump or blower, the gas flow path of the separator or electrode plate should have a certain depth so that pressure loss does not occur as much as possible. Is formed into a groove shape. In particular, when a liquid fuel such as methanol is used, unlike the phosphoric acid fuel cell described above, a liquid fuel is flown, so that the pressure loss becomes a larger value than when gas is used as the fuel.

As described above, in the fuel cell having the conventional structure, it is necessary to form a groove or the like in the separator or the like as the flow path of the reactant, so that a certain thickness is required, and the fuel cell and the electrolyte layer which is the original power generation section are required. There is no choice but to increase the volume occupied by the fuel and the oxidizer electrode other than the reaction catalyst and the current collector. Even if the electrode plate or the separator acting as a flow path is made thin and small, in this case, the pump, blower, etc. are burdened to supply the reactant through the narrow flow path, and the mechanism must be enlarged. Absent.

From the above, a measure for reducing the size of the entire fuel cell by suppressing the volume occupied by the electrolyte layer, which is the original electromotive portion, and the reaction electrode and the current collector of the fuel electrode and the oxidant electrode, as small as possible. As a method, for example, a method of arranging a plurality of electromotive portions vertically in the thickness direction, that is, side by side, and connecting them in series at their ends can be considered. In this case, not only the reactants can be supplied and the products can be collected from one space for a plurality of electromotive parts, but also a separator is not required, and the electrode plate also has a function as a flow path. Since it is not necessary, it can be omitted or thinned. Such an idea has already been disclosed in JP-A-63-14126.
No. 6 and Japanese Patent Laid-Open No. 63-141270.

However, the fuel cell having such a structure has the following problems.

In a normal fuel cell, the same kind of electrolyte or water vapor as that contained in the electrolyte layer is added to the reactants supplied in order to compensate the outflow / evaporation of the components in the electrolyte from the electrolyte layer or to prevent the components from drying. It is mixed.

Among them, a solid polymer electrolyte fuel cell using a proton conductive membrane or the like such as the above-mentioned perfluorocarbon sulfonic acid (trade name: manufactured by Nafion Du Pont) is used as an oxidizer from the fuel electrode during operation. Since water flows along with the ions to the pole, the water content on the fuel electrode side gradually becomes insufficient,
Efficiency is reduced. Therefore, in the fuel supplied to the fuel electrode, liquid electrolyte such as methanol is mixed with liquid electrolyte, and hydrogen gas is mixed with water vapor.

On the other hand, water is produced at the other electrode. In the above-mentioned polymer electrolyte fuel cell, water is excessive on the oxidant electrode side because there is water generated from the electrode reaction and water flowing from the fuel electrode.

The water or electrolyte mixed with such a reactant and supplied, or the generated water ionically couples and short-circuits a plurality of power generating elements, which causes a drop in battery voltage. Especially, when the water or the electrolyte is present in a liquid state, the problem is remarkable.

As described above, a fuel cell having a structure in which a plurality of power generating elements are arranged side by side and the ends thereof are connected in series shares a fuel supply space and a product recovery space, and the distance between electrodes is Due to the short length, the problem of such voltage loss is more serious.

FIG. 28 is a schematic view showing a case where two power generating units are arranged side by side and connected in series. In FIG. 28, 37 is a fuel electrode, 60 is an electrolyte layer, 38 is an oxidizer electrode, and two electromotive parts 55 are electrically connected in series by a lead 57. Fuel electrodes 37a, 3 of the two power generation units
7b and the oxidizer poles are next to each other. Both fuel supply and product discharge can be performed from one space in both power generation units. In FIG. 28, the fuel is supplied from the fuel flow path 58 and the oxidant gas is supplied from the oxidant flow path 59.

In this case, the fuel electrode 37a of one power generation section
And the fuel electrode 37 having the same potential as the oxidizer electrode 38a of this power generation unit
A potential gradient is generated between b and b. Also oxidizer pole 3
Similarly, a potential gradient is generated between 8a and the oxidant electrode 38b.

At this time, the surfaces of both electromotive parts, that is, the fuel flow path 5
8. If there is a substance acting as an electrolyte in the oxidant flow channel 39, the ions move according to the above-mentioned potential gradient, which acts as a leakage current to cause a voltage loss.

Therefore, as described above, when a plurality of power generating units are arranged side by side in series and the fuel supply space and the product recovery space are common, the size of the fuel cell can be reduced. Since the efficiency of the battery decreases due to the voltage loss that occurs between the power generation units, it is necessary to reduce such voltage loss.

On the other hand, generally, the fuel supplied to the fuel cell is a gas such as hydrogen gas or a liquid such as methanol or hydrazine. When gas is used as the fuel, although the power consumption of OA equipment and the like is small, the amount of gas required for power generation is large in view of the density of the gas, which is not suitable for downsizing the battery. On the other hand, liquid fuel has a higher density than gas, and is overwhelmingly advantageous as a fuel for fuel cells for small devices. Therefore, if the fuel cell using the liquid fuel can be miniaturized, it is possible to realize a power source for a compact device which can be operated for a long time, which has never been achieved.

Among the liquid fuels, C1 to C2 compounds such as methanol and ethanol are inexpensive and have appropriately high boiling points, so that they can be easily used from the viewpoint of safety. However, a technical difficulty in such a battery is the development of an electrode catalyst. That is, in the anodic oxidation of a fuel containing carbon such as methanol, even with platinum having a high catalytic activity, a poisoning phenomenon occurs in which an intermediate product of the reaction is strongly adsorbed on the electrode surface with the passage of time, resulting in a large catalytic activity. Is a serious problem for practical use.

Therefore, an electrode catalyst having excellent resistance to poisoning has been studied, but sufficient characteristics have not yet been obtained. Therefore, a fuel cell capable of stably obtaining a high output for a long time has not yet been obtained. Therefore, in the case of a fuel cell using an organic fuel such as methanol, it is necessary to suppress the poisoning phenomenon on the electrode surface.

As described above, a general conventional fuel cell has a problem that the system is complicated and it is difficult to reduce the size of the fuel cell as it is. On the other hand, although the conventional liquid fuel cell utilizing capillary force is suitable for downsizing in the structure, it has a complicated structure and many structural restrictions, so that it can be downsized, for example, as a power source for small devices. Has not been achieved. Further, regarding the tightening method of the cell parts, the discharge of the generated water, the connection between the electromotive parts, etc., it is required to cope with the downsizing of the fuel cell. Furthermore, when liquid fuel is used, it is required to deal with poisoning on the electrode surface.

[0036]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems in the conventional fuel cell described above and to provide a small fuel cell useful as a power source for small equipment. The first is to provide a fuel cell that simplifies the supply system of liquid fuel and oxidant gas and simplifies the structure to enable miniaturization while maintaining high efficiency. is there.

A second object is to provide a fuel cell suitable for miniaturization by discharging water generated by the operation of the fuel cell without using special power or energy. Further, the third object is to suppress the ionic conduction between the electromotive parts to a minimum and to make the fuel cell suitable for miniaturization of the fuel cell. Even if the electromotive parts are connected to each other, the voltage loss is small and the fuel cell is suitable for practical use. To provide. Further, a fourth object is to suppress the poisoning phenomenon occurring on the electrode surface and obtain a stable output for a long time when a liquid organic fuel such as methanol, which is suitable as a fuel used for a small-sized fuel cell, is used. To provide.

[0038]

The present invention has been made in order to achieve the above-mentioned object. The first object of the present invention is to simplify the raw material supply system. A stack of a plurality of electromotive parts each having an electrode, an oxidizer electrode and an electrolyte plate sandwiched between these electrodes, liquid fuel is used as the fuel, and the oxidizer gas is perpendicular to the stack surface of the stack. In a fuel cell configured to flow in a direction, in the outer peripheral surface of the stack,
The end face of the fuel electrode is formed on the end face of the fuel electrode in a direction orthogonal to the flow of the oxidant gas along at least one face including the end face of the fuel electrode and arranged in parallel with the flow of the oxidant gas. It is characterized in that a liquid fuel introduction passage is provided in direct contact with the liquid fuel, and the liquid fuel is supplied to the fuel electrode by a capillary force.

The second fuel cell has a stack in which a plurality of electromotive portions having a fuel electrode, an oxidizer electrode, and an electrolyte plate sandwiched between the electrodes are laminated with a separator interposed therebetween, and a liquid fuel is used as the fuel. A fuel cell configured to flow an oxidant gas in a vertical direction along a stacking surface of the stack, wherein an oxidant gas supply groove that causes the oxidant gas to flow in a vertical direction is provided on a surface of the separator in contact with the oxidant electrode. And at least one of the outer peripheral surfaces of the stack, which includes the end surface of the fuel electrode and is arranged parallel to the flow of the oxidant gas, is orthogonal to the flow of the oxidant gas. In such a direction that a liquid fuel introduction path is provided in which the liquid fuel is in direct contact with the end surface of the fuel electrode, and the oxidant gas is supplied through the oxidant gas supply groove while the liquid fuel is supplied. Serial capillary force of the porous body that becomes the fuel electrode is characterized by being configured to supply to the fuel electrode.

Further, the third fuel cell comprises a stack in which a plurality of electromotive parts having a fuel electrode, an oxidizer electrode and an electrolyte plate sandwiched between both electrodes are laminated via a separator,
A liquid fuel is used as a fuel, and in a fuel cell configured to flow an oxidant gas in a vertical direction along a stacking surface of the stack, the oxidant gas is applied in a vertical direction to a surface of the separator in contact with the oxidant electrode. A groove for supplying an oxidant gas flowing through the stack, and along the at least one surface of the outer peripheral surface of the stack that includes the end surface of the fuel electrode and is arranged in parallel with the flow of the oxidant gas. A liquid fuel introduction passage is provided in a direction orthogonal to the flow of the oxidant gas, and a liquid fuel supply groove having one end opened toward the liquid fuel introduction passage is provided on a surface of the separator in contact with the fuel electrode. The oxidant gas is supplied through the oxidant gas supply groove, and the liquid fuel is supplied to the fuel electrode at least by the capillary force of the liquid fuel supply groove. It is characterized.

Furthermore, the fourth fuel cell has a fuel electrode,
The stack comprises a stack of a plurality of electromotive parts each having an oxidizer electrode and an electrolyte plate sandwiched between these electrodes, liquid fuel is used as the fuel, and the oxidizer gas is vertically applied along the stack surface of the stack. In a fuel cell configured to flow, an oxidant gas supply groove for flowing the oxidant gas in a vertical direction is provided on a surface of the fuel electrode in contact with the oxidant electrode, and the fuel is included in an outer peripheral surface of the stack. The liquid fuel is applied to the end surface of the fuel electrode along at least one surface including the end surface of the electrode and arranged in parallel with the flow of the oxidant gas, in a direction orthogonal to the flow of the oxidant gas. Is provided in direct contact with the liquid fuel introduction path, while supplying the oxidant gas through the oxidant gas supply groove,
By the capillary force of the porous body that becomes the fuel electrode, the liquid fuel,
It is characterized in that it is configured to supply to the fuel electrode.

Furthermore, the fifth fuel cell has a fuel electrode,
The stack comprises a stack of a plurality of electromotive parts each having an oxidizer electrode and an electrolyte plate sandwiched between these electrodes, liquid fuel is used as the fuel, and the oxidizer gas is vertically applied along the stack surface of the stack. In the fuel cell configured to flow, the oxidant electrode is provided with an oxidant gas supply groove that causes the oxidant gas to flow in a vertical direction, and the outer peripheral surface of the stack includes an end surface of the fuel electrode, and A liquid fuel introduction path in which the liquid fuel is in direct contact with the end surface of the fuel electrode in a direction orthogonal to the flow of the oxidant gas along at least one surface arranged in parallel with the flow of the oxidant gas. Is provided, and the oxidant gas is supplied through the oxidant gas supply groove, and the liquid fuel is supplied to the fuel electrode by the capillary force of the porous body serving as the fuel electrode. It is.

Furthermore, the sixth fuel cell has a fuel electrode,
In a fuel cell comprising a stack of a plurality of electromotive parts having an oxidizer electrode and an electrolyte plate sandwiched between these electrodes, the stack is clamped with a material exhibiting rubber elasticity at least in the stacking direction. Is characterized by.

In the above fuel cell of the present invention, since the oxidant gas is first made to flow in the direction perpendicular to the stack, the oxidant gas can be effectively flowed. Further, the liquid fuel introduction path is provided along the outer peripheral surface of the stack arranged in parallel with the flow of the oxidant gas in a direction orthogonal to the flow of the oxidant gas, and introduced into the liquid fuel introduction path. Since the liquid fuel is configured to be supplied to the fuel electrode by the capillary force, it is possible to reliably supply the liquid fuel by the capillary force without hindering the flow of the oxidant gas.
In addition, the structure can be simplified and there are few restrictions on the configuration. As a result, the oxidant gas and the liquid fuel can be smoothly supplied without using auxiliary parts such as a pump and a blower, so that the size can be reduced.

A fuel cell having an improved method of discharging produced water, which is a second object of the present application, has the following constitution.

That is, a fuel electrode, an oxidizer electrode, and a power generation section having an electrolyte layer sandwiched between these electrodes, and a first electrode provided in contact with the oxidizer electrode and absorbing water generated from the oxidizer electrode. The porous body and the second porous body, which is provided in contact with the first porous body and absorbs water held by the first porous body, are configured such that the average pore diameter decreases along the direction of water flow. It is a fuel cell characterized in that

For example, in a fuel cell using a liquid fuel such as methanol, the following mechanism operates as a fuel cell.

Fuel such as methanol is supplied to the fuel electrode,
Oxygen is supplied to the oxidizer electrode. Taking methanol as an example, the following reaction occurs.

Fuel electrode (anode): CH ₃ OH + H ₂ O
→ CO ₂ +6 H ₊ +6 e Oxidizer electrode (cathode): 3 / 2O ₂ +6 H ⁺ +6 e →
3 H ₂ O total reaction: CH ₃ OH + 3 / 2O ₂ → CO ₂ +2 H 2 O That is, methanol reacts with water equimolar in the fuel electrode,
Carbon dioxide gas and protons are generated, and the protons pass through the solid polymer electrolyte membrane and react with oxygen at the fuel electrode to produce 3 mol of water. In total, methanol reacts with oxygen to produce 2 moles of water. In order to smoothly carry out such a reaction, it is necessary to promptly remove at least the produced water.

When a power source for small equipment is assumed,
You need to do this without any extra power.

Therefore, in the present invention, the structure of the oxidizer electrode is such that the porous body is provided so as to contact the surface of the oxidizer electrode, or the oxidizer electrode itself is made into a porous body, and the oxidizer electrode is formed by the action of the capillary phenomenon of the porous body. Absorb the resulting water. Further, the water is recovered by oxidizing a porous body having a capillary force stronger than that of the porous body provided so as to be in contact with the surface of the oxidant electrode or the oxidant electrode itself composed of the porous body, that is, a porous body having an average pore diameter smaller than that of the porous body. It is brought into contact with a porous body provided so as to contact the surface of the agent electrode or an oxidant made of a porous body. As a result, water is smoothly removed from the oxidizer electrode surface.

The present invention is particularly effective when applied to a fuel cell which operates at a temperature at which water produced at the oxidizer electrode is liquid, that is, at a temperature of about 100 ° C. or lower. That is, this is because the absorption of water by the capillary phenomenon of the porous body effectively acts when the water is a liquid.

Examples of fuel cells having an operating temperature of about 100 ° C. or lower include alkaline fuel cells, phosphoric acid fuel cells under special operating conditions, and solid polymer electrolyte fuel cells. In particular, the solid polymer electrolyte used in the solid polymer electrolyte fuel cell is composed of a polymer compound having an ion-exchange ability, and the one formed in the form of a membrane has no loss of electrolyte solution and is a reactant of the anode and cathode. Is prevented from mixing
It is suitable for downsizing and simplification of fuel cell systems. At present, a proton conductive solid polymer membrane is put into practical use, but an anion conductive membrane may be used.

In consideration of downsizing of the fuel cell,
Hydrogen gas or the like can be used as the fuel. For example, hydrogen gas stored in a hydrogen storage alloy may be used. However, it is practically preferable to use alcohols such as methanol and ethanol, which are liquid at room temperature, or fuel such as hydrazine or amine acid.

The third object of the present application, the fuel cell with less voltage loss between the electromotive sections, has the following configuration.
That is, a fuel electrode, an oxidizer electrode, and an electromotive portion having an electrolyte layer sandwiched between these electrodes are provided, a plurality of electromotive portions are connected in series, and the fuel electrode of each electromotive portion has a common fuel flow path. Fuel is supplied from the electromotive section and the electrode surface of the fuel electrode of each electromotive section faces the fuel channel, or the oxidant electrode of each electromotive section is supplied with the oxidant from a common oxidant channel. In the fuel cell having a structure in which the electrode surface of the oxidizer electrode of each electromotive section faces the oxidizer channel, the electrolyte layer contains a water-absorbing or water-retaining substance. To do.

That is, in the above fuel cell, in addition to the compound having an ion-exchange ability which is a main constituent of an ordinary electrolyte as the electrolyte layer of the electromotive section, water is supplied / retained inside the membrane or the concentration thereof is increased. A substance in which a water-absorbing or water-retaining substance capable of passing water according to a gradient is coexistent is used.

As described above, the electrolyte layer according to the present invention exhibits water absorption or water retention by itself, so that water generated on one electrode catalyst surface can be quickly absorbed and the catalyst surface can be always brought into contact with the reactive substance. While being kept, the absorbed water diffuses in the electrolyte according to a concentration gradient, and also functions to prevent the other electrode surface from drying. Further, in this process, the electrolyte itself also exhibits excellent properties such that effective ion dissociation and ion conduction characteristics can be always maintained without addition of moisture from the outside.

Therefore, in the fuel layer using this electrolyte layer, water can be supplied into the electrolyte without mixing water in the reactant to be supplied, and the water generated in the oxidizer electrode is promptly absorbed. Therefore, it is possible to suppress the ion conduction in the areas other than the electrolyte layer to be small.

Examples of the water-absorbing or water-retaining substance according to the present invention include starch, acrylonitrile copolymer, water-absorbing polymer compounds such as cross-linked acrylate and cross-linked polyethylene oxide, silica hydrogel, denatured protein (gelatin) gel. Compounds and the like can be used.

Further, as the electrolyte, the remarkable effect of the present invention can be obtained in the case of a solid polymer electrolyte. Examples of the solid polymer electrolyte include a proton conductive solid polymer electrolyte and a polystyrene cation exchange membrane having a perfluorocarbon sulfonic acid polymer (trade name: Nafion (manufactured by Du Pont, USA) sulfonic acid group.

By using such an electromotive unit, no substance unavoidably mixed with the substance acting as an electrolyte is contained in any of the reactants supplied to the oxidizer electrode and the fuel electrode, which are the essence of the present invention. Further, it is possible to realize a fuel cell having a configuration in which the ends of a plurality of electromotive sections are connected in series with each other.

Next, as a method of connecting the ends of a plurality of power generating elements in series with each other, a method of directly connecting the current collector of each power generating element by welding, a conductive adhesive or the like, mixing of reactants and leakage current In order to prevent this, a method of connecting via a conductive plate or the like, or a method of integrally manufacturing a plurality of power generation units so as to be connected in series in advance when manufacturing the power generation unit can be adopted.

Further, in these methods, it is also effective to subject the connecting portions of a plurality of electromotive portions to water repellent treatment in order to suppress electrolyte leakage.

Next, the fourth object of the present application is to provide a fuel cell for suppressing the poisoning phenomenon occurring on the surface of an electrode in a fuel cell provided with a fuel electrode, an oxidant electrode and an electrolyte layer sandwiched between these electrodes. It is characterized by having a mechanism for anodically polarizing the fuel electrode.

That is, in the present invention, when a poisoning product on the surface of the fuel electrode is generated during the operation of the fuel cell, the counter electrode is connected to the fuel electrode and anodically polarized to remove the poisoning product by oxidation. To do. As a result, a fuel cell that can obtain a stable output for a long time can be obtained.

Further, in a normal fuel cell, the fuel electrode,
A plurality of electromotive parts composed of an oxidizer electrode and an electrolyte are connected in series and used. In this case, the polarization operation is preferably performed as rotation for each electromotive section.
As a result, poisoning products can be removed without interrupting the operation.

[0067]

Embodiments of the present invention will be described below.
First, a fuel cell that has been downsized while maintaining high efficiency by simplifying the liquid fuel and oxidant gas supply system and the structure, which is the first object of the present application, will be described.

FIG. 1 is a partially cutaway perspective view showing the structure of the main part of a fuel cell according to one embodiment. In FIG. 1, reference numeral 1 is an electrolyte plate sandwiched by a fuel electrode (anode) 2 and an oxidant electrode (cathode) 3, and the electromotive portion 4 is constituted by the electrolyte plate 1, the fuel electrode 2 and the oxidant electrode 3. Has been done. Here, the fuel electrode 2 and the oxidant electrode 3 are formed of a conductive porous body so that the fuel and the oxidant gas may flow and electrons may pass therethrough.

By stacking a plurality of the electromotive sections 4 as described above with the separator 5 in between, a stack 6 which is a battery body is formed. The stack 6 is basically installed so that the laminated surface of the electromotive section 4 is parallel to the vertical direction. Since the separator 5 also functions as a current collector plate that conducts generated electrons, it is made of a conductive material. If necessary, fuel electrode 2
A layered, island-shaped, or granular catalyst layer may be formed between the oxidant electrode 3 and the electrolyte plate 1, but the present invention is not limited by the presence or absence of such a catalyst layer. .
Further, the fuel electrode 2 and the oxidant electrode 3 themselves may be used as the catalyst electrode.

Here, in the fuel cell of the present invention, in order to effectively flow the oxidant gas, for example, air without requiring power, a structure in which the oxidant gas flows vertically to the stack 6 is adopted. There is a need to. In particular, by flowing the oxidant gas from the bottom to the top of the stack 6,
The heat generated as a result of the cell reaction causes the oxidant gas to flow extremely smoothly. So, in this example,
On the surface of the separator 5 in contact with the oxidant electrode 3, an oxidant gas supply groove 7 for flowing the oxidant gas in the vertical direction (z direction in the drawing) is provided as a continuous groove.

Further, since the density of gas is significantly smaller than that of liquid, considering the balance between the liquid fuel and the oxidant gas necessary for the cell reaction, the structure should be such that the supply of the oxidant gas is increased rather than the supply of the liquid fuel. Is advantageous for efficiency, performance, and further miniaturization of the battery. From this viewpoint, the larger the cross-sectional area of the oxidant gas supply groove 7, the more advantageous it becomes.
If the groove width is made too large to increase the groove cross-sectional area,
If the electrical contact area becomes small and loss occurs, and if the depth is made too deep, the electrode thickness or the separator 5 becomes thick, which is disadvantageous for downsizing. Further, if the cross-sectional area of the groove is reduced and the number of grooves is increased, the pressure loss of the oxidant gas in the gas supply groove 7 increases and it becomes difficult to smoothly flow the oxidant gas. Therefore, the width of the groove 7 is about 0.5 to 20 mm, and the depth of the groove 7 is 0.2 mm.
It is preferably about 2 mm. The shapes of these oxidant gas supply grooves 7 are determined in consideration of the fuel gas supply method described later.

As described above, the separator 5 in this embodiment also has a function as a channel for flowing the oxidizing gas. As described above, by using the component 5 having both the functions of the separator and the channel (hereinafter referred to as the channel-cum-separator), the number of components can be further reduced, and the size can be further reduced. . It is also possible to use a normal channel instead of the separator 5.

The channel / separator 5 as described above may be formed of a metal plate having no holes, or may be a porous body, as long as it can separate the liquid fuel and the oxidant gas. Good. When a porous body is used, at least one of the fuel electrode side surface and the oxidant electrode side surface of the channel / cum-separator 5 may be closed so that the liquid fuel does not enter the oxidant electrode 3. preferable. Further, in order to improve the flow of the oxidant gas, the pore diameter of the channel / separator 5 made of a porous material is set to the oxidant electrode 3
It is preferable to set the diameter larger than the pore diameter of the porous body.

Further, the shape of the oxidant gas supply groove 7 is not particularly limited as long as it satisfies the above-mentioned conditions. For example, as shown in FIG. 2, a thin metal plate is pressed or rolled. It is also possible to use the channel-combined separator 8 which is bent by. In such a separator 8, the oxidant gas supply groove 7 is provided on the oxidant electrode 3 side, and the continuous groove 9 can be provided on the fuel electrode 2 side. Further, it is possible to provide the oxidant gas supply groove 7 in the channel / separator 5 (8) and also provide the oxidant electrode 3 with a groove for flowing the oxidant gas in the vertical direction.

At least one side surface of the above-mentioned stack 6 is provided with a fuel introduction passage constituting member 11 so that the liquid fuel introduction passage 10 is formed along this surface.
Then, the liquid fuel (usually a mixed liquid of electrolyte, for example, dilute sulfuric acid and methanol that serves as a fuel) introduced into the liquid fuel introducing passage 10 is supplied to the fuel electrode 2 from the side surface of the stack 6 by a capillary force. It Here, when the liquid fuel introduction passage 10 is provided in the upper part or the lower part of the stack 6 when the oxidant gas flows from the lower part to the upper part, the structure of the stack 6 becomes extremely complicated. Therefore, the liquid fuel introduction passage 10 is
It is important to provide along the outer peripheral surface of the stack 6 along any one of the four surfaces excluding the upper and lower surfaces and in the direction (x direction in the drawing) orthogonal to the flow of the oxidant gas. . Further, in order to supply the liquid fuel in the liquid fuel introduction path 10 from the side surface of the stack 6 to the fuel electrode 2 by the capillary force, one of the four side surfaces of the stack, which is the end surface of the electromotive section 4, is formed. The liquid fuel introduction passage 10 is provided along at least one of the two side surfaces (for example, the side surface 4a). That is, the liquid fuel introduction passage 10 is a surface of the outer peripheral surface of the stack 6 that is formed by the end surface of the electromotive section 4, in other words, a surface that includes the end surface of the fuel electrode 2, and is parallel to the flow of the oxidant gas. Is provided along the at least one surface 4a arranged in the direction perpendicular to the flow of the oxidant gas. Further, in order to supply the liquid fuel to the fuel electrode 2 by the capillary force, the liquid fuel introduced into the liquid fuel introducing passage 10 is configured to come into direct contact with the electromotive portion end face 4a.

As a result, the entire surface of the end of the fuel electrode 2 can be brought into contact with the liquid fuel without obstructing the flow of the oxidant gas, and the liquid fuel in the liquid fuel introducing passage 10 can be smoothly moved by the capillary force. Can be supplied to the fuel electrode 2. In the fuel cell of this embodiment, the supply direction (z direction) of the oxidant gas and the introduction direction of the liquid fuel to the end surface of the stack 6 are basically orthogonal to each other, so that the structure is simplified. In addition to the above, there are few structural restrictions, and it is possible to reduce the size.

The fuel introducing passage constituting member 11 may be common to the fastening member of the stack 6 or may be separately provided, and the constitution and material thereof are not particularly limited. However, the fuel introduction path constituent member 1
The portion of the stack 1 that contacts the side surface of the stack 6 must be insulated in order to prevent a short circuit between the cells. This is done, for example, by constructing the fuel introducing passage constituting member 11 itself with an insulating material or by interposing an insulating material between the fuel introducing passage constituting member 11 and the stack 6.

The above-described shape of the liquid fuel introducing passage 10 is basically such that the liquid fuel is introduced from a fuel storage tank (not shown), and the introduced liquid fuel is supplied to the fuel electrode 2 by capillary force. If One of the methods for supplying the liquid fuel from the fuel storage tank to the liquid fuel introduction path 10
There is a method in which the liquid fuel in the fuel storage tank is naturally dropped and introduced into the liquid fuel introduction passage 10. This method can reliably introduce the liquid fuel into the liquid fuel introduction passage 10 except for the structural restriction that the fuel storage tank must be provided at a position higher than the upper surface of the stack 6. Another method is to draw the liquid fuel from the fuel storage tank by the capillary force of the liquid fuel introducing passage 10. According to this method, the fuel storage tank and the liquid fuel introduction path 10
It is not necessary to make the position of the connection point with the fuel inlet provided in the liquid fuel introduction path 10 higher than the upper surface of the stack 6. For example, when combined with the above-mentioned free fall method, the installation location of the fuel tank can be set freely. It has the advantage of being configurable.

In order to apply a capillary force to the liquid fuel introducing passage 10, although it depends on the type of liquid fuel and the material of the fuel introducing passage constituting member 11, a gap (indicated by t in the figure) of the liquid fuel introducing passage 10 is formed. It is preferably about 0.2 to 5 mm. If the gap t of the liquid fuel introduction passage 10 is less than 0.2 mm, the liquid fuel may be insufficiently supplied.
If it exceeds mm, there is a possibility that sufficient capillary force may not be obtained. Furthermore, when the operation of the battery is stopped for a long time, the liquid fuel in the liquid fuel introduction passage 10 is volatilized and wasted,
Considering the odor and the like caused by volatilization, it is advantageous that the volume of the liquid fuel introduction passage 10 is small. Further, in consideration of improving the capillary force, the clearance t of the liquid fuel introducing passage 10 is 3 mm.
The following is more preferable.

However, the liquid fuel introduced into the liquid fuel introducing passage 10 by the capillary force is continuously and smoothly applied by the capillary force to the fuel electrode 2
In order to supply the liquid to the fuel electrode 2, it is important to set the capillary force to the fuel electrode 2 to be larger than the capillary force of the liquid fuel introduction passage 10. Further, in order to improve the capillary force of the liquid fuel introduction passage 10, an insulating porous body or fiber may be arranged inside thereof. In this case, the clearance t of the liquid fuel introducing passage 10 may exceed 5 mm. The number of the liquid fuel introduction passages 10 is not limited to one along the side surface of the stack 6, and the liquid fuel introduction passages 10 may be formed on the other stack side surface.

Further, the fuel storage tank as described above is
It can be detachable from the battery body. As a result, by replacing the fuel storage tank, it becomes possible to continue the operation of the battery for a long time. In this case, in order to continue the operation of the device even when the battery is replaced, the fuel needs to remain in the battery when the fuel storage tank is disconnected. Such a fuel storage unit is provided in the liquid fuel introduction passage 10
And the supply portion to the fuel electrode 2 or the fuel electrode 2 itself,
Considering the replacement time of the fuel storage tank, it is desirable that the amount of remaining fuel be such that the device can operate for at least 1 minute or more. Further, the liquid fuel may be supplied from the fuel storage tank to the liquid fuel introducing passage 10 by the above-mentioned spontaneous fall or by pushing out the liquid fuel due to the internal pressure in the tank or the like. It is also possible to adopt a configuration in which the fuel is drawn out by the capillary force of 10. In this case, the outlet gap of the fuel storage tank is not restricted by the gap of the liquid fuel introduction passage 10 in the case of spontaneous fall or the internal pressure in the tank, but in the case of capillary force, the exit gap of the fuel storage tank is more than the gap of the liquid fuel introduction passage 10 It is desirable to increase the outlet clearance of the.

The liquid fuel introduced into the liquid fuel introducing passage 10 by the above-described method is supplied to the fuel electrode 2 by the capillary force. As the capillary force for drawing the liquid fuel to the fuel electrode 2 side, first, the capillary force of the porous body itself that becomes the fuel electrode 2 can be mentioned. When utilizing such a capillary force, the holes of the fuel electrode 2 which is a porous body are connected to form a so-called continuous hole, the diameter of the hole is controlled, and at least from the side surface of the fuel electrode 2 on the liquid fuel introducing passage 10 side. By forming the communication hole continuous to the other surface, the liquid fuel can be smoothly supplied by the capillary force even in the lateral direction. Further, when the cell area becomes large, not only the liquid fuel supply speed slows down, but also the cell reaction progresses intensively at the inlet side of the liquid fuel, so that the fuel supply amount decreases as the distance from the liquid fuel introduction passage 10 increases. May occur. In such a case, it is effective to provide the liquid fuel introduction passage 10 also on the other stack surface that satisfies the above-mentioned conditions.

The pore diameter and the like of the porous body which becomes the fuel electrode 2 may be any as long as the liquid fuel in the liquid fuel introduction passage 10 can be drawn in, and is not particularly limited, but the gap of the liquid fuel introduction passage 10 is not limited. In consideration of the above, it is preferable that the thickness is about 0.2 to 300 μm. Further, the volume of pores, which is an index of the continuity of pores in the porous body, is preferably about 35 to 80%. If the pore size is smaller than 0.2 μm,
It becomes difficult to manufacture the fuel electrode 2, and if it exceeds 300 μm, the capillary force decreases. Further, if the volume of the pores is less than 35%, the amount of continuous pores decreases and the number of closed pores increases, so that it is not possible to obtain sufficient capillary force. On the contrary, when the volume of the pores exceeds 80%, the amount of the continuous pores increases, but the strength becomes weak and the production becomes difficult. Practically, it is desirable that the pore diameter be in the range of 0.5 to 100 μm and the pore volume be in the range of 45 to 75%.

Further, in order to draw the liquid fuel into the fuel electrode 2 by the capillary force, side surfaces other than the side surface on the liquid fuel introduction path 10 side are arranged so that the air in the fuel electrode 2 is expelled by the drawn liquid fuel. It is preferable to open at least one of the above. However, it is preferable to close the side surfaces of the fuel electrode 2 other than the above-mentioned surfaces in order to suppress volatilization of the liquid fuel.

The capillary force for drawing the liquid fuel to the fuel electrode 2 side is not limited to the above-mentioned capillary force of the porous body itself which becomes the fuel electrode 2, and for example, as shown in FIG. The liquid fuel supply groove 12 is provided as a continuous groove in the horizontal direction (y direction in the drawing) on the surface in contact with the fuel electrode 2, and the capillary force of the liquid fuel supply groove 12 is used to move the liquid fuel to the fuel electrode 2 side. It can also be configured to retract. In this case, the liquid fuel introduction passage 10 is provided so that at least the open end of the liquid fuel supply groove 12 is in direct contact with the liquid fuel. It is also possible to use the capillary force of the liquid fuel supply groove 12 and the capillary force of the porous body itself which becomes the fuel electrode 2 in combination.

The shape of the liquid fuel supply groove 12 is not particularly limited as long as the capillary force can be exerted, but at least the capillary force of the groove 12 needs to be smaller than the capillary force of the fuel electrode 2. If the capillary force of the groove 12 is larger than that of the fuel electrode 2, the liquid fuel in the liquid fuel introducing passage 10 becomes
Although it is supplied into the liquid fuel supply groove 12, the fuel electrode 2
Can no longer be supplied to. Liquid fuel supply groove 12
Although the shape depends on the wettability between the constituent material of the channel / separator 5 and the liquid fuel, its width is 0.
It is preferably in the range of 2 to 10 mm.

When the width of the liquid fuel supply groove 12 exceeds 10 mm, the capillary force becomes small, and eventually the capillary force of the fuel electrode 2 becomes the main component, and it is meaningless to form the liquid fuel supply groove 12. On the contrary, if the width of the groove 12 is less than 0.2 mm, the capillary force is improved, but the supply of the liquid fuel does not catch up with the cell reaction, and it is difficult to cut the groove by the usual manufacturing method.
A special manufacturing method is required. The same applies to the depth of the groove,
The depth of the groove is preferably in the range of 0.1 to 2 mm. In particular, if the depth of the groove 12 is too deep, the thickness of the channel / separator 5 must be increased, and as a result, miniaturization is hindered. Furthermore, when a large amount of liquid fuel remains when the fuel supply is stopped and power generation is stopped, not only is it volatilized and wasted, but also odor may be emitted due to volatilization. The depth is more preferably 1 mm or less. The width of the groove is more preferably 5 mm or less, and more preferably 3 mm or less, in order to increase electrical contact in addition to the same reason.

Further, since the liquid fuel supply groove 12 draws the liquid fuel from the liquid fuel introduction passage 10 by its capillary force, as described above, the liquid fuel introduction groove 10 is drawn from the fuel storage tank to the liquid fuel introduction passage 10. When introducing the liquid fuel with, the capillary force of the liquid fuel supply groove 12 is set to be larger than the capillary force of the liquid fuel introduction passage 10. Such a difference in capillary force is basically determined by the cross-sectional areas of the liquid fuel introduction passage 10 and the liquid fuel supply groove 12, and the constituent material of the separator 5 and the material of the fuel introduction passage constituent member 11. Desirably, at least one of the width and the depth of the liquid fuel supply groove 12 is smaller than the gap t of the liquid fuel introduction passage 10. As described above, the shape of the liquid fuel supply groove 12 is set in consideration of the shapes of the porous body to be the fuel electrode 2 and the liquid fuel introduction passage 10. The shape of the liquid fuel supply groove 12 is the same as that of the oxidant gas supply groove 7.
The shape and the shape of the liquid fuel supply groove 7 should be taken into consideration. For example, the width and depth of the oxidant gas supply groove 7 are preferably set to be 1.1 to 20 times larger than that of the liquid fuel supply groove 12. More preferably, it is about 1.2 to 10 times.

The liquid fuel supply groove 12 does not necessarily have to be provided horizontally, but may be formed by inclining in the range of 45 to 90 degrees in the vertical direction (z direction). However, when the inclination becomes large, the liquid fuel supply groove 12
Since the formation region of is reduced and the effective fuel supply path is reduced accordingly, the inclination is preferably 30 degrees or less. In addition, the liquid fuel introduction path 10 is stacked in the stack 6
This is not the case when it is provided on both sides of.

As described above, the separator 5 also serving as the channel is used.
For example, by providing the liquid fuel supply groove 12 extending in the horizontal direction, the liquid fuel is supplied to the fuel electrode 2 from the entire end portion of the fuel electrode 2, and the fuel is simultaneously supplied in the lateral direction of the fuel electrode 2 through the groove 12. Since the liquid fuel can be supplied, the liquid fuel in the liquid fuel introducing passage 10 can be supplied to the fuel electrode 2 more smoothly. As a result, the battery reaction can be made to proceed uniformly over the entire surface of the electromotive section 4, and high efficiency can be achieved. In addition, in the above-described embodiment, the description has been given of the case where both the oxidant gas supply groove 7 and the liquid fuel supply groove 12 are formed in the channel / separator 5; May be installed. In such a case, it is possible to separate the liquid fuel and the oxidant gas by installing a gas-impermeable conductive plate between the channels or by closing a hole on the surface of at least one of the channels. . However, in order to reduce the number of parts and further reduce the size, it is preferable that the channels are also used.

Further, when the liquid fuel is drawn from the liquid fuel introducing passage 10 into the fuel electrode 2 by the capillary force, it is important to improve the capillary force. As described above, the capillary force increases as the gap between the capillary passages decreases and the wettability of the capillary passage with respect to the liquid fuel increases. From the viewpoint of increasing the wettability of the capillary passage to the liquid fuel, it is effective to improve the surface of the capillary portion that causes the capillary force, and it is particularly effective to provide an oxide film on the surface. That is, the liquid fuel supply groove 1 provided on the porous inner surface of the fuel electrode 2 or the channel / separator separator 5
By providing the oxide film on the inner surface of 2, the capillary force is significantly increased, and not only the speed of drawing the liquid fuel into the cell is increased, but also the reaching distance of the liquid fuel can be extended. This not only makes it possible to cope with a large area of the fuel cell, but also shortens the time required to start the cell. However, the oxide film is preferably formed so as not to reduce the porosity of the porous body. In particular, it is important not to block the inlet of the liquid fuel by forming an oxide film on the end surface of the fuel electrode 2 which is in contact with the liquid fuel introducing passage 10.

By the way, the fuel electrode 2 must conduct electrons generated as a result of the cell reaction. Therefore, the oxide film provided on the surface of the fuel electrode 2 should not interfere with the electron conduction. If the oxide film provided on the fuel electrode 2 is insulative, the oxide film is formed except for the surface of the fuel electrode 2 that is in contact with the separator 5 or the channel. Further, even when an oxide film is provided in the liquid fuel supply groove 12, the oxide film is formed only on the inner surface thereof.

Further, when the liquid fuel is introduced into the liquid fuel introducing passage 10 by the capillary force, it is effective to form an oxide film on the inner surface of the liquid fuel introducing passage 10.

As a method of forming such an oxide film,
Examples include a method of raising the temperature in an oxidizing atmosphere or a steam atmosphere to oxidize the surface of the metal, a method of treating with a chemical such as an alkali, and the like. The oxide film can be removed by a mechanical method such as polishing or cutting.

In each of the above-mentioned embodiments, the fuel cell having the stack 6 in which the electromotive portions 4 are laminated via the separator / channel separator 5 has been described. is not. For example, as shown in FIG.
It is also possible to form a stack 13 by directly laminating a plurality of electromotive portions 4 sandwiched between the fuel electrode 2 and the oxidant electrode 3. At this time, the oxidant gas supply groove 7 is formed as a continuous groove in the direction perpendicular to the surface of the fuel electrode 2 which is in contact with the oxidant electrode 3, as shown in FIG. 4, or as shown in FIG. The oxidizer electrode 3 is formed in a direction perpendicular to the surface in contact with the fuel electrode 2.
Further, as shown in FIG. 6, an oxidant gas supply groove 7 may be provided on the surface of the oxidant electrode 3 that contacts the electrolyte plate 1. Furthermore, the oxidant gas supply groove 7 may not be in contact with the electrolyte plate 1 or the fuel electrode 2. In this way, the fuel electrode 2 and the oxidant electrode 3
By directly forming the oxidant gas supply groove 7 in the above, the oxidant gas can be smoothly flowed. The other configurations, that is, the liquid fuel introduction passage 10 and the like are similar to those of the fuel cell of the above-described embodiment. Further, with the above configuration, the number of parts can be further reduced, so that further downsizing can be achieved.

When the fuel electrode 2 and the oxidant electrode 3 are in direct contact with each other as described above, the fuel electrode 2
Therefore, it is necessary to prevent the liquid fuel from being drawn into the oxidizer electrode 3. This is because if the liquid fuel is drawn into the oxidant electrode 3, it becomes difficult for the oxidant gas to flow, which hinders the cell reaction. As a method for preventing the inflow of the liquid fuel into the oxidant electrode 3 described above, basically, the pore diameter of the porous body which becomes the oxidant electrode 3 is controlled to a size such that the liquid fuel is not drawn in by the capillary phenomenon. do it. However, depending on the equipment to be applied, there are cases where the above-mentioned pore size must be sized so as to draw the liquid fuel by the capillary phenomenon. In such a case, regardless of whether the oxidant gas supply groove 7 is formed in the fuel electrode 2 or the oxidant electrode 3, the surface of the porous body that becomes the fuel electrode 2 on the oxidant electrode 3 side is All you have to do is close the hole. However, when the oxidant electrode 3 is provided with the oxidant gas supply groove 7, the holes on the surface of the oxidant electrode 3 on the side of the fuel electrode 2 other than the groove 7 may be closed. There is a possibility that it may enter the oxidant electrode 3 through the side surface. In this case, it is preferable to close the contact surface of the oxidant electrode 3 with the fuel electrode 2 and the hole on the side surface of the oxidant gas supply groove 7.

As a method of closing the holes, a material that does not hinder the conduction between the fuel electrode 2 and the oxidizer electrode 3 is applied in the form of slurry, or the surface is subjected to polishing, grinding, or the like. Examples thereof include a method of closing the holes by plastic deformation generated in the porous body, and a method of melting and solidifying the surface with an electron beam or a laser. When the oxidant gas supply groove 7 is formed in the oxidant electrode 3, a conductive material such as a metal plate that does not allow liquid fuel to pass through is sandwiched at the interface between the fuel electrode 2 and the oxidant electrode 3. Also, it is possible to prevent the liquid fuel from entering the oxidant electrode 3.

In each of the fuel cells of the above-described embodiments, the liquid fuel in the liquid fuel introduction passage 10 is in direct contact with the end of the oxidizer electrode 3 or the end of the electrolyte plate 1 which is a porous body. Has become. In particular, since the oxidizer electrode 3 cannot supply gas to the electrolyte plate 1 unless it is a porous body, the liquid fuel is drawn into the oxidizer electrode 3 by capillary force when it comes into contact with the liquid fuel at its end. The drawn liquid fuel blocks the passage of the oxidant gas. Therefore, it is necessary to prevent the liquid fuel from entering from the end of the oxidizer electrode 3.

To prevent the liquid fuel from entering the oxidizer electrode 3,
Basically, the pore size of the porous body that becomes the oxidizer electrode 3 may be controlled to a size that does not draw the liquid fuel by the capillary force. However, depending on the equipment to be applied, there are cases where the hole diameter must be set to a size that allows the liquid fuel to be drawn in by a capillary force. In such a case, the liquid fuel can be prevented from entering by, for example, closing a hole in the surface of the oxidizer electrode 3 on the liquid fuel introduction passage 10 side, or by injecting the liquid fuel introduction passage 10 of the oxidizer electrode 3.
The surface contacting with is covered with a seal member or the like. Specific examples of these methods include a method of coating the side surface with a plate, foil, film or the like of metal, inorganic material, ceramics, organic material, etc., or a method of applying these single or composite powders in a slurry form. To be done. Further, it is also possible to apply the above-mentioned method utilizing plastic deformation or the method of melting and solidifying.

As the latter method of covering the side surface of the oxidizer electrode 3 with a seal member, when the separator 5 or the channel is used, for example, as shown in FIG.
Another method is to sandwich the seal member 14 between the fuel electrode 2 and the separator 5 serving also as a channel so as to be located on the side surface of the electrolyte plate 1. In this case, if the seal member 14 has electronic conductivity, a short circuit occurs between the fuel electrodes 2 and an output cannot be obtained. Therefore, the seal member 14 is made of an insulating material. Note that the seal member 14 does not necessarily have to be sandwiched between the fuel electrode 2 and the channel / cumulative separator 5, but may be sandwiched between the fuel electrode 2 or only the side surface of the oxidizer electrode 3. You can also

When a separator or a channel is not used, the side surface of the oxidizer electrode 3 is sealed by sandwiching a similar seal member 14 between the fuel electrodes 2 as shown in FIG. Can be covered with. At this time, the seal member 14 may be sandwiched only on the side surface of the oxidizer electrode 3.

By the way, a stack 6 in which the electromotive sections 4 are laminated
In (13), the stack 6 (13) must be tightened in order to secure electrical contact between the electromotive sections 4.
In this case, the sealing member 14 is made of a material having rubber elasticity, in other words, when the electromotive section 4 is tightened, the parts of the electromotive section 4 and the channel-cum-separator 5 are used.
By elastically deforming the seal member 14 sandwiched between (hereinafter, referred to as stack constituent parts) rubber, it is possible to surely obtain the above electrical contact and obtain a liquid fuel sealing effect. it can.

That is, in the case where the material sandwiched between the stack constituent parts is a rigid material which does not deform, if the thickness of this rigid material is smaller than the thickness of the stack constituent part covered by it, the space between the stack constituent parts and the rigid material is reduced. Liquid fuel cannot be sealed because there is a gap. On the contrary, if the thickness of the rigid material is thicker than the thickness of the stack component covered by it, even if the stack 6 (13) is tightened, a gap is created between the oxidizer electrode 3 and the electrolyte plate 1, etc. The electrical contact cannot be secured. In principle, if the above-mentioned thickness is the same, it is possible to achieve both electrical contact and liquid fuel sealing, but in practice, the thickness of the electromotive section 4 components should be kept strictly constant. It is difficult.

On the other hand, by providing the seal member 14 sandwiched between the stack constituent parts with rubber elasticity, the seal member 14 is deformed when the stack 6 (13) is tightened, and the thickness and the seal of the stack constituent parts are reduced. The difference in thickness of the member 14 can be absorbed. This makes it possible to ensure electrical contact and liquid fuel sealing performance. As the rubber elastic material, various materials can be used as long as they exhibit rubber elasticity, such as raw rubber and Teflon rubber.

Further, when the seal member 14 is sandwiched between the stack components as described above, in order to prevent the liquid fuel from entering the oxidizer electrode 3 more reliably, as shown in FIG. It is effective to form a gap 15 between the electrode 3 and the seal member 14 so that the seal member 14 and the oxidant electrode 3 do not come into direct contact with each other. As a result, even if the liquid fuel leaks from the defective portion of the seal, it is possible to prevent the liquid fuel from being directly drawn into the oxidant electrode 3. Further, in order to ensure that the liquid fuel is prevented from entering the oxidant electrode 3, it is necessary to close the hole on the side surface of the oxidant electrode 3.

It is not always necessary to provide a seal member having rubber elasticity on the side surface of the oxidizer electrode 3 opposite to the liquid fuel introduction passage 10, and a part of the insulative battery accommodating member also serves as a seal member. May be. In this case, from the viewpoint of preventing the liquid fuel from entering the oxidant electrode 3, it is preferable to provide a gap at least between the end of the oxidant electrode 3 and the battery housing member.

1 to 9, the case where the fuel electrode 2, the electrolyte plate 1 and the oxidizer electrode 3 are in contact with each other on a plane is shown. However, in order to increase the cell area, the respective contact surfaces are It may be curved. FIG. 10 shows a case where the contact surface between the fuel electrode 2 and the electrolyte plate 1 is wavy.
The corrugated surface may be formed on at least one of the contact surface between the fuel electrode 2 and the electrolyte plate 1 or the contact surface between the oxidizer electrode 3 and the electrolyte plate 1, but from the viewpoint of cell reaction, the fuel electrode 2 It is more preferable that the contact surface between the electrolyte plate 1 and the electrolyte plate 1 is corrugated.

Further, in the fuel cell of the present invention, by further providing a groove in the vertical direction on the surface of the fuel electrode in contact with the electrolyte plate, carbon dioxide generated by the decomposition reaction of the liquid fuel at the fuel electrode can be efficiently produced. Can be discharged.

In the fuel cell of the present invention, as described above, the stack 6 (13) must be clamped to secure the electrical contact between the electromotive sections 4. A method similar to that of a conventional fuel cell can be applied to this tightening, but as shown in FIG.
It is also possible to adopt a structure in which the battery is tightened by the battery tightening member 17 which is made of a material having insulating properties and rubber elasticity. By using such a battery tightening member 17, it becomes possible to tighten the stack 16 easily and reliably.

When the battery tightening member 17 is used as described above, the inner size thereof is smaller than the outer size of the stack 16 in order to tighten the stack 16. Then, after expanding the battery tightening member 17 and inserting the stack 16 therein, the force for expanding the battery tightening member 17 is released, and the stack 16 is tightened by the restoring force of the rubber elastic material. In this case, the liquid fuel introduction passage 10 may be provided in the battery tightening member 17 as shown in FIG. 11, or may be formed as a separate component from the battery tightening member 17.

By the way, the cell fastening member 17 formed of the above-mentioned material exhibiting rubber elasticity can be used not only for the methanol fuel cell shown in each of the above-mentioned embodiments but also for various fuel cells. However, the applicable condition is that the heat resistant temperature of the rubber elastic material is equal to or higher than the operating temperature of the fuel cell. For this reason, when using a general heat resistant rubber material, for example, the above-mentioned methanol fuel cell, for example, a phosphoric acid fuel cell, a solid polymer electrolyte fuel cell, an alkaline electrolyte fuel cell It can be applied to hydrazine fuel cells and the like. Further, the material exhibiting rubber elasticity is not limited to various kinds of rubber, and a metal spring or the like can be used. In such a case, it can be applied to a molten carbonate fuel cell, a solid oxide fuel cell, and the like.

When the cell tightening member formed of the above-mentioned material exhibiting rubber elasticity is applied to a general fuel cell, for example, as shown in FIG. 12, it is sandwiched between the fuel electrode, the oxidizer electrode and both of these electrodes. In the same manner as in the above-described embodiment, the periphery of the stack 18 in which a plurality of electrolyzed plates and, if necessary, electromotive parts (cells) having gas channels are laminated with a separator interposed between them is provided with rubber elasticity. Tighten with the battery tightening component 19 formed of the material shown.

FIG. 12 shows an example in which the battery tightening parts 19 are uniformly tightened from the four periphery of the stack 18,
It is sufficient that the tightening force is applied at least in the stacking direction of the stack 18. That is, since the original purpose of tightening the stack 18 is to improve the contact between the battery components and to minimize the electric resistance caused by the contact resistance between the components, the tightening force is at least the stacking direction of the stack 18. You just have to join. Therefore, as shown in FIG. 13, it is also possible to use a battery fastening component 20 or the like in which a rubber elastic component 20a is provided in the stacking direction of the stack 18.

As shown in FIG. 12, when the entire outer peripheral surface of the stack 18 is covered with a rubber elastic material, the battery fastening component 19 also functions as a heat insulating material. Further, as shown in FIG. 13, in the case of the battery fastening component 20 in which a part of the side surface of the stack 18 is opened, the open portion 20b thereof is provided.
The heat generated by the battery reaction can be released to the outside.
These can be selected according to the usage pattern of the fuel cell. For example, when improving the initial operability or when the heat radiation from the fuel cell adversely affects the surrounding parts and the like. A battery fastening component 19 as shown in FIG. 12 is suitable. Further, when excessive heat storage adversely affects the fuel cell, the cell fastening component 20 as shown in FIG. 13 is suitable. When using the battery tightening component 19 as shown in FIG. 12, a cooling mechanism for the fuel cell may be separately provided and used.

When the battery tightening components 19 and 20 shown in FIGS. 12 and 13 are used and the tightening force in the plane direction of the stack 18 is too large, excessive force is applied to the corners of the stack 18 and The parts may be damaged.
Therefore, basically, the force in the plane direction of the stack 18
Although it is necessary to adjust the tightening force within a range where the corners are not damaged, it is preferable to cover the corners of the stack 18 with a rigid material and then tighten the battery tightening parts 19 and 20.
In particular, as shown in FIG. 14, a rigid member 21 having a larger area than the stack 18 is installed on both end faces of the stack 18 in the stacking direction, and is tightened with a battery tightening component 19 (20) made of a rubber elastic material. By Sutaku 1
It is possible to reduce the force applied to each corner portion 18a of No. 8 to the extent that it can be almost ignored. If the rigid material has a structure that short-circuits the cells, for example, if the rigid material is folded so as to surround the corners of the stack 18, it is necessary to insulate the stack 18 from the cells. However, when the rigid material is also used as the electrical take-out plate,
It is preferably a single conductive plate.

FIG. 12 shows the structure of the battery tightening component.
13 and not limited to that shown in FIG. 13 as long as it has a structure in which at least the stacking direction of the stack can be tightened by rubber elasticity as described above. For example, as shown in FIG. 15 and FIG. It is also possible to form a battery tightening component by combining and.

In FIG. 15, the rigid members 22 are arranged on both end faces of the stack 18 in the stacking direction.
A structure is shown in which the two are connected by a rubber elastic component 23 that covers the side surface of the stack 18 and the stack 18 is tightened in the stacking direction. 16 shows the stack 1
8 shows a structure in which rigid members 22 are arranged on both end faces in the stacking direction of 8, and the periphery including these rigid members 22 is fastened with a rubber elastic member 24 in a band shape. in this way,
As for the combination of the rubber elastic material and the rigid material, it is sufficient that at least the stacking direction of the stack is clamped by the rubber elasticity, and various combinations can be used.

The various battery tightening components described above may be tightened from above the manifold if the stack 18 is an external manifold type. In this case, FIG.
As shown in, a part of the battery fastening component can also be used as the manifold.

In order to tighten the stack, the various battery tightening components described above require at least the inner dimension corresponding to the stacking direction of the stack to be smaller than the outer dimension of the stack in the stacking direction. In some cases, the battery fastening components must be unrolled once, the stack inserted therein and then the force unfolding the battery fastening components must be released. At this time, as shown in FIG. 17, the battery tightening parts 2 are provided to facilitate the spreading of the battery tightening parts and the release of the force after the stack is inserted.
It is preferable to provide notches 25a for widening at the inner four corners of No. 5. The stack can be easily tightened by inserting a rod for expanding the battery tightening component 25 into the notches 25a at the four corners described above, releasing the force, and then pulling out the rod. In addition, as shown in FIG. 14, the rigid members 21 having a larger area than the stack 18 are installed on both end surfaces, and the space formed between the battery fastening component 19 and the stack 18 is utilized to make the battery fastening component 1
9 can be widened and the release of force can be facilitated.

Various rubber materials can be used as the rubber elastic material used for the above-mentioned battery tightening component as long as it has insulation properties and can obtain a necessary tightening force in the stacking direction of the stack. Examples include raw rubber and Teflon rubber. A rubber material having heat resistance, acid resistance, and alkali resistance is used depending on the type of fuel cell.

By using the battery tightening component that tightens at least the stacking direction of the stack with the rubber elasticity as described above, the tightening work becomes easier than the conventional bolt tightening method, and the tightening component itself has a small size.
Since the weight can be reduced, it greatly contributes to downsizing of the fuel cell. Further, since the tightening force can be easily adjusted, it is easy to deal with various fuel cells.

Further, the fuel cell of the present invention is not limited to the presence or absence of the catalyst layer in the fuel electrode 2 and the oxidizer electrode 3 as described above, but the liquid fuel is supplied to the fuel electrode 2 by the capillary force. Therefore, it is preferable to increase the efficiency of the oxidation reaction on the side of the fuel electrode 2 and increase the mobility of the generated protons. As a method of satisfying such a requirement, for example, the fuel electrode 2 is made to exist on a heat- and acid-resistant carrier in the form of island-shaped fuel oxidation catalysts that do not substantially overlap with each other, and at least the surface of the fuel oxidation catalyst is heat- and acid-resistant There is a method of forming the fuel oxidation catalyst particles in the presence of a proton conductive substance.

Specific examples of the fuel oxidation catalyst particles as described above include: (a) The fuel oxidation catalyst is present on the heat-resistant and acid-resistant carrier in an island shape without substantially overlapping each other. Fuel oxidation catalyst particles whose surface is covered with a heat-resistant and acid-resistant proton conductive thin film.

(B) A fuel oxidation catalyst is present in an island shape on a heat- and acid-resistant support substantially not overlapping with each other, and at least the surface of the fuel oxidation catalyst is proton-conductive with a polymer network having heat and acid resistance. Examples include fuel oxidation catalyst particles covered with a thin film holding a substance.

In each of the above (a) and (b),
The fuel electrode 2 is basically composed of a porous body of a carrier made of carbon particles carrying a fuel oxidation catalyst, Ti carbide, or the like. Specifically, the fuel oxidation catalyst particles composed of a carrier carrying the above fuel oxidation catalyst are constituted by a porous body held by a hydrophobic resin binder such as polytetrafluoroethylene. The fuel oxidation catalyst particles are covered with the thin film of any one of (a) and (b). The fuel oxidation catalyst may be a Pt-R together with a precious metal catalyst, for example, a platinum group metal such as Pt or Pd.
u alloy, Pt-Au alloy, Pt-Sn alloy, Pt-Re
Alloys, Pt-Mo alloys, Pt-Ti alloys and the like can be used.

As shown in FIG. 18, the fuel oxidation catalyst particles of the above (a) are formed on the surface of the carrier particles 26 made of conductive particles having heat and acid resistance such as carbon particles and Ti carbide as described above. The fuel oxidation catalyst 27 is present in an island shape, and the surfaces of the fuel oxidation catalyst 27 and the carrier particles 26 are covered with a heat conductive and acid resistant proton conductive thin film 28. If the proton conductive thin film 28 covers at least the surface of the fuel oxidation catalyst 27, the effect can be obtained.
As shown in FIG. 8, by covering the entire surface of the carrier particles 26 with the proton conductive thin film 28, it is possible to prevent the carrier particles 26 from being corroded, and it is possible to extend the life. Become.

The above-mentioned proton conductive thin film 28 may be an organic material or an inorganic material as long as it is a heat and acid resistant material.
Among them, an ion exchange resin having an organic fluorine-containing polymer as a skeleton, for example, a perfluorocarbon sulfonic acid resin is preferable. The thickness of the proton conductive thin film 28 is preferably 1 μm or less. If the film thickness is too large, the reaction may be adversely affected. As a method for covering the surface of the fuel oxidation catalyst with a proton conductive thin film, a method of dissolving the ion exchange resin as described above and coating the same is common and simple. Above all, thickness 1
An electrolytic coating method using a solutionized ion exchange resin is excellent as a method for forming an extremely thin and uniform thin film having a thickness of μm or less.

Further, as shown in FIG. 19, the fuel oxidation catalyst particles of (b) above are the same as those of (a) above, but the fuel oxidation catalyst 27 and the carrier particles are present on the surface of the carrier particles 26 in the form of islands. The surface of the particle 26 is covered with a thin film 31 in which a proton conductive material 30 is held in a polymer network 29 having heat and acid resistance.

As the polymer network 29 described above, various polymer materials can be used as long as they have heat and acid resistance and are excellent in the binding force with the carrier and the fuel oxidation catalyst. Considering the binding force with the carrier and the fuel oxidation catalyst, polyaniline, polypyrrole, polyphenylene sulfide, etc. obtained by electrolytic polymerization are particularly preferable.
As the proton conductive substance 30 held in the polymer network 29, various materials can be used as long as they are heat and acid resistant materials, and for example, a monomer or polymer having proton conductivity is used. Examples of the proton conductive monomer include trifluoromethanesulfonic acid, derivatives of fluorinated sulfonic acid such as tetrafluoroethanedisulfonic acid, (HO) ₂ OP (CF ₂ ) PO (OH) ₂ and (HO) ₂
Fluorinated diphosphoric acid derivatives such as OP (CF ₂ ) ₂ PO (OH) ₂ ,
(CF ₃ SO ₂ CH ₂ SO ₂ CF ₂ CF ₂ ) ₂ , CF ₃ SO ₂ NHSO ₂ C ₄ F
Derivatives of fluorinated sulfonyl acids such as ₉ are exemplified. In addition, examples of the proton conductive polymer having similar properties include ion exchange resins having an organic fluorine-containing polymer as a skeleton, such as perfluorocarbon sulfonic acid resin. Practically, Nafion 117 (trade name, manufactured by DuPont), DOW membrane (trade name, manufactured by Dow Chemical Co., Ltd.) and the like are used as a solution, and polymer molecules contained therein are retained in a polymer network for use.

As a method of forming the thin film 31 in which the proton conductive material 30 is held by the polymer network 29, it is preferable to use electrolytic polymerization as described above. For example, with a support carrying a fuel oxidation catalyst, a porous electrode substrate is prepared, which is used as one electrode of electrolytic polymerization, and placed in an electrolytic bath containing a polymer network material and a proton conductive substance, Electrolytic polymerization is carried out by energizing the electrode and the counter electrode. As a result, a polymer network is formed while incorporating the proton conductive substance therein, and such substance is incorporated into the electrode substrate.
By such electrolytic polymerization, the surface of the fuel oxidation catalyst on the support is covered with a thin film that holds the proton conductive material in the polymer network. At this time, electrolytic polymerization is preferably carried out by applying a pulsed electric current. This allows
It is possible to efficiently incorporate a polymer network that holds a proton conductive substance into the micrometer-order micropores of the electrode substrate. The proton conductive substance may be added to the electrolyte of the fuel cell in advance and incorporated into the polymer network during the cell reaction. Also,
The film thickness can be controlled by the amount of electricity flowing, and it is preferable that the film thickness is approximately the same as that of the proton conductive thin film 28 in (a) above. In the fuel cell using the fuel electrode as described above, as shown in FIG.
As shown in 0, the heat and acid resistant proton conductive thin film 28 covering the surface of the fuel oxidation catalyst 27 in the fuel electrode and the thin film 31 in which the proton conductive substance is held in the polymer network having heat and acid resistant are Since it functions as a transfer passage for protons (H ⁺ ) generated by the oxidation reaction of liquid fuel,
The liquid fuel drawn into the fuel electrode by the capillary phenomenon can be reacted with high efficiency, and the performance of the fuel electrode can be improved. Furthermore, the thin films 28 and 3 having proton conductivity.
The presence of protons in 1 allows the fuel to be, for example, a methanol + water system. Therefore, it is not necessary to consider the acid resistance of the fuel cell constituent material, which contributes to cost reduction. Also, the life characteristics of the constituent materials are improved. Further, the thin films 28 and 31 having further proton conductivity are
In the case of a water-containing membrane represented by Nafion 117, even if a fuel (for example, methanol + water or dilute sulfuric acid) is supplied as a gas, the water-absorbing ability of the membrane can exert the fuel oxidation catalytic ability.

Next, specific examples of the simplified and miniaturized fuel cell, which is the first object of the present invention, and the evaluation results thereof will be described.

Example 1 A liquid fuel cell having the structure shown in FIG. 1 was produced in the following manner. First, 60 mm x with an average pore size of 20 μm
A porous body of 50 mm was used as the fuel electrode 2, and a porous body of the same shape having an average pore diameter of 30 μm was used as the oxidizer electrode 3, and the electrolyte plate 1 was sandwiched between them. These were laminated so that the number of laminated layers would be 10 with the oxidant gas supply groove 7 having a depth of 0.7 mm and a width of 10 mm and being made of a metal plate serving also as a channel 5 to form a stack 6. .
The holes on the surface of the oxidizer electrode 3 which contact the liquid fuel introduction passage 10 were polished and closed with abrasive paper. In addition, the liquid fuel introduction path 1
The shape of 0 had a gap of 1 mm.

When a liquid mixture of methanol and dilute sulfuric acid was introduced as a liquid fuel into the liquid fuel cell thus obtained, the liquid fuel was supplied to the entire surface of the fuel electrode 2, and the air also smoothly flowed, which was excellent. The battery reaction was able to proceed.

Further, when an oxide film was provided on the inner surface of the porous body to be the fuel electrode 2, and a fuel cell was similarly prepared,
The liquid fuel could be supplied more smoothly, and the cell reaction could proceed more favorably.

The following tests were conducted in order to measure the improvement in the capillary force due to the formation of the oxide film. Two copper plates with an oxide film formed on the surface were made into a simulated fuel introduction path so that the gap between both plates was 1 mm, and this was immersed in methanol, and compared with the case of a copper plate without an oxide film. . as a result,
In the copper plate having the oxide film, the rising height of methanol was about 5 times that of the copper plate having no oxide film. Also,
When the time required for methanol to rise to the same distance was measured, the copper plate having an oxide film was about 1/8 of the copper plate having no oxide film. Next, after forming an oxide film on the inner surface of the nickel porous body having an average pore diameter of 20 μm, the oxide film on the surfaces other than the side surfaces is removed by polishing, and this is immersed in methanol to raise the height of methanol. Was measured until the methanol rose to a height of 10 mm. As a result, in the Ni porous body having an oxide film, the rising height is about 3 times and the time is about 1 time as compared with the Ni porous body having no oxide film.
It was / 5. From the above test results, it can be seen that formation of an oxide film is effective for improving the capillary force.

Further, in the above liquid fuel cell, as shown in FIG.
As shown in FIG. 11, a Teflon rubber seal member 14 having a thickness of 5 mm is arranged between the fuel electrodes 2, and the stack 6 (16) is tightened by a rubber battery tightening member 17 as shown in FIG. A fuel cell was produced.
When liquid fuel was also supplied to this liquid fuel cell, the liquid fuel did not enter the oxidizer electrode 3, and the effect of the seal member 14 could be confirmed. Further, there is no looseness between the stack components, and the battery tightening member 1
The usefulness of 7 was confirmed.

Example 2 In the above Example 1, the separator 5 also serving as the channel was used.
A similar liquid fuel cell (fuel cell shown in FIG. 3) was prepared except that a liquid fuel supply groove 12 having a depth of 0.5 mm and a width of 0.5 mm was provided on the surface of the fuel electrode side. When liquid fuel was similarly introduced into this liquid fuel cell, the liquid fuel was smoothly supplied to the entire surface of the fuel electrode 2 and the cell reaction could proceed well.

Example 3 A liquid fuel cell having the structure shown in FIG. 4 was produced in the following manner. First, 60 mm x with an average pore size of 20 μm
An oxidant gas supply groove 7 having a depth of 0.7 mm and a width of 10 mm was formed in a porous body of 50 mm, and the hole on the groove forming surface was polished with abrasive paper to close it to form a fuel electrode 2. The average pore size is 3
The pores on one side of the porous body having the same shape of 0 μm were polished with abrasive paper to close the pores, thereby forming an oxidizer electrode 3. The electrolyte plate 1 was sandwiched between these and laminated so that the number of laminated layers would be 10 to form a stack 13. The shape of the liquid fuel introduction passage 10 was set to a gap of 1.5 mm.

When a liquid mixture of methanol and dilute sulfuric acid was introduced as a liquid fuel into the liquid fuel cell thus obtained, the liquid fuel was supplied to the entire surface of the fuel electrode 2 and the air also smoothly flowed. The battery reaction was able to proceed.

When the effect of the oxide film and the effect of the seal member 14 were confirmed in the same manner as in Example 1, good results were obtained as in Example 1. Further, when the same liquid fuel cell (fuel cell shown in FIG. 5) was produced by forming the oxidant gas supply groove 7 in the oxidant electrode 3, the same result was obtained.

Next, specific examples of the fuel oxidation catalyst in the present invention and the evaluation results thereof will be described.

Example 4 As a raw material for a fuel oxidation catalyst, a heat-treated conductive carbon black Vulcan XC- having a specific surface area of 100 m ² / g was used.
72R (trade name, manufactured by Cabot) with 20% by weight of platinum catalyst
The supported one was prepared. On the surface of this fuel oxidation catalyst raw material, Nafion 117 (trade name, manufactured by DuPont), which is one of the perfluorocarbon sulfonic acid resins, was dissolved into a Nafion solution (Nafion 117 was dissolved in a mixed solvent of lower alcohol and water). A diluted Nafion solution (concentration: about 0.01% by weight) obtained by dialysis of a substance (concentration: about 5% by weight) was used to form a proton conductive thin film having a thickness of about 1 μm (hereinafter referred to as a modification catalyst). Call).

The above modified catalyst was ultrasonically dispersed in a polytetrafluoroethylene aqueous suspension TFE-30 (trade name, manufactured by DuPont). Next, aluminum trichloride was added to this mixed suspension to coagulate and precipitate cotton-like lumps. A cotton-like mixed mass containing this modified catalyst (70% on a dry weight basis) and polytetrafluoroethylene,
It was carried on carbon paper, pressed and dried, and baked in nitrogen at 300 ° C. for 20 minutes to obtain an electrode. The obtained electrode was adjusted to contain 1.5 mg of platinum per unit area (1 cm ² ) of the electrode.

Using the fuel electrode thus obtained, and
The fuel electrode half-cell characteristics were measured at 60 ° C. using an aqueous solution prepared by adding 1 mol methanol to mol sulfuric acid as a liquid fuel.
As a result, the limiting current density of the fuel electrode was 100 mA / cm ² ,
It was confirmed that the polarization characteristics were excellent and the performance was high.

Comparative Example 1 A fuel electrode was obtained in the same manner as in Example 4 except that the same raw material for the fuel oxidation catalyst as in Example 4 was not covered with the proton conductive membrane. When the half cell characteristics of the obtained fuel electrode were measured in the same manner as in Example 4, the limiting current density of the fuel electrode was 60 mA / cm ² .

Example 5 The same fuel oxidation catalyst as in Example 4 was prepared, and this fuel oxidation catalyst raw material was used as a polytetrafluoroethylene aqueous suspension TF.
It was dispersed in E-30 (trade name, manufactured by DuPont) by ultrasonic waves. Next, aluminum trichloride was added to this mixed suspension to coagulate and precipitate cotton-like lumps. A cotton-like mixed mass containing this catalyst raw material (70% on a dry weight basis) and polytetrafluoroethylene was supported on carbon paper, dried after pressing, and baked in nitrogen at 300 ° C. for 20 minutes to prepare an electrode substrate. And

Next, using the above electrode substrate, electrolytic polymerization was carried out according to the following procedure to form a thin film having a proton conductive monomer held in the polymer network on the surface of the catalyst. Polyaniline was used as the polymer network, and trifluoromethanesulfonic acid was used as the proton conductive monomer. First, the counter electrode and the electrode substrate were placed as working electrodes in an electrolytic cell containing an electrolytic polymerization solution containing a mixed solution of aniline 1 mol / 1 and trifluoromethanesulfonic acid 2 mol / 1.
While maintaining the temperature of the electrolytic polymerization solution at 0 ° C., a constant current of 2 mA / cm ² was applied for 5 minutes, and then a constant current of 20 mA / cm ² was applied for 10 minutes to carry out electrolytic polymerization. In this way
A thin film, in which trifluoromethanesulfonic acid was retained in the polyaniline network, was formed on the surface of the catalyst to obtain an electrode for fuel electrode.

Example 6 An electrode substrate prepared in the same manner as in Example 5 was used, and a thin film in which a proton conductive polymer was retained in the polymer network in place of the proton conductive monomer of Example 5 was used. It was formed on the surface of the catalyst by the same electrolytic polymerization as in No. 5. Polyaniline was used as the polymer network, and Nafion 117 (trade name, manufactured by DuPont) was used as the proton conductive polymer. The electrolytic polymerization conditions were the same except that Nafion 117 was used instead of trifluoromethanesulfonic acid. In this way, Nafion 117 in the polyaniline network
Was formed on the surface of the catalyst to obtain a fuel electrode.

The fuel electrode half-cell characteristics of the electrodes of Examples 5 and 6 obtained above were measured in the same manner as in Example 4. As a result, the limiting current density of the fuel electrode of Example 5 was 102 mA / cm ² , and the limiting current density of the fuel electrode of Example 6 was 95 mA / cm ² , both showing excellent polarization characteristics and high performance. Was confirmed.

Example 7 Using the electrode substrate produced in the same manner as in Example 5, electrolytic polymerization was carried out according to the procedure shown below. The polymer network and the proton conductive monomer were made of the same material as in Example 5. First, the counter electrode and the above electrode substrate were placed as working electrodes in an electrolytic cell containing an electrolytic polymerization solution containing a mixture of aniline 1 mol / 1 and borofluoric acid 2 mol / l, and the same as in Example 5. Electropolymerization was performed under the conditions.
In this way, a polyaniline network film was formed on the surface of the catalyst.

Using the fuel electrode thus obtained, and
The fuel electrode half-cell characteristics were measured at 60 ° C. with a liquid fuel containing 1 vol% of trifluoromethanesulfonic acid added to an aqueous solution of 1 mol methanol added to mol sulfuric acid.

Example 8 An electrode prepared in the same manner as in Example 7 was used, and 1
6% of Nafion 117 was added to an aqueous solution of 1 mol methanol added to mol sulfuric acid as a liquid fuel.
The fuel cell half-cell characteristics were measured at 0 ° C.

The limiting current densities of Examples 7 and 8 were 98 mA / cm ² and 93 mA / cm ² , respectively, and it was confirmed that they had excellent polarization characteristics and high performance.

Example 9 Using the electrode substrate prepared in the same manner as in Example 5, electrolytic polymerization was carried out according to the procedure described below while applying a rectangular pulse current, which was slightly different from that in Example 5. A thin film containing a proton conductive monomer
Formed on the surface of the catalyst. Polyaniline was used as the polymer network, and trifluoromethanesulfonic acid was used as the proton conductive monomer. First, the counter electrode and the electrode substrate were placed as working electrodes in an electrolytic cell containing an electrolytic polymerization solution containing a mixed solution of aniline 1 mol / 1 and trifluoromethanesulfonic acid 2 mol / 1. While maintaining the temperature of the electropolymerization liquid at 0 ° C., pulse electropolymerization was performed using a rectangular pulse current with an electricity amount of 5 m coulomb / cm ² . The condition at this time is that the current density is 5
mA / cm ² , pulse on time 5 msec, pulse off time 20 msec (duty cycle: 0.2). In this way, a thin film holding trifluoromethanesulfonic acid in the polyaniline network is formed on the surface of the catalyst,
An electrode for fuel electrode was obtained.

Example 10 An electrode substrate prepared in the same manner as in Example 9 was used, and a thin film in which a proton conductive polymer was retained in place of the proton conductive monomer of Example 9 in the polymer network was used. It was formed on the surface of the catalyst by electrolytic polymerization similar to 9. Polyaniline was used as the polymer network, and Nafion 117 (trade name, manufactured by DuPont) was used as the proton conductive polymer. The electrolytic polymerization conditions were the same except that Nafion 117 was used instead of trifluoromethanesulfonic acid. In this way, Nafion 117 in the polyaniline network
Was formed on the surface of the catalyst to obtain a fuel electrode.

Example 9 and Example 10 obtained as described above
The fuel electrode half-cell characteristics of the electrode of No. 2 were measured in the same manner as in Example 4. The limiting current densities of these fuel electrodes were 105 mA / cm ² and 103 mA / cm ² , respectively, and both were polarized. It was confirmed that it has excellent characteristics and high performance.

Example 11 Using the electrode substrate prepared in the same manner as in Example 5, electrolytic polymerization was carried out according to the procedure shown below. The polymer network and the proton conductive monomer were made of the same material as in Example 9. First, the counter electrode and the electrode substrate were placed as working electrodes in an electrolytic cell containing an electrolytic polymerization solution containing a mixed solution of 1 mol / 1 of aniline and 2 mol / 1 of borofluoric acid, the same as in Example 9. Electropolymerization was performed under the conditions. In this way, a polyaniline network film was formed on the surface of the catalyst.

Using the electrode thus obtained and adding 1 vol% of trifluoromethanesulfonic acid to an aqueous solution prepared by adding 1 mol methanol to 1 mol sulfuric acid as a liquid fuel, the fuel cell half-cell characteristics were obtained at 60 ° C. Was measured.
The half-cell characteristics were almost the same as those of Example 7.

Example 12 Using an electrode prepared in the same manner as in Example 11,
As a liquid fuel, a solution obtained by adding 1 vol% of Nafion 117 to an aqueous solution obtained by adding 1 mol methanol to 1 mol sulfuric acid,
The fuel cell half-cell characteristics were measured at 60 ° C. The half-cell characteristics were almost the same as those of Example 8.

As described above, according to the fuel cell of the present invention, the liquid fuel and the oxidant gas can be smoothly supplied without using a pump, a blower or the like. This makes it possible to simplify the system and simplify the structure.
Therefore, it becomes possible to provide a small-sized fuel cell, which has been difficult in the past.

Next, the second embodiment of the present invention relating to the discharge of water produced by the operation of the fuel cell will be described below.

An example of a small fuel cell suitable for the present invention will be shown with reference to the drawings.

FIG. 21 is a perspective view showing an example of the structure of a small fuel cell. Basically, it comprises a fuel cell main body 32, a fuel cartridge 33, a fuel diffusion chamber 34, and a water recovery chamber 35 for facilitating recovery and diffusion of generated water. The details of these components will be described below.

FIG. 22 shows a perspective view of the fuel cell main body 32. The fuel cell main body 32 has a laminated structure in which the power generation units of the fuel cell as shown in FIG. 22 are laminated. Figure 2
As shown in FIG. 2, the fuel cell main body 32 has a structure in which electromotive parts including an electrolyte 36, a fuel electrode 37, and an oxidizer electrode 38 are laminated, and each electromotive part is separated by a separator 39.

The oxidizer electrode 38 is made of a porous material to absorb the generated water. Further, since the fuel electrode 37 also supplies fuel without special power, it is preferable that the fuel electrode 37 has a porous structure to supply liquid fuel such as methanol using the capillary phenomenon in order to miniaturize the fuel cell.

In FIG. 21, 35 is a water recovery chamber,
This is a part for facilitating the recovery of generated water, and a porous body (water recovery wick) is placed in this part.

The water recovery wick is provided in contact with the oxidizer electrode 38. The water recovery wick uses a porous body having an average pore size smaller than that of the oxidizer electrode.

Fuel is supplied using the fuel cartridge 33. FIG. 23 shows a sectional view of the fuel cell shown in FIG. The cartridge 33 is divided into two chambers, a fuel storage space 40 and a water storage space 41, in which fuel (including water as much as necessary) and water generated from the fuel cell main body can be respectively put. A porous body made of an inorganic or organic fiber or the like is previously placed in the interior 41 of the water storage space. The wick in the water recovery chamber 35 has a water storage space 41 in the fuel cartridge when the fuel cartridge is installed.
Be in contact with the 0 water retention wick. At this time, as the water holding wick, a porous body having an average pore size smaller than that of the water recovery wick is used.

With such a structure, the produced water is finally recovered in the fuel cartridge 33. The water recovery chamber 35 does not have to exist independently and can be formed in the structure of the fuel cell body, but in this case as well, the water recovery wick needs to be arranged therein.

On the other hand, when the fuel is also supplied by utilizing the capillarity, the following structure is preferable. A fuel diffusion chamber 34 is provided on the fuel introduction side of the fuel cell body.
Is provided, and a wick made of inorganic or organic fiber is put therein. The wick is in contact with the fuel introduction surface of the fuel electrode, and the fuel supplied from the fuel cartridge is once supplied to the wick of the fuel diffusion chamber 34 and then distributed to the fuel electrode by the action of the capillary tube. The fuel diffusion chamber 34
Does not necessarily have to exist separately from the fuel cell body,
It may be formed in the structure of the fuel cell body. Also,
The fuel diffusion wick does not necessarily have to be arranged, and the liquid fuel may be directly sent to the fuel introduction surface of the fuel cell body.

The fuel cartridge as described above preferably has a structure that can be attached to and detached from the fuel body. When mounted, the fuel storage space and the fuel diffusion wick of the fuel diffusion chamber are in contact with each other to supply the fuel, and at the same time, the water recovery wick of the water recovery chamber and the water holding wick of the water storage space can be in contact with each other. On the contrary, if it is removed,
The structure is such that when the contacts are dropped, the fuel cartridge side and the fuel dispersion chamber side and the water recovery chamber side are shut off, so that they can be shut off from the outside world.

The porous body (wick) used for supplying fuel or collecting water in the above-described form has a structure for sucking the liquid by the action of the capillary, that is, the action of surface tension. The flow of the liquid can be made smooth by arranging the respective porous bodies so that the value of the average pore diameter thereof becomes gradually smaller in the flow direction of the liquid. The smaller the average pore size, the larger the force for pulling the liquid due to the surface tension. Therefore, if the porous bodies are continuously arranged and the average pore diameter of each porous body is gradually reduced, the fluid smoothly flows in that direction.

In this case, for example, regarding the fuel supply path, the average pore diameter of the fuel diffusion wick (inorganic / organic fiber, etc.) is about 100 μm, and the fuel electrode (metal porous body such as nickel) is about 30 μm. On the other hand, regarding the water recovery route, the average pore diameter of the oxidizer electrode (porous metal such as nickel) is set to about 50 μm, and the water recovery wick (inorganic / organic fiber) is set to about 30 μm. With respect to, the flow in the necessary direction can be smoothly performed. The average pore diameter of these wicks can be appropriately changed according to the performance of the fuel cell to be retained.

At this time, the porosity of the porous body is preferably arranged so as to gradually increase in the direction of fluid flow. As the porosity increases, the volume of fluid that can be retained in the porosity increases, and the fluid moving speed can be increased. However, regarding the porous body, the average pore diameter (D), the specific surface area (Sp), and the porosity (E) have a relationship of D = (1 / Sp) · (4E / (1-E)), and It is necessary to select the specific surface area and porosity of the porous body so as to satisfy the relational expression.

In the above-mentioned configuration example of the fuel cell, a small fuel cell in which the recovered water from the oxidant electrode is recovered in the water storage space in the fuel cartridge has been shown. Can be dissipated outside the fuel cell.

FIG. 24 is a perspective view showing an example of the structure of a small fuel cell in the case where the water collected from the oxidizer electrode is dissipated to the outside.

Specifically, it comprises a fuel cell main body 32, a fuel cartridge 33, a water dissipating mechanism 43, and a power unit 44 water recovery chamber 35 (not shown). Further, the pair of positive and negative terminals 42 are arranged at appropriate positions. The fuel cell main body 32 has a stack of g electromotive portions each including a fuel electrode, an oxidizer electrode, and an electrolyte layer shown in FIG.

The water dissipating mechanism 43 accommodates a mechanism for dissipating the water generated at the oxidizer electrode. Motor 44
Contains a power unit or an electronic circuit for operating the water dissipation mechanism. FIG. 25 shows the fuel cell seen from the direction of the fuel cartridge 33 in FIG.
A cross section when cut at a place where is present is shown.

A water recovery chamber 4 is a part for facilitating recovery and diffusion of water generated at the oxidizer electrode, and a porous body (wick) is arranged therein. The water recovery wick has a smaller average pore diameter than the oxidizer electrode and is provided so as to be in contact with the oxidizer electrode in the fuel cell body 32.

The water sent to the water recovery chamber 35 shown in FIG. 25 contains both steam and water, and the abundance ratio varies depending on the operating conditions of the fuel cell. There is no problem with water vapor as it dissipates as it is, and what we are currently talking about is that it is generated in the form of water. The porosity of the porous body (water recovery wick) existing in the water recovery chamber 35 is set to 50% or more, and the water trapped between the pores by the water diffusion mechanism is easily dissipated.

As the water dissipating mechanism 43, a method of providing a small cross-flow fan and operating it to dissipate water can be applied.

Further, instead of the small-sized cross-flow fan, a vibrating element made of a piezoelectric material may be provided and the generated water may be atomized by the vibration.

It is also possible to provide a heater function to heat a part of the generated water to expand the volume thereof, thereby operating the drain valve and forcibly discharging the remaining generated water.

The vibrating element made of a piezoelectric material atomizes the generated water, but does not vaporize it, and thus does not require heat of vaporization. The vibration element itself made of a piezoelectric material can be extremely small and thin. Therefore, the feature of small size and high efficiency is not impaired.

In the method of vaporizing only part of the produced water,
It requires far less energy than vaporizing everything.

Next, FIG. 26 shows a detailed structure of the fuel electrode, the electrolyte layer and the oxidizer electrode which are preferable for smooth operation of the fuel cell having the above-mentioned structure.

Regarding the fuel electrode 37, the fuel introduction surface 45
Is only one of the four side surfaces excluding the stacking direction, and the electrolyte layer 36
A plurality of grooves 46 for letting out carbon dioxide gas are formed in the middle of the plane of the fuel electrode 37 in contact with. The fuel is smoothly carried by the capillaries in the porous body and diffused over the entire surface, and the carbon dioxide gas generated by the reaction is carried to the outside through the groove 46. In this case, in order to prevent the fuel from leaking to the outside, the other three side surfaces 47, 48, 49 which are not supplied with fuel are used.
Close the surface holes of.

On the other hand, the oxidizer electrode 38 is also made of a similar porous material, but in this case, the hole on the surface of the same side surface 50 as the direction of the fuel introduction of the fuel electrode is completely closed, and this surface is completely closed. Prevents fuel from entering. Then, a plurality of grooves 51 are formed in a direction orthogonal to the oxidizer electrode surface on the side in contact with the electrolyte layer 36, and the notches of the grooves reach three side surfaces 52, 53, 54 other than the side surface that closes the holes. Form. This 3
The side surface is for taking in air, and the air is actually taken in from at least two side surfaces. Here, the water generated at the oxidizer electrode is allowed to escape from one side surface (54 in this case) adjacent to the surface blocking the pores of the porous body. The structure in which air is taken in from three sides is to increase the concentration of oxygen and increase the oxidant electrode reaction rate, which is slower than the fuel electrode reaction.

The example of the small fuel cell including the collection and discharge of water generated in the oxidizer electrode of the present invention has been described above. In each of the above examples, the fuel cartridge is used to supply the fuel to the fuel cell body, and the structure is small and suitable for portable equipment.

The required voltage may differ depending on the device, and when a high voltage is required, it is necessary to increase the number of electromotive parts of the fuel cells to be stacked. Alternatively, depending on the device, there is a case where the fuel cell is not enough to be arranged only by an example because of the shape of the power generator. In that case,
As shown in FIG. 27, the fuel supply surface of the fuel cell main body 32 is assembled around the storage position of the fuel cartridge 33, and the fuel diffusion chamber 34 there is installed.
This shortens the fuel supply path and at the same time
The distance from the water recovery chamber 35 is reduced, and a highly reliable power generator can be obtained.

According to the present invention, the water generated on the oxidizer electrode is promptly removed without using any special power, and the operation of the fuel cell can be efficiently continued.

Especially when a solid polymer membrane is used as an electrolyte, the operating temperature is 100 ° C. or lower, and the water produced is almost liquid, but according to the present invention, the water in the liquid state is particularly prompt. Can be removed. Further, even if the fuel cell is moved such as tilted or inverted, the once recovered water can be prevented from splashing and flowing back, and the fuel cell can be small and suitable as a power source for portable equipment.

Further, as described above, the fuel cell using the fuel supply method utilizing the capillary action of the porous body for the fuel supply does not require any special power supply for fuel supply and water discharge. It is possible to make it even smaller.

The invention for achieving the third object of the present invention is provided with an electromotive section having a fuel electrode, an oxidizer electrode and an electrolyte layer sandwiched between these electrodes, and a plurality of electromotive sections are connected in series. The fuel electrode of each electromotive section is supplied with fuel from a common fuel channel and the electrode surface of the fuel electrode of each electromotive section faces the fuel channel, or An oxidant electrode is a fuel cell having a structure in which an oxidant is supplied from a common oxidant channel, and the electrode surface of the oxidant electrode of each electromotive section faces the oxidant channel, wherein the electrolyte layer Is a water-absorbing or water-retaining substance.

A description will be given below with reference to the configuration diagram of the fuel cell shown in FIG.

A fuel electrode and an oxidizer electrode according to the present invention, and an electromotive section having an electrolyte layer sandwiched between these electrodes,
Multiple electromotive units are connected in series, fuel is supplied to the fuel electrode of each electromotive unit from a common fuel channel, and the electrode surface of the fuel electrode of each electromotive unit faces the fuel channel. Or, a fuel having a structure in which the oxidant electrode of each electromotive section is supplied with oxidant from a common oxidant channel and the electrode surface of the oxidant electrode of each electromotive section faces the oxidant channel. The battery means, for example, as shown in FIG. 28, an oxidizer electrode 38, a fuel electrode 37, and an electrolyte layer 60.
The electromotive portions 55 of the adjacent electromotive portions 55 are arranged side by side so that the fuel electrodes are on the same plane.
And a structure in which the oxidizer electrode 38 and the oxidizer electrode 38 are connected in series by connecting with the connecting conductor 57. In the cell having such a structure, the fuel is supplied to the electrode surface of the fuel electrode 37 from the common fuel flow path 58 in both electromotive parts. Air, which is an oxidant, is supplied to the electrode surface of the oxidant electrode 38 from the oxidant channel 59 common to both electromotive parts.

Besides, a fuel cell having a structure in which cylindrical electromotive portions are connected in series can be mentioned. FIG. 29 shows a sectional configuration diagram of another fuel cell according to the present invention. The electromotive portion 55 has a cylindrical shape, and the fuel electrode 37, the electrolyte layer 36, and
An oxidizer electrode 38 is formed.

[0198] One electromotive section 55 is constructed so that the outer oxidant electrode 38 is in contact with the fuel electrode 37 inside another electromotive section. In the fuel cell having such a structure, the fuel is supplied to the fuel flow path 58 formed inside the cylinder and is supplied to the electrode surface of the fuel electrode 37. Air as the oxidant is supplied to the oxidant electrode 38 from the outside of the cylinder. There is also a structure in which the fuel electrode is outside the cylinder, the oxidant electrode is outside the cylinder, and the fuel is supplied from outside the cylinder.

FIG. 44 shows a perspective view of another fuel cell according to the present invention.

One electromotive section 55 has a cylindrical shape, and the fuel electrode 37, the electrolyte layer 36, and the oxidizer electrode 38 are formed from the inside of the cylinder. A plurality of such cylindrical electromotive parts 55,
They are connected in series by the connecting conductor 57. In the fuel cell having such a structure, the fuel is supplied to the fuel flow path 58 formed inside each cylindrical electromotive section, and the fuel electrode 3
7 to the electrode surface. Air, which is the oxidizer, flows from the oxidizer channel 59, which is common to each electromotive section, outside the cylinder, to the oxidizer electrode 3
8 surfaces. Further, in the fuel cell having the structure in which the cylindrical electromotive portions are arranged in this manner, the fuel electrode is arranged outside the same cylinder, and the oxidant electrode is arranged outside the cylinder. There is also a structure in which fuel is supplied from a common fuel flow path.

Conventionally, it is unavoidable to mix water or an electrolyte with a fuel to be supplied to the fuel electrode or a reaction material such as an oxidant to be supplied to the oxidant electrode, since these act as an electrolyte serving as an ion conductive carrier. It has been generally considered that the fuel cell having the above-mentioned structure cannot remove the voltage loss between the plurality of electromotive parts.

As means for solving this problem, in the present invention, in addition to the compound having an ion-exchange ability which is the main constituent substance of an ordinary electrolyte, water is supplied and held in the membrane as the electrolyte layer of the electromotive section. Alternatively, a water-absorbing or water-retaining substance that allows water to pass therethrough according to a concentration gradient is used.

The structure and mechanism of the electrolyte layer used in the fuel cell of the present invention will be described with reference to schematic diagrams. FIG. 30 shows a structural schematic diagram of an electrolyte layer using a proton conductive solid polymer. In FIG. 30, in the electrolyte layer 60, a water-absorbing or water-holding substance 62 is held in a solid polymer electrolyte 61.

FIG. 31 shows a schematic diagram of mass transfer in this electrolyte. As is clear from FIG. 31, the electrolyte layer according to the present invention exhibits the ionic (proton) conductivity inherent in the polymer solid electrolyte, and also exhibits water absorption or water retention by the action of the water absorption or water retention substance, and thus is an oxidizer. It also quickly absorbs water generated on the surface and keeps the electrode in contact with the reactant at all times, and at the same time, it also functions to prevent the inside of the membrane and the surface of the fuel electrode from drying.

That is, the protons generated on the fuel electrode side are
Due to the proton conductivity of the solid polymer electrolyte, the solid polymer electrolyte is transported to the side of the participant electrode (direction of arrow 63). Further, the water generated on the oxidant electrode side is sent to the surface of the fuel electrode and the electrolyte as shown by the arrow 64 by the function of the water absorbing or water retaining substance, and the water is retained.

As described above, since the electrolyte layer according to the present invention exhibits water absorption or water retention by itself, it quickly absorbs the water generated on one of the electrode catalyst surfaces and makes the catalyst surface always in contact with the reactive substance. While being kept, the absorbed water diffuses in the electrolyte according to a concentration gradient, and also has a function of preventing the other electrode surface from drying. Further, in this process, the electrolyte itself also exhibits excellent properties such that effective ion dissociation and ion conduction characteristics can be always maintained without addition of moisture from the outside.

Therefore, in the fuel electrode using this electrolyte layer, water can be supplied into the electrolyte without mixing water in the reactant to be supplied, and the water generated in the oxidizer electrode is promptly absorbed. Therefore, it is possible to suppress the ion conduction in the areas other than the electrolyte layer to be small.

Examples of the water-absorbing or water-retaining substance according to the present invention include starch, acrylonitrile copolymer, water-absorbing polymer compounds such as crosslinked acrylate and crosslinked polyethylene oxide, silica hydrogel, denatured protein (gelatin) gel. Compounds and the like can be used.

[0209] As the electrolyte, the remarkable effect of the present invention can be obtained when the solid polymer electrolyte is used.

As the solid polymer electrolyte, a perfluorocarbon sulfonic acid polymer (trade name: Nafion (manufactured by Du Pont, USA) as a proton conductive solid polymer electrolyte is used.
Examples thereof include polystyrene-based cation exchange membranes having a sulfonic acid group. By using such an electromotive unit,
The substance acting as an electrolyte is not included in any of the reactants supplied to the oxidizer electrode and the fuel electrode, which are the essence of the present invention, in an amount inevitable or more, and the ends of the plurality of electromotive parts are connected in series with each other. A fuel cell having a connected configuration can be realized.

Next, as a method of connecting the ends of a plurality of power generating elements in series with each other, a method of directly connecting the current collector of each power generating element by welding or a conductive adhesive, mixing of reactants and leakage current In order to prevent this, a method of connecting via a conductive plate or the like, or a method of integrally manufacturing a plurality of electromotive parts so as to be connected in series in advance when manufacturing the electromotive part can be adopted.

Further, in these methods, it is also effective to apply water repellent treatment to the connecting portions of a plurality of electromotive sections in order to suppress electrolyte leakage.

Next, the fourth aspect of the present invention will be described below. The present invention directly supplies a carbon-containing fuel such as methanol to the fuel electrode. For example, the present invention relates to a methanol fuel cell for suppressing poisoning on the surface of the fuel electrode when the carbon-containing fuel is supplied to the fuel electrode.

The invention relating to the fourth object of the present application is that a fuel cell comprising a fuel electrode, an oxidant electrode and an electrolyte layer sandwiched between these electrodes is provided with a mechanism for anodically polarizing the fuel electrode. It is a characteristic fuel cell.

That is, in the present invention, when a poisoning product on the surface of the fuel electrode is generated during the operation of the fuel cell, the counter electrode is connected to the fuel electrode and anodically polarized to remove the poisoning product by oxidation. It is a thing. As a result, the fuel cell can obtain a stable output for a long time.

Further, in a normal fuel cell, the fuel electrode,
A plurality of electromotive parts composed of an oxidizer electrode and an electrolyte electrode are connected in series and used. In this case, it is preferable to rotate the polarization operation for each power generation unit. Poisoning products can be removed without interrupting operation.

Examples of the fuel cell of the present invention which achieves the second, third and fourth objects of the present invention will be described below.

Example 13 A power generator using a fuel cell as shown in FIG. 24 was constructed. As a rating, operating voltage 3V6W, capacity of 10h (60W
h). The number of electromotive parts laminated in the fuel cell body is eight. The structure of each electromotive unit is as shown in FIG.

As the solid polymer electrolyte 36, Nafion (trade name) having a thickness of 100 μm was used, platinum catalysts were attached to the surfaces on both sides thereof by electroless plating, and an appropriate amount of a dispersion liquid of PTFE (Teflon) was applied by spraying. . A fuel electrode 37 and an oxidizer electrode 38 having a structure shown in FIG. 22 are arranged from both sides thereof, and a separator 39 made of a nickel plate is used. Both the fuel electrode 37 and the oxidizer electrode 38 are plate-shaped Ni porous bodies. The fuel electrode has a pore size distribution in the range of 40 to 60 μm, and has an average pore size of about 50 μm at the median value. The cathode also has an average pore size of about 50 μm. On the surfaces of the fuel electrode and the oxidizer electrode in contact with the solid polymer electrolyte layer, a platinum catalyst and an appropriate amount of PTF were also used.
E was given. The side surfaces of the oxidizer electrode, the solid polymer electrolyte membrane 36, and the separator 39, which are on the same surface as the fuel impregnated surface of the fuel electrode 37, have alcohol resistance (after closing the holes on the surface of the oxidizer electrode). A protective film was applied to prevent alcohol from entering there. FIG. 25 shows a sectional view of the fuel cell shown in FIG.

The fuel diffusion chamber 34 is made of resin, and a fuel diffusion wick made of a resinous fiber porous body (composite material of fine particles of phenolic resin and polyester woven cloth, average pore diameter of about 100 μm) is put inside this. deep. On the other hand, in the water recovery chamber 35, a water recovery wick made of a resinous porous material (average pore diameter of about 40 μm, porosity of about 50%) of the same material is inserted. A cross flow fan was used as the water dissipation mechanism 43.

The fuel cartridge was charged with methanol: water = 1: 2 in a molar ratio (theoretical 1: 1 but the amount of water was doubled in order to keep the solid polymer electrolyte wet. ).

Comparative Example 2 As Comparative Example 2, the following power generator was constructed. That is, the power generator has the same configuration as that of Example 13, but the oxidizer electrode 38 and the water recovery wick have an average pore diameter of 50 μm.
A fuel cell having a structure using was constructed.

Comparative Example 3 As Comparative Example 3, the following power generator was constructed. That is, a fuel cell having the same structure as that of Example 13, except that the water recovery wick was not attached, was formed.

FIG. 32 shows the result of operating the above battery at room temperature with 2 A discharge. In Comparative Example 2 and Comparative Example 3, the discharge was completed in a short time, and the characteristics according to the rating were not obtained. It is considered that this is because the generated water was not removed from the fuel cell main body fast enough, so that the water stayed and prevented the subsequent reaction.

On the other hand, in Example 13, the discharge according to the rated value was possible. The voltage gradually decreased during discharge, but there was no problem at all. In addition, all the fuel has been used up.

The materials described in the above embodiments are not limited to that alone, and many materials can be used. For example,
The material used for the fuel electrode and the oxidizer electrode is not limited to nickel metal, but an acid resistant material such as a stainless steel material,
Alloys based on aluminum or copper, or valve metal materials such as tungsten and titanium,
Furthermore, a porous body made of a carbon material or a composite material such as SiC may be used. Alternatively, a material in which the surface of the resin porous body is coated with a suitable acid resistant metal or the like may be used. In this case, it is appropriate that the porosity is about 30 to 80% and the average pore diameter is about 1 μm to 100 μm. Below these lower limits, sufficient porosity cannot be realized and the liquid will not impregnate. On the other hand, when the content exceeds the upper limit, the mechanical strength of the material decreases, and the porosity itself becomes too large, which makes it meaningless as a liquid holding material.

Also, as for the wick, various materials can be used, and a substantially hydrophilic material is preferable for carrying the liquid. However, in this case, the material should not be electrically conductive, as this may cause a short circuit junction or a short circuit. The resin is preferably phenol resin, polyester resin, felt such as natural cellulose, non-woven fabric or woven fabric. As for the porosity, the lower limit is preferably about 30% and the upper limit is preferably about 95%.

In this case, below the lower limit, the effective liquid holding amount decreases, and above the upper limit, the liquid holding power decreases, and the wick does not play a role.

Example 14 Solid polymer electrolyte membrane made of commercially available perfluorocarbon sulfonic acid polymer (trade name: Nafion: Du Pont, USA)
(Manufactured by Aldrich) and a water absorbent polymer such as starch and an aqueous solution of a low molecular weight oligomer of sodium polyacrylate polymer were used to form a film. For the membrane formation, both solutions were mixed and developed on a glass plate so that the solid content ratio of the polyelectrolyte and the water-absorbent polymer was 9: 1, and then heat treatment was carried out to complete the polymerization and dry. A catalyst layer made of a mixture of platinum-supporting carbon powder and fluorocarbon and a nickel mesh as a current collector were thermocompression-bonded to both surfaces of this film to form an electromotive section.

In Example 14, four electromotive portions having a size of 10 cm and 3 cm were produced, and the long ends of the electromotive portions were connected via nickel ribbons to produce a plane 4-series power generator. FIG. 33
Shows the outline of this power generator. In FIG. 33, 37 is a fuel electrode, 38 is an oxidizer electrode, 60 is an electrolyte layer made of a solid polymer electrolyte and a water-absorbing polymer, and 57 is a connecting conductor made of a nickel ribbon. FIG. 34 is a cross-sectional view showing a connecting portion between the electromotive portions. In FIG. 34, 37 is a fuel electrode, 38 is an oxidizer electrode, 60 is an electrolyte layer, 56 is a current collector,
57 is a conductor for connection. Teflon dispersion 65 was applied and baked on the connection portion between the current collector 56 and the connection conductor 57 for water repellent treatment. A simulated fuel cell was manufactured using this power generator. A schematic diagram thereof is shown in FIG. First, the generator 66 is housed in the simulated cell container 67, and the air chamber 38, the air inlet 69, the air outlet 70 and the fuel chamber 71, the fuel inlet 72, and the fuel outlet 73 for supplying air and fuel to the both surfaces of the electrode are formed. A simulated fuel cell was prepared. The power generation characteristics were tested by supplying air and fuel to both sides of the electrode.

Example 15 In Example 15, the Teflon dispersion 6 was formed on the entire surface of the connecting portion between the electromotive parts of the power generator manufactured in the same manner as in Example 13.
5 was applied and baked to carry out a water repellent treatment to prepare a simulated fuel cell. FIG. 36 shows a schematic diagram of the connection portion in this case.

Example 16 Further, as shown in FIG. 37, a power generator was prepared in the same manner as in Example 13 except that a nickel mesh was used in common between the two electromotive sections. did.

Table 1 shows the open circuit voltage when hydrogen gas and air were supplied to the fuel chambers of the simulated fuel cells of Examples 14 to 16 and the voltage when 0.2 A / cm ² was applied.

Comparative Example 4 The same simulated fuel cell as in Example 8 was used except that the solid polymer electrolyte did not contain a water-absorbing polymer, and hydrogen gas passed through hot water at 80 ° C. was supplied to the fuel chamber. Other than that, the results of measuring the voltage in the same manner as in Example 13 are also shown in Table 1.

Comparative Example 5 The same power generating element as that used in Examples 12 to 14 was used.
It was cut into a size of cm, and sandwiched between two sheets of porous sintered nickel powder powder to be a positive and negative bipolar chamber. Four sets of these were prepared, and a nickel plate was sandwiched between them to form a simulated fuel cell. Also for this simulated fuel cell, the voltage was measured when hydrogen gas was supplied to the fuel electrode side and air was supplied to the oxidizer electrode side, and Table 1
Shown in.

[0236]

[Table 1] Further, approximate size comparisons were performed for the simulated fuel cells of Example 14 and Comparative Example 4, and the results are shown in Table 2.

[0237]

[Table 2] As described above, in the fuel cell of the present invention, even if the same number of power generation units are stacked, it is better than the conventional stacking method as in the comparative example or the case of supplying the wet reactant which can be the ion source as conventionally performed. It can be seen that it is advantageous because it has a high voltage and is small in volume.

[0238] Furthermore, when the methanol heated to 60 ° C was supplied to the fuel chamber of the simulated fuel cell of Example 14 to directly generate power, and when the same volume of water was added to methanol to perform similar power generation. The voltages are shown in Table 3.

[0239]

[Table 3] As shown in Table 3, it can be seen that the fuel cell operates even when the anode methanol is supplied. Therefore,
It is clear that the fuel cell of the present invention can reduce the voltage loss because it is not necessary to supply water that causes a loss in the voltage between the electrode portions together with the fuel.

Example 17 First, a fuel cell shown in FIG. 38 was prototyped. The electromotive section 74 has a fuel electrode 76 and an oxidizer electrode 77 with the solid polymer electrolyte 75 interposed therebetween.
And a fuel chamber 71 and an air chamber 68 are respectively provided outside thereof. Further, in the fuel chamber 71, a counter electrode 78 for anodically polarizing the fuel electrode is installed. Here, platinum was used for all of the fuel electrode, the oxidizer electrode and the counter electrode, and a commercially available perfluorocarbon sulfonic acid polymer (trade name: Nafion: manufactured by Du Pont, USA) was used for the solid polymer electrolyte. As anolyte, an aqueous solution of 1 mol / 1 of methanol and 1 mol / 1 of sulfuric acid was used.

Using this cell, discharge characteristics were examined at a current density of 20 mA / cm ² . At this time, the discharge is interrupted every 100 minutes and the fuel electrode 76 and the counter electrode 7 are connected to the 2V external DC power source 79.
8 was connected and a polarization operation was performed for 3 minutes to refresh the electrodes.

Comparative Example 6 As a comparison, the discharge characteristics of the samples not subjected to this polarization operation were also examined.

The results are shown in FIG. In Comparative Example 6 in which discharge was continuously performed, the output voltage decreased with the passage of time, whereas in Example 5 in which polarization operation was performed on the way, a high output voltage was maintained even after 1000 minutes. is doing.

Example 18 Comparative Example 7 A battery having 10 cells of the electromotive section of Example 17 was laminated as a prototype. The discharge characteristics of this laminated cell were examined under the same conditions as in Example 17. However, in this case, the refresh operation is
Of the cells being discharged, only one cell was removed from the discharge circuit and polarized so that the remaining cells could continue to discharge, and this operation was rotated in each cell so that the output was not interrupted. In addition, the power source for polarization is taken from the stacked cells so that no external power source is used. The system outline and circuit are shown in FIG.
This figure shows an example in which the No. 3 cell is refreshed. That is, to remove the No. 3 cell from the discharge circuit,
Switch (A) is switched, and further, in order to polarize the fuel electrode of the cell, switch (B) is switched so that No.
4, No. 5, No. Power was taken from 6 cells in parallel and polarized for a certain period of time. Then, this switching operation was rotated in each stacked cell. The polarization is shown in Example 11.
The same procedure as above was performed every 100 minutes for 5 minutes. In addition, the switching circuit in the broken line in the figure can be integrated into an integrated circuit and downsized.

For comparison with the battery thus constructed (Comparative Example 7), the discharge characteristics of the battery not subjected to any polarization operation are shown in FIG.

Similar to the seventeenth embodiment, also in the eighteenth embodiment, a high output voltage is continuously maintained even after 1000 minutes.

[0247]

As described in detail above, according to the present invention,
It is possible to provide a highly efficient fuel cell suitable for miniaturization.

That is, according to the second invention of the object of the present application, water generated on the surface of the oxidizer electrode can be promptly recovered without using special power. Moreover, since the porous body is used for absorption, even if it is used as a movable power source, there is no backflow or scattering of the recovered water. Therefore, the structure is suitable as a power source for small equipment.

According to the third invention of the object of the present application, in a fuel cell of a side-by-side type, a cylindrical type or the like suitable for downsizing, a voltage loss between the invention parts is reduced and a highly efficient power source is provided. Obtainable.

According to the fourth invention of the object of the present application, when a methanol fuel suitable as a fuel for a small fuel cell is used, the poisoning phenomenon on the fuel surface is suppressed and a stable output can be obtained for a long time. A fuel cell can be realized.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing a configuration of a main part of a fuel cell having a separator according to an embodiment of the present invention.

FIG. 2 is a view for explaining a modified example of the channel-combined separator shown in FIG.

FIG. 3 is a partially cutaway perspective view showing a configuration of a main part of another embodiment of a fuel cell having a separator of the present invention.

FIG. 4 is a partially cutaway perspective view showing a configuration of a main part of a fuel cell without a separator according to an embodiment of the present invention.

FIG. 5 is a partially cutaway perspective view showing a main part configuration of another embodiment of the fuel cell in which the separator of the present invention is omitted.

FIG. 6 is a partially cutaway perspective view showing a main part configuration of still another embodiment of the fuel cell in which the separator of the present invention is omitted.

FIG. 7 is a partially cutaway perspective view showing a configuration of a main part of a modified example of the fuel cell shown in FIG.

FIG. 8 is a partially cutaway perspective view showing a main part configuration of a modified example of the fuel cell shown in FIG.

FIG. 9 is a cross-sectional view showing the main configuration of an example in which the fuel cell shown in FIG. 7 is further modified.

FIG. 10 is a partially cutaway perspective view showing a configuration of a main part of a modified example of the fuel cell of the present invention.

FIG. 11 is a partially cutaway perspective view showing a tightening structure for a fuel cell according to the present invention.

FIG. 12 is a diagram schematically showing the configuration of a fuel cell having a tightening structure of the present invention.

FIG. 13 is a diagram schematically showing another example of the fastening structure of the fuel cell according to the present invention.

FIG. 14 is a view showing a modified example of the fastening structure of the fuel cell shown in FIGS. 12 and 13.

FIG. 15 is a view showing still another example of the fastening structure of the fuel cell according to the present invention.

FIG. 16 is a view showing still another example of the fastening structure of the fuel cell according to the present invention.

FIG. 17 is a view showing a modified example of the battery tightening component.

FIG. 18 is a cross-sectional view showing the main configuration of an example of fuel oxidation catalyst particles in the fuel cell of the present invention.

FIG. 19 is a cross-sectional view showing the configuration of the main part of another example of the fuel oxidation catalyst particles in the fuel cell of the present invention.

FIG. 20 is a sectional view for explaining an electrode reaction in a fuel oxidation catalyst used in the fuel cell of the present invention.

FIG. 21 is a perspective view showing the structure of a small-sized fuel cell including a water recovery mechanism of the present invention.

22 is a perspective view of a fuel cell body used in the small fuel cell of FIG.

23 is a cross-sectional view showing the configuration of the small fuel cell of FIG.

FIG. 24 is a perspective view showing the configuration of a small-sized fuel cell including the recovered water dissipation mechanism of the present invention.

FIG. 25 is a cross-sectional view of the small fuel cell of FIG. 21 as viewed from another direction.

FIG. 26 is a perspective view showing configurations of a fuel electrode, an electrolyte layer, and an oxidizer electrode of a small fuel cell including a water recovery mechanism of the present invention.

FIG. 27 is a perspective view showing the configuration of a small-sized fuel cell including the recovered water dissipation mechanism of the present invention.

FIG. 28 is a configuration diagram showing an example of an arrangement configuration of electromotive sections of the fuel cell of the present invention.

FIG. 29 is a configuration diagram showing an example of an arrangement configuration of electromotive sections of the fuel cell of the present invention.

FIG. 30 is a structural schematic diagram of an electrolyte layer.

FIG. 31 is a schematic diagram showing mass transfer in an electrolyte layer.

FIG. 32 is a time-voltage characteristic diagram of the fuel cells according to Example 13 of the present invention and Comparative Examples 3 and 4.

FIG. 33 is a schematic diagram of a power generator according to Example 14.

FIG. 34 is a schematic view of a connecting portion of a power generator according to Example 14.

FIG. 35 is a cross-sectional view of a simulated fuel cell according to Example 14.

FIG. 36 is a schematic view of the connecting portion of the power generator according to the fifteenth embodiment.

FIG. 37 is a schematic view of the connecting portion of the power generator according to the sixteenth embodiment.

FIG. 38 is a circuit diagram showing the configuration of the fuel cell according to Example 17.

FIG. 39 is a time-voltage characteristic diagram of the fuel cell according to Example 17.

FIG. 40 is a circuit diagram showing the structure of a fuel cell according to Example 18.

41 is a time-voltage characteristic diagram of the fuel cell according to Example 18. FIG.

FIG. 42 is a schematic view of a conventional fuel cell.

FIG. 43 is a perspective view showing a laminated structure of a fuel cell.

FIG. 44 is a configuration diagram showing an example of an arrangement configuration of electromotive sections of the fuel cell of the present invention.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Nobukazu Suzuki No. 1 Komukai Toshiba-cho, Sachi-ku, Kawasaki City, Kanagawa Prefecture, Corporate Research & Development Center, Toshiba Corporation (72) Ryoko Kanazawa Komukai-Toshiba, Saiwai-ku, Kawasaki City, Kanagawa Prefecture Town No. 1 Incorporated company Toshiba Research and Development Center (72) Inventor Akinori Motomiya Komukai Toshiba Town No. 1, Komukai-ku, Kawasaki, Kanagawa Prefecture Incorporated company Toshiba Research and Development Center (72) Inventor Yu Kondo Kawasaki, Kanagawa Prefecture Komukai-ku, Toshiba Town, Ltd. 1st, Corporate Research & Development Center, Toshiba Corporation (72) Inventor Ken Uchida, Komukai, Toshiba-cho, Kawasaki City, Kanagawa Prefecture 1st, Corporate Research & Development Center (72) Inventor, Koji Hashimoto Kanagawa 1 Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Japan Inside the Toshiba Research and Development Center, a stock company (72) Inventor Hirokazu Niki, Kawasaki-shi, Kanagawa Komukai-shi, Toshiba Town, R & D Center, Toshiba Corporation (72) Inventor, Kunihiko Sasaki, Komukai-shi, Kawasaki City, Kanagawa Prefecture, 1st, Toshiba Research and Development Center, Ltd. (72), Shinji Tsuruta, Kanagawa 1 Komukai Toshiba-cho, Saiwai-ku, Kawasaki, Japan Stock company Toshiba Research and Development Center

Claims (15)

[Claims] 1. A stack comprising a stack of a plurality of electromotive parts each having a fuel electrode, an oxidizer electrode, and an electrolyte plate sandwiched between these electrodes, wherein a liquid fuel is used as a fuel and an oxidizer gas is supplied to the stack. In a fuel cell configured to flow in a vertical direction along a stacking surface, at least one surface of the outer peripheral surfaces of the stack that includes an end surface of the fuel electrode and is arranged in parallel with the flow of the oxidant gas. Along the direction of the flow of the oxidant gas, a liquid fuel introduction passage is provided at the end surface of the fuel electrode, which is in direct contact with the liquid fuel, and the liquid fuel serves as the fuel electrode. A fuel cell, which is configured to be supplied to the fuel electrode by force. 2. The fuel cell according to claim 1, wherein an oxidant gas supply groove for flowing the oxidant gas in a vertical direction is provided on a surface of the fuel electrode in contact with the oxidant electrode. 3. The fuel cell according to claim 1, wherein the oxidant electrode is provided with an oxidant gas supply groove for flowing the oxidant gas in a vertical direction. 4. The fuel cell according to claim 1, wherein the liquid fuel is introduced from a fuel storage tank by a capillary force of the liquid fuel introduction passage. 5. The fuel cell according to claim 1, wherein an oxide film is formed on a surface of a capillary portion that supplies the liquid fuel to the fuel electrode by a capillary force. 6. The fuel electrode comprises a heat- and acid-resistant support on which a fuel oxidation catalyst is present in an island shape without substantially overlapping each other, and at least a surface of the fuel oxidation catalyst is provided with a heat- and acid-resistant proton conductive material. The fuel cell according to claim 1, wherein the fuel cell is composed of the existing fuel oxidation catalyst particles. 7. A stack comprising a stack of a plurality of electromotive parts having a fuel electrode, an oxidizer electrode, and an electrolyte plate sandwiched between the electrodes, with a separator interposed therebetween, wherein a liquid fuel is used as a fuel, and an oxidizer gas is supplied. In a fuel cell configured to flow in a vertical direction along a stacking surface of the stack, an oxidant gas supply groove for flowing the oxidant gas in a vertical direction is provided on a surface of the separator in contact with the oxidant electrode, and Of the outer peripheral surface of the stack, in a direction orthogonal to the flow of the oxidant gas, along at least one surface including the end surface of the fuel electrode and arranged in parallel with the flow of the oxidant gas. A liquid fuel introduction passage is provided on the end surface of the fuel electrode, the liquid fuel being in direct contact with the end surface, and the oxidant gas is supplied through the oxidant gas supply groove, and the liquid fuel serves as the fuel electrode A fuel cell characterized in that it is configured to supply to the fuel electrode by the capillary force of a porous body. 8. A liquid fuel supply groove having one end opened toward the liquid fuel introduction path is provided on a surface of the separator which is in contact with the fuel electrode.
The fuel cell described. 9. The fuel cell according to claim 7, wherein the liquid fuel is introduced from the fuel storage tank by a capillary force of the liquid fuel introduction passage. 10. The fuel cell according to claim 7, wherein an oxide film is formed on the surface of the capillary portion that supplies the liquid fuel to the fuel electrode by a capillary force. 11. The fuel electrode has a heat- and acid-resistant support on which a fuel oxidation catalyst is present in an island shape without substantially overlapping each other, and at least a surface of the fuel oxidation catalyst is provided with a heat- and acid-resistant proton conductive material. 8. The fuel cell according to claim 7, wherein the fuel cell is composed of the existing fuel oxidation catalyst particles. 12. A fuel cell comprising a stack of a plurality of electromotive parts having a fuel electrode, an oxidizer electrode and an electrolyte plate sandwiched between these electrodes, wherein the stack comprises:
A fuel cell characterized in that at least the stacking direction thereof is clamped with a material exhibiting rubber elasticity. 13. A fuel cell, an electromotive part mainly comprising a fuel electrode, an oxidizer electrode, and an electrolyte layer sandwiched between these electrodes, a fuel supply means for supplying fuel to the electromotive part, and the electromotive part. The water recovery means is configured to collect water generated in the oxidant electrode, and the water recovery means includes first water absorbing means provided in contact with the oxidant electrode for absorbing water generated from the oxidant electrode, and the first water absorbing means. First provided in contact with the water absorbing means
The second water absorbing means is configured to have a larger water absorbing capacity than that of the first water absorbing means. Fuel cell characterized by being 14. A small-sized fuel cell, a plurality of electromotive parts each comprising a fuel electrode, an oxidizer electrode, and an electrolyte layer sandwiched between these electrodes, which are connected in series by a connecting conductor to the fuel electrode of each electromotive part. Fuel is supplied from a common fuel passage, and the electrode surface of the fuel electrode of each power generation unit faces the fuel passage, and the electrolyte layer contains a water-absorbing substance or a water-retaining substance. A fuel cell characterized in that 15. A fuel cell comprising a fuel electrode, an oxidizer electrode and an electrolyte layer sandwiched between these electrodes, wherein the fuel cell has a mechanism for anodically polarizing the fuel electrode. battery.