KR101047699B1 - Method for manufacturing electrolyte-impregnated porous dry electrode for molten carbonate fuel cell - Google Patents

Abstract

The present invention relates to a method for producing an electrolyte-impregnated porous dry electrode for a molten carbonate fuel cell, wherein after manufacturing a porous electrode through an inter powder sintering process, uniformly powder the electrolyte powder formed according to the composition of the process salt on one surface of the electrode. The present invention relates to a method of manufacturing a porous dry electrode for a molten carbonate fuel cell in which an electrolyte is impregnated into a porous electrode by heat dissipating and pressing the electrode to a predetermined pressure and compressing the electrode powder.

Molten Carbonate, Fuel Cell, Stack, Electrode, Electrolyte, Impregnation, Dry Process, Dry Electrode

Description

Method of manufacturing porous electrolyte-filled dry electrodes for molten carbonate fuel cell

The present invention relates to a method for manufacturing an electrolyte-impregnated porous dry electrode for a molten carbonate fuel cell, and more particularly, a fuel cell generated while melting an electrolyte plate during a pretreatment of a fuel cell stack in which unit cells of a molten carbonate fuel cell are stacked. In order to prevent the height change of the stack and to balance the surface pressure uniformly, molten carbonate is impregnated with the electrode in advance by calculating the total amount of electrolyte meeting the specification required for the unit cell of the fuel cell stack without using the conventional electrolyte plate. The present invention relates to a method for manufacturing an electrolyte-impregnated dry electrode of a fuel cell.

Molten carbonate fuel cells are electrochemical generators that produce electricity using hydrogen oxidation and oxygen reduction. Schemes of the hydrogen oxidation and oxygen reduction reaction are shown in the following schemes 1 and 2. That is, electrons are donated while hydrogen is oxidized in the anode, and electrons are donated while oxygen is reduced in the electrode.

_{^{H 2 + CO 3 2 - →}} H 2 O + CO 2 + 2e - ( anode oxidation)

_{CO 2 + 1/2 O 2 + 2e} - → CO 3 2 - ( Cathode reduction reaction)

A typical molten carbonate fuel cell includes a fuel electrode 5, a matrix 4, and an electrode 3 as shown in FIG. 1, and an electrolyte is generally impregnated in the matrix 4 to smooth the flow of ions.

A fuel electrode (5) is provided with a fuel gas such as hydrogen implantation, these and hydrogen-donating electrons as oxide, the electrode 3 is provided with the containing the oxygen or oxygen-air is injected with carbon dioxide, carbonate ions (CO ₃ ^{2 -)} Exhausts the electrons donated from the anode while creating

The carbonate ions move from the electrode 3 to the fuel electrode 5 through a matrix 4 positioned between the fuel electrode 5 and the electrode 3, and electrons flow through an external circuit connected to the fuel cell. Therefore, in the molten carbonate fuel cell, an appropriate electrolyte must be distributed throughout each component, and a sufficient three-phase interface in which the three phases of gas, liquid, and solid meet on the anode 5 and the electrode 3 can produce effective electricity. have.

For this reason, the amount of electrolyte required for the anode 5 and the electrode 3 depends on the size of the fine pores of the anode 5 and the electrode 3, which are set by comparing the theoretical calculations based on capillary forces and the measured values through experiments. It depends on the distribution.

In the conventional molten carbonate fuel cell, an electrolyte plate 4 is inserted between the matrix 4, the anode 5, and the electrode 3, and the electrolyte is melted through heat treatment to be dispersed in each component. In this case, when the fuel cell stack is manufactured by stacking dozens or hundreds of fuel cell unit cells, when the electrolyte plate is melted through heat treatment, the height of the stack is reduced while the space of the electrolyte plate is lost. Furthermore, as the electrolyte plate melts unevenly, a uniform surface pressure distribution cannot be obtained. As the electrolyte plate melts and is pushed out of the fuel cell unit cell, the amount of electrolyte cannot be properly managed.

In order to overcome the above, a method of impregnating an electrolyte with an electrode has been devised. The electrolyte impregnation method of the conventional electrode was a method of directly coating the electrolyte slurry on the electrode to dry and then heat treatment or heat treatment after placing the electrolyte plate on the electrode. However, some problems arise in this case. First, in order to remove organic matter contained in the electrolyte slurry, heat treatment is performed in an oxidizing atmosphere (oxygen or air) maintaining a temperature range of 450 ° C. or lower, and then oxidized in a reducing atmosphere maintaining a temperature range of 450 ° C. or higher. Since the process of reducing the electrode is essential, the continuity of the fuel cell production process is not guaranteed and the organic matter is difficult to remove, resulting in low yield. Second, after the electrolyte is impregnated in the electrode, a severe distortion occurs during the cooling process, resulting in poor flatness of the electrode, which is not suitable for use in a fuel cell stack.

On the other hand, as a patent document on the manufacturing method of the electrode for the molten carbonate fuel cell of the conventional dry process, a metal nickel powder of a predetermined size is prepared in WO03 / 053613 and the powder is arranged by dry ducting (doctoring) Thereafter, a method of manufacturing an anode for MCFC, which is sintered and laminated by sintering the anode support and the anode electrode through pinch rolling, is disclosed.

However, the patent document is a process for the anode only, and nothing is mentioned about the cathode. In addition, the manufacturing process of the anode of the patent document can not precisely control the pore size and porosity, difficult to control the thickness tolerance of the electrode, and also does not include an electrolyte impregnation process.

Accordingly, the present inventors prepared the porous electrode through the powder sintering process during the study in view of the above point, and then uniformly disperses the powder of the electrolyte formed of the powder according to the process salt composition on one surface of the electrode to a constant pressure It has been found that a porous dry electrode for a molten carbonate fuel cell in which an electrolyte is impregnated into a porous electrode may be manufactured by pressing and compressing the electrode powder, followed by heat treatment of the electrolyte powder.

In addition, the method of manufacturing a porous dry electrode for a molten carbonate fuel cell impregnated with the above electrolyte has advantages in that the process is simpler and the manufacturing cost is reduced compared to the wet tape casting technology. The present invention was completed by confirming that surface pressure imbalance and structural problems caused by the solution could be solved.

Accordingly, an object of the present invention is to provide a method for producing an electrolyte-impregnated porous dry electrode for a molten carbonate fuel cell using a dry process.

Another object of the present invention is to provide an electrolyte impregnated porous dry electrode for a molten carbonate fuel cell prepared by the above method.

In order to achieve the above object, the present invention

a) manufacturing a porous dry electrode through a dry casting process, a sintering process and a pressing process of the metal powder;

b) dispersing the electrolyte powder on one surface of the electrode;

c) pressing the electrolyte powder uniformly dispersed on one surface of the electrode to a predetermined pressure to compress the electrode powder; And

d) a method of manufacturing an electrolyte-impregnated porous dry electrode for a molten carbonate fuel cell, comprising the step of heat treatment to impregnate the compressed electrolyte powder into an electrode.

The present invention also provides an electrolyte impregnated porous dry electrode for a molten carbonate fuel cell prepared by the above method.

Hereinafter, the configuration of the present invention will be described for each step.

A) The manufacturing step of the porous dry electrode of the present invention,

Dry casting a metal powder;

Sintering the metal powder; And

Pressing the porous dry electrode manufactured through the sintering; It may include.

In a preferred embodiment of the present invention, the method may further include a step of compressing the metal powder before the step of sintering after the dry casting process.

In the present invention, the dry electrode refers to a porous electrode manufactured by sintering or powder growth between powders using a heat treatment of a metal powder itself, rather than a porous electrode heat-treated a green sheet manufactured by a conventional wet tape casting method.

In a preferred embodiment of the present invention, the step a) of manufacturing a porous dry electrode,

a1) discharging and spreading the metal powder on the graphite support plate;

a2) drycasting the metal powder;

a3) compressing the drycast metal powder;

a4) sintering the compressed metal powder; And

a5) pressing (compressing) the porous dry electrode manufactured through the sintering; It may include.

In a preferred embodiment of the present invention, prior to the a1) step may further comprise the step of installing a jig around the graphite support plate. This is to prevent the dispersed metal powder from leaving the graphite support plate while fixing the graphite support plate when the metal powder is dispersed.

In a preferred embodiment of the present invention, the metal may be selected from the group consisting of nickel, aluminum, chromium, cobalt and combinations thereof, but is not limited thereto.

In a preferred embodiment of the present invention, the a2) drycasting process may be performed by a blade, but is not limited thereto.

In a preferred embodiment of the present invention, the a3) compression process may be performed using a roll, but is not limited thereto. In this case, the applied pressure range may be 50-200 Kgf / cm ² .

In the present invention, the a2) and a3) process is to uniform the thickness of the metal powder and the even surface of the upper side and the gap between the powder.

In a preferred embodiment of the present invention, the a4) sintering process may be carried out at a temperature of 650 ℃ or more, preferably 650 ~ 1050 ℃, 30 minutes or more, preferably 30 minutes to 3 hours under a reducing atmosphere Can be done. This is to achieve the bonding between the powders.

In a preferred embodiment of the present invention, the a5) pressing (compression) process can be carried out at a pressure of 50-200Kgf / cm ² . This is a process for controlling the thickness unevenness of the porous electrode due to the sintering phenomenon.

In a preferred embodiment of the present invention, the thickness tolerance can be controlled to within 10 mu m through such compression under pressure.

In the present invention, the b) dispersing the electrolyte powder is a step of uniformly dispersing the powder of the electrolyte formed of the powder in accordance with the process salt composition or the cyclic lithium electrolyte composition on one surface of the electrode.

In a preferred embodiment of the present invention, the step b) dispersing the electrolyte powder, b1) the graphite support plate for mounting the electrode, and is formed to be continuous to the one end and the other end of the graphite support plate vertically and vertically It may include the step of fixing the electrode through the graphite jig for fixing the side end.

The fixing step of the electrode is to fix the electrode at a predetermined position when the electrolyte powder is dispersed to prevent the dispersed electrolyte from being separated from one surface of the electrode.

In addition, in the preferred embodiment of the present invention, the step of b) dispersing the electrolyte powder, b2) causing a constant vibration with the built-in vibrator and moving the electrolyte powder from one end of the electrode to the other end on one surface of the electrode Dispersing the electrolyte through a dispersion device for uniformly dispersing to one surface of the electrode.

In a preferred embodiment of the present invention, the step of c) pressing the electrolyte powder on the electrode may be performed by pressing the electrolyte powder on one surface of the electrode using a c1) pressing roller.

The pressure at the time of pressing using the pressing roller is preferably 1.0 kgf / cm ² or less, more preferably in the range of 0.1-0.5 kgf / cm ² .

In a preferred embodiment of the present invention, the step of c) pressing the electrolyte powder on the electrode may include c2) mounting a graphite plate on the electrolyte powder pressed on one surface of the electrode.

In a preferred embodiment of the present invention, the graphite plate may have a density of 1.75-1.9 gm / cc and a thickness of 20 mm or more.

In a preferred embodiment of the present invention, the step d) is a step of melting the electrolyte powder pressed on one surface of the electrode in a reducing atmosphere in a heat treatment furnace forming a temperature range of 500 ℃ to 650 ℃ to impregnate the electrode It may include.

In the present invention, the electrolyte powder preferably has a diameter of 10 µm or less.

In a preferred embodiment of the present invention, the electrolyte powder may be formed of any one of the composition of lithium carbonate and potassium carbonate or lithium carbonate and sodium carbonate.

In a preferred embodiment of the present invention, the composition of the lithium carbonate: potassium carbonate may range from molar ratio 50:50 to molar ratio 90:10.

In a preferred embodiment of the present invention, the composition of the lithium carbonate: sodium carbonate may range from molar ratio 50:50 to molar ratio 90:10.

In the present invention, the electrolyte powder is preferably used after primary melting of any one of the compositions of lithium carbonate and potassium carbonate or lithium carbonate and sodium carbonate, followed by cooling and regrinding. This is because a high temperature of 650 ° C. or higher is required for uniform melting when two kinds of carbonate salts are mixed and pressed and placed on one surface of the electrode to be melted in a heat treatment furnace.

In a preferred embodiment of the present invention, the electrolyte powder is a raw material of Rb, Cs, Gd, Ca, Sr, Ba, or Mg in an electrolyte prepared by the composition of any one of lithium carbonate and potassium carbonate, or a composition of lithium carbonate and sodium carbonate. The mixed salt in which the caponate salt is added to 15 mol% or less, more preferably in the range of 1 to 15 mol% and mixed uniformly.

In a preferred embodiment of the present invention, the electrolyte powder is a raw material of Rb, Cs, Gd, Ca, Sr, Ba, or Mg in an electrolyte prepared by the composition of any one of lithium carbonate and potassium carbonate, or a composition of lithium carbonate and sodium carbonate. The caponate salt may be added in an amount of 15 mol% or less, more preferably in the range of 1 to 15 mol%, followed by primary melting, followed by regrinding.

In addition, the electrolyte-impregnated porous dry electrode of the present invention has a thickness of 0.7 mm or less in the case of an anode, preferably in the range of 0.1 to 0.6 mm, and 0.6 mm or more, preferably 0.6 in the case of a cathode. It is preferable to form in the range of 1.0 mm. This is because the total pore volume is determined according to the thickness of each electrode in order to provide enough electrolyte amount for one unit cell of the stack with only the electrolyte impregnated in the anode and the cathode.

Hereinafter, each step of the method of manufacturing an electrolyte-impregnated porous dry electrode of a molten carbonate fuel cell according to an embodiment of the present invention will be described in detail.

2 is a cross-sectional view showing the configuration of a fuel cell unit cell including an electrode 30 manufactured according to the electrolyte-impregnated porous dry electrode manufacturing method of a molten carbonate fuel cell according to an embodiment of the present invention.

Referring to FIG. 2, the fuel cell unit cell includes a fuel electrode 60 that provides electrons as hydrogen is oxidized, an electrode 30 that consumes electrons as oxygen is reduced, and an ion between the electrode 30 and the fuel electrode 60. Matrix 50 for inducing a smooth exchange of the electrode, an electrode current collector plate for forming a flow path of a gas supplied to the electrode 30, and an electrode current collector plate for collecting charges generated from the electrode 30 ( 10), a fuel electrode-current collector plate gas passage 70 for forming a flow path of gas supplied to the fuel electrode 60, and a fuel-electrode current collector plate 80 for collecting charges generated in the fuel electrode 60.

The fuel cell unit cell of FIG. 2 does not include the electrolyte plate 8 (refer to FIG. 1) included in the conventional fuel cell unit cell shown in FIG. 1. This is because the electrolyte is impregnated in advance in the electrode 20 and heat treated. Therefore, even if the stack is formed by stacking dozens or hundreds of fuel cell unit cells of FIG. 2, the height of the stack does not change even when the stack is heat-treated. The required amount of electrolyte is spread evenly. As a result, it is possible to prevent a change in thickness and uneven surface pressure distribution of the fuel cell unit cell generated when the electrolyte plate is melted as a problem according to the prior art.

Among the components of the fuel cell unit cell illustrated in FIG. 2, an electrode current collector plate 10, an electrode current collector plate gas passage 20, a fuel electrode current collector plate gas passage 70, and a fuel electrode current collector plate 80 may be used. The same components, which are included in a general fuel cell unit cell, will not be described in detail. Since the technical idea of the present invention is a method of manufacturing a fuel cell unit cell, and a method of pre-impregnating a required electrolyte in an electrode 30, a part related thereto will be described in detail.

The electrolyte-impregnated porous dry electrode manufacturing method of the molten carbonate fuel cell according to the embodiment of the present invention consists of six steps. First, dry casting step for dispersing metal powder and uniformity of powder pore, second, manufacturing electrode through sintering process, third, using press to control thickness tolerance of electrode, fourth, process on one side of electrode Uniformly dispersing the electrolyte formed of the powder in accordance with the salt composition; fifth, pressing the electrolyte powder uniformly dispersed on one surface of the electrode to a predetermined pressure to compress the electrode, and sixth, heat treating the electrolyte powder compressed to the electrode. Impregnating the electrode through the.

Hereinafter, a method necessary for each step and use of a device required to perform each method will be described in detail with reference to FIGS. 3 to 6.

In the present invention, the sintering process is to put the solid powder into a certain mold and pressurized with a press, and then heated to a temperature close to the melting point of the solid powder so that each solid powder is deposited or bonded in contact with each other into a single mass. Say the process of making. In general, it is the same process that is suitable for making solids with appropriate voids. The electrode 30 is prepared in advance through this sintering process.

Referring to FIG. 3, the electrolyte 90, which is formed of powder according to a predetermined composition, is uniformly dispersed on one surface of the dry porous electrode 30 manufactured through the sintering process. Electrolyte 90 powder is laminated on one surface of the electrode 30 to a predetermined thickness.

According to an embodiment of the present invention, eutectics of lithium carbonate (Li ₂ CO ₃ ) and potassium carbonate (K ₂ CO ₃ ) is Li ₂ CO ₃ : K ₂ CO ₃ = 62 mol%: 38 mol%, and eutectics of lithium carbonate (Li ₂ CO ₃ ) and sodium carbonate (Na ₂ CO ₃ ) are Li ₂ CO ₃ : K ₂ CO ₃ = 53 mol%: 47 mol% .

In the present invention, the high lithium carbonate electrolyte means that the composition ratio of lithium carbonate in the process salt composition is in the range of 62 mol% to 72 mol%. Each composition can be set by the designer calculating the amount of electrolyte required.

According to an embodiment of the present invention, the electrolyte 90 powder is formed to a diameter of 10 micrometers or less in order to improve adhesion with the electrode 30.

In addition, according to an embodiment of the present invention, the electrolyte 90 powder mixed according to the process salt composition is used after removing impurities while maintaining a vacuum degree of about 10 ⁻² torr in a vacuum furnace of 200 ° C. or higher.

In order to uniformly disperse the powder of the electrolyte 90 onto one surface of the electrode 30, the electrode must first be fixed at a predetermined position. Accordingly, as shown in FIG. 3, the electrode 30 is continuously formed perpendicular to one end and the other end of the graphite support plate 100 and the graphite support plate 100, which can mount the electrode 30. It is fixed through the graphite jig 110 to fix one end and the other end.

The graphite support plate 100 performs a function of supporting the electrode 30 while the electrode 30 is mounted, and the graphite jig 110 performs a function of preventing the electrode from being separated from the graphite support plate 100. In addition, the electrolyte 90 powder dispersed in the electrode 30 through the graphite support plate 100 and the graphite jig 110 may be prevented from being separated from one surface of the electrode 30, and the electrolyte 90 powder may be prevented. It helps to be evenly distributed on one surface of the electrode (30).

In the method of dispersing the powder of the electrolyte 90 onto one surface of the electrode 30, it is preferable to use the dispersing device 130 shown in FIGS. 4 and 5.

The dispersing device 130 has a vibrator 131 is built in to generate a vibration at a constant cycle. In addition, the electrolyte 90 powder is injected into the dispersing device 130, and an outlet (not shown) through which the electrolyte 90 powder can be discharged is formed on the lower surface of the dispersing device 130, thereby dispersing the device 130. Will discharge the electrolyte 90 powder while causing a constant vibration (see down arrow in FIG. 5).

In addition, the dispersing apparatus 130 uniformly disperses the electrolyte 90 powder onto one surface of the electrode while moving from one end of the electrode 30 to the other end. Dispersing device 130 is preferably located at a suitable height on one side of the electrode 30, although not shown in the figure, is coupled to a certain guide rail on one side of the electrode 30 is designed to move on one side of the electrode 30 It is preferable to be.

4 and 5 show a schematic view of the disperser 130. The components of the disperser 130 are general and detailed description thereof will be omitted. This is because the technical idea of the present invention lies in a method of uniformly dispersing the powder of the electrolyte 90 through the movement and vibration of the dispersing apparatus 130.

Referring again to FIG. 4, the electrolyte 90 powder dispersed at a predetermined thickness on one surface of the electrode 30 through the dispersing device 130 may be adhered to the electrode 30 by the pressing roller 120 again. Squeezed. The applied compressive load is such that a compressive load of 0.5 Kgf / cm ₂ or less is applied. This is because applying a higher applied load causes a thickness reduction due to compression deformation of the electrode. Compression roller 120 is also shown in schematic in FIG. Compression roller 120 may be provided manually or coupled to a fixed guide rail and automatically driven by a motor.

Although not shown in the drawing, a graphite plate having a constant load on the surface of the electrode 90 having a constant load so that a constant pressure may be applied to the powder of the electrolyte 90 pressed onto the electrode 30 through the pressing roller 120. ) Mount on powder. The graphite plate additionally compresses the electrolyte 90 powder to the electrode 30, and is thermally treated in a state where the graphite plate is placed, whereby the powder of the electrolyte 90 is reduced by the pressure of the reducing gas injected during the heat treatment. To prevent deviation from In addition, the graphite plate not only has good thermal conductivity but also prevents rapid cooling of the electrolyte impregnated electrode when it comes out of the heat treatment furnace, and has a function of eliminating distortion and crack generation caused by density differences. Therefore, the size of the graphite plate should preferably be corresponding to the electrode or provided in a slightly larger size. In either case, the graphite plate should be able to cover all of the electrolyte 90 powder dispersed on one surface of the electrode 30. The graphite plate is preferably formed to a density that can have a constant load and is formed to a thickness of about 10 mm.

In the state where the graphite plate is applied, the electrode 30 in which the electrolyte 90 powder is dispersed in the continuous furnace (not shown) for heat treatment is fixed by the graphite support plate 100 and the graphite jig 110. Is committed. The heat treatment melts the powder of the electrolyte 90 pressed on one surface of the electrode 30 in a reducing atmosphere in a heat treatment furnace (not shown) forming a temperature range of 550 ° C. to 650 ° C. to impregnate the electrode 30. Reducing gas is injected into the heat treatment furnace. The reducing gas is a mixed gas of hydrogen and nitrogen, the mixing ratio of hydrogen and nitrogen is 95: 5 Vol.%.

Since the porosity of the electrode 30 formed through the sintering process is generally between 50% and 80%, in order to impregnate the electrolyte with 20% to 100% of the total pore volume, the thickness of the electrode is 0.7 mm or less. In the case of the air electrode, it is preferable that the air electrode be formed to be 0.8 mm or more.

According to the method of manufacturing an electrolyte-impregnated dry electrode of a molten carbonate fuel cell of the present invention, since the dry dry casting method is used instead of the wet tape casting process, the process is simple and the manufacturing cost can be reduced, and the electrolyte plate is not used. Since it does not cause height change of the molten carbonate fuel cell stack, it is possible to obtain a uniform surface pressure distribution, thereby ensuring mechanical stability, and the electrolyte required for each component can be sufficiently supplied only by the electrolyte impregnated with the electrode. Instability at the time of lamination can be excluded. In addition, since the electrolyte can be slowly and evenly dispersed during the process of raising the temperature to the operating temperature, high performance can be seen. Furthermore, since there is no addition of organic matter, there is no need for separate organic matter removal process, so it is possible to continuously process in a continuous atmosphere of a reducing atmosphere and to minimize distortion during the cooling process.

Hereinafter, the configuration and effects of the present invention will be described in more detail with reference to examples, but these examples are merely illustrative of the present invention, and the scope of the present invention is not limited only to these examples.

Example  1: electrolyte Impregnation type  Porous dry electrode ( Cathode Manufacturing

The method of manufacturing an electrolyte-impregnated dry cathode (air electrode) for molten carbonate fuel cell according to the present embodiment was as follows (see FIG. 6).

This embodiment is an example of manufacturing an electrolyte impregnated dry cathode for a molten carbonate fuel cell based on the electrolyte impregnated porous dry electrode manufacturing method. As a raw material of the dry cathode, a filament-type nickel powder manufactured by INCO Co., Ltd. was used, and dried at 120 ° C. for more than 24 hours in order to improve the flowability of the nickel powder. In addition, an alloy powder in which a PVA-based binder is coated on nickel powder or mixed with different kinds of powders may be used.

The perfectly dried nickel powder was spread widely on the horizontally maintained graphite plate through a hopper, and then a 1.4 mm thick powder plate was made using a multi-stage blade. At this time, in order to prevent the crack of the powder during the process using the blade, the angle of the blade blade was set within 10-50 degrees, the blade blade was designed to be inclined more than 10 degrees in the advancing direction.

The 1.4 mm thick powder plate was compacted through the rearrangement of the powder and compressed to 1.2 mm in order to make the pores uniform between the powders. At this time, the compression method using the uniaxial hydraulic press was also possible. Through the pore homogenization and rearrangement of the powder, pore size control along with pore size control was possible.

Thereafter, the dry-cast and powder-compressed powder plate was heat-treated and sintered together with the graphite plate in a reducing atmosphere (N ₂ : H ₂ = 95%: 5%) at 750 ° C. for 30 minutes to prepare an electrode plate. Although the pore size and porosity of the electrode are controlled by the variables of sintering temperature and time, the variation tends to be weak.

The thickness tolerance of the electrode was controlled by the uniaxial hydraulic press for the electrode whose thickness is not uniform after baking. After installing the guard of 0.93mm was pressed for about 10 minutes at a pressure of about 200Kg / ㎠, the thickness of the electrode after compression showed a thickness of 0.93mm ± 10㎛.

After spreading the electrode powder powder fired widely spread evenly through the blade device. The electrolyte powder had a weight of 75 vol.% Based on the metal pore volume of 650 ° C.

The metal powder plate and the electrolyte powder were heat-treated together with the graphite plate under a reducing atmosphere. In order to uniformly distribute the electrolyte, the metal powder plate and the electrolyte powder were heat-treated at 650 ° C. for 5 hours to prepare an electrode plate impregnated with the electrolyte.

The electrolyte-impregnated dry cathode of the molten carbonate fuel cell according to the present embodiment prepared as described above was made to have a thickness of 0.9 mm and showed uniform flatness without distortion while having a uniform electrolyte distribution.

Figure 7 shows the size distribution of pores of the metal electrode plate after the extraction of the electrolyte in the electrolyte impregnated dry cathode according to this embodiment. At this time, it can be seen that the pore size of about 8 to 9 micrometers.

Experimental Example 1: Characteristics of the porous dry electrode according to the present invention

In order to confirm the characteristics of the porous dry electrode according to the present invention, the porosity of the dry electrode after extracting and removing the electrolyte from the electrolyte-impregnated porous dry electrode prepared in Example 1 was measured using the ASTM C-373 method , Pore size was measured.

As shown in Table 1, the electrode thickness of the porous dry electrode according to the present invention was about 0.9mm and the thickness tolerance of the electrode was controlled to about 10㎛, showing a uniform pore size of 9㎛ on average over the entire area of the electrode And porosity of 81%.

electrode Porosity Pore size thickness Thickness tolerance Electrolytic Impregnation Dry cathode 81% 8㎛ 0.9mm ± 10㎛ 75Vol.%

As described above through the above Examples and Experimental Examples, the present invention is to produce a porous electrode through the powder sintering process and then uniformly disperse the powder of the electrolyte formed of the powder in accordance with the composition of the process salt on one surface of the electrode It is a very useful invention in the fuel cell industry because it is possible to provide a porous dry electrode for a molten carbonate fuel cell in which the electrolyte is impregnated into the porous electrode by heat-treating the electrolyte powder pressed to the electrode by pressing under pressure.

1 is a block diagram of a molten carbonate fuel cell unit cell according to the prior art.

2 is a configuration diagram of a molten carbonate fuel cell unit cell to which an electrode manufactured by the electrolyte-impregnated electrode manufacturing method of a molten carbonate fuel cell according to the present invention is applied.

Figure 3 is a schematic diagram showing the electrolyte powder dispersion method according to the present invention.

Figure 4 is a schematic diagram showing a pressing method for improving the adhesion of the electrolyte powder and the porous electrode according to the present invention.

FIG. 5 is a schematic view showing a dispersion device for dispersing the electrolyte powder of FIG. 3 in a porous electrode.

6 is a flowchart schematically illustrating a method of manufacturing an electrolyte-impregnated porous dry cathode (air electrode) of a molten carbonate fuel cell according to an embodiment of the present invention.

Figure 7 is a graph showing the results of examining the pore distribution of the electrolyte-impregnated porous dry electrode according to an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

10: electrode current collector plate 20: electrode current collector plate gas flow path

30 electrode 50 matrix

60: fuel electrode 70: fuel electrode current collector plate gas flow path

80: anode current collector plate 90: electrolyte

100: graphite support plate 110: graphite jig

120: pressing roller 130: dispersion device

131: vibrator

Claims (16)

a) manufacturing a porous dry electrode through a dry casting process, a sintering process and a pressing process of the metal powder; b) dispersing the electrolyte powder on one surface of the electrode; c) pressing the electrolyte powder uniformly dispersed on one surface of the electrode to a predetermined pressure to compress the electrode powder; And d) heat treating the compressed electrolyte powder to impregnate the electrode; The electrolyte powder is an electrolyte-impregnated porous dry electrode for molten carbonate fuel cell, wherein the electrolyte of lithium carbonate and potassium carbonate or lithium carbonate and sodium carbonate is melted first, then cooled and then pulverized. Method of preparation. The method of claim 1, wherein the step a) of preparing a porous dry electrode, a1) discharging and spreading the metal powder on the graphite support plate; a2) drycasting the metal powder; a3) compressing the drycast metal powder; a4) sintering the compressed metal powder; And a5) pressing (compressing) the porous dry electrode manufactured through the sintering; Method for producing an electrolyte-impregnated porous dry electrode for molten carbonate fuel cell comprising a. The method of manufacturing an electrolyte-impregnated porous dry electrode for molten carbonate fuel cell according to claim 2, further comprising a step of installing a jig around the graphite support plate prior to the step a1). The method of claim 2, wherein the a4) sintering the compressed metal powder is performed at a temperature of 650 to 1050 ° C. The method of claim 2, wherein the a5) pressing process is performed to control the thickness tolerance of the sintered electrode to ± 10 μm. The method of claim 1, wherein b) dispersing the electrolyte powder is formed on the graphite support plate on which the electrode is mounted, and is perpendicular to one end and the other end of the graphite support plate, and fixes one end and the other end of the electrode. The method of manufacturing an electrolyte impregnated porous dry electrode for a molten carbonate fuel cell, characterized in that it comprises the step of fixing the electrode through a graphite jig. The method of claim 1, wherein b) dispersing the electrolyte powder, b2) causing a constant vibration with a built-in vibrator and moving the electrolyte powder from one end of the electrode to the other end on one surface of the electrode And dispersing the electrolyte through a dispersing device that is uniformly dispersed in a molten carbonate fuel cell. The method of claim 1, wherein the step of pressing the electrolyte powder on the electrode c1) the electrolyte container for molten carbonate fuel cell, characterized in that can be carried out by pressing the electrolyte powder on one surface of the electrode using a pressing roller. Method for producing acicular porous dry electrode. 2. The electrolyte container of claim 1, wherein the c) compressing the electrolyte powder onto the electrode comprises c2) mounting a graphite plate on the electrolyte powder compressed on one surface of the electrode. Method for producing acicular porous dry electrode. The method of claim 1, wherein the d) heat treating comprises melting the electrolyte powder compressed on one surface of the electrode in a reducing atmosphere in a heat treatment furnace forming a temperature range of 500 ° C. to 650 ° C., and impregnating the electrode powder. Method for producing an electrolyte impregnated porous dry electrode for molten carbonate fuel cell, characterized in that. The method of claim 1, wherein the electrolyte powder has a diameter of 10 µm or less. delete delete The method of claim 1, wherein the electrolyte powder is made of lithium carbonate and potassium carbonate or an electrolyte of any one of lithium carbonate and sodium carbonate. A method for producing an electrolyte-impregnated porous dry electrode for a molten carbonate fuel cell, characterized in that the mixed salt is added uniformly mixed with the caponate salt in the range of 1 to 15 mol%. The method of claim 1, wherein the electrolyte powder is made of lithium carbonate and potassium carbonate or an electrolyte of any one of lithium carbonate and sodium carbonate. A method for producing an electrolyte-impregnated porous dry electrode for molten carbonate fuel cell, characterized in that the caponate salt is added in the range of 1 to 15 mol%, followed by primary melting. The molten carbonate fuel according to claim 1, wherein the electrolyte-impregnated porous dry electrode manufactured by the above method has a thickness of 0.1 to 0.6 mm in the case of the anode and a thickness of 0.6 to 1.0 mm in the case of the cathode. Method for producing an electrolyte-impregnated porous dry electrode for batteries.

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