JP2003017072A - MEA FOR FUEL CELL, METHOD FOR MANUFACTURING THE SAME, AND CATALYST LAYER FOR FUEL CELL, AND METHOD FOR MANUFACTURING THE SAME - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an MEA for a fuel cell capable of reducing the electric resistance of a junction between an electrode catalyst layer and an electrolyte membrane, a method for manufacturing the same, and a catalyst layer for a fuel cell and a method for manufacturing the same. SOLUTION: (1) A method for manufacturing a fuel cell MEA1 in which a catalyst layer is formed by a sol-gel method, an electrolyte membrane is formed by a sol-gel method, and the electrolyte membrane and the catalyst layer are integrally formed when the sol-gel method is used. M for fuel cell
EA1. (2) A method for producing a catalyst layer 12 for a fuel cell, in which a substrate for supporting a catalyst is immersed in a sol-gel solution in which a catalyst colloid is dispersed in a solvent containing a proton-conducting substance as a component, and the surface is coated and gelled, and the fuel thereby is used. Battery catalyst layer 1
2. (3) A method for manufacturing a fuel cell catalyst layer and a fuel cell catalyst layer in which a water-repellent layer is formed on the surface and then immersed in a sol-gel solution containing a water-repellent substance as a component to form a water-repellent layer on the outermost surface. (4) The MEA 1 was formed in a pipe shape. (5) The current collector 2 was a wire or a mesh.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an MEA for a fuel cell.
The present invention relates to a method for producing the same, a catalyst layer for a fuel cell, and a method for producing the same.

[0002]

2. Description of the Related Art A solid polymer electrolyte fuel cell has a membrane-electrode assembly (MEA).
y) and a separator (current collector) to form a cell, a plurality of cells are laminated to form a module, the modules are laminated to form a module group, and terminals, insulators, and End plates are arranged to form a stack, and a fastening member that extends in the stack direction of the cell stack outside the stack (for example,
Tension plate) is used for tightening and fixing. The membrane-electrode assembly includes an electrolyte membrane composed of an ion exchange membrane, a catalyst layer arranged on one surface of the electrolyte membrane and an electrode (anode, fuel electrode) composed of a diffusion layer, and a catalyst layer arranged on the other surface of the electrolyte membrane. It is composed of an electrode (cathode, air electrode) composed of a diffusion layer. Fluid passages are formed in the cell for supplying fuel gas (anode gas, hydrogen) and oxidizing gas (cathode gas, oxygen, usually air) to the anode and cathode. In the solid polymer electrolyte fuel cell, hydrogen is converted into hydrogen ions and electrons on the anode side, the hydrogen ions move to the cathode side in the electrolyte membrane, and oxygen, hydrogen ions and electrons (on the anode of the adjacent MEA) move on the cathode side. Water is generated from the electrons generated in (1) come through the separator). Anode side: H ₂ → 2H ⁺ + 2e ⁻ Cathode side: 2H ⁺ + 2e ⁻ + (1/2) O ₂ → H ₂ O JP-A-5-182672 discloses a method for manufacturing a MEA for a fuel cell. . In the method of manufacturing an MEA for a fuel cell disclosed in JP-A-5-182672, the electrodes and the electrolyte membrane are hot pressed.

[0003]

However, in the method for manufacturing a MEA for a fuel cell by hot pressing the electrode and the electrolyte membrane, the contact electric resistance at the junction between the electrode layer and the electrolyte membrane is large, and the single cell and There is a problem that the output of the stacked fuel cells cannot be obtained sufficiently. The purpose of the present invention is to
To provide an MEA for a fuel cell, a method for producing the same, a catalyst layer for a fuel cell, and a method for producing the same, which can reduce the electric resistance of a joint portion between an electrode catalyst layer and an electrolyte membrane as compared with a conventional method such as hot pressing. It is in.

[0004]

The present invention which achieves the above object is as follows. (1) A fuel cell ME in which a catalyst layer is produced by a sol-gel method, an electrolyte membrane is produced by a sol-gel method, and the electrolyte membrane and the catalyst layer are integrally formed during production by the sol-gel method.
Manufacturing method of A. (Embodiments 1 and 5 of the present invention) (2) A catalyst layer manufactured by a sol-gel method and an electrolyte layer manufactured by a sol-gel method are provided, and the catalyst layer and the electrolyte layer are manufactured by a sol-gel method. MEAs for fuel cells that are sometimes integrally molded. (Embodiments 1 and 5 of the present invention) (3) The catalyst-supporting base material is immersed in a sol-gel solution in which a catalyst colloid is dispersed in a solvent containing a proton-conductive substance as a component, and the catalyst-supporting base material is pulled up to form the catalyst-supporting base material. A method for producing a catalyst layer for a fuel cell, which is surface-coated with a sol-gel solution and gelated. (Embodiment 1 of the present invention) (4) The catalyst layer for a fuel cell according to (3), wherein the sol-gel solution contains a water-repellent substance as a component in advance in addition to the proton conductive substance. (Embodiment 1 of the present invention) (5) For supporting a catalyst by immersing the catalyst supporting substrate in a sol-gel solution in which a catalyst colloid is dispersed in a solvent containing a proton conductive substance as a component and not containing a water repellent substance, and pulling it up A method for producing a catalyst layer for a fuel cell, wherein a substrate is surface-coated with the sol-gel solution to form a gel, which is then immersed in a sol-gel solution containing a water-repellent substance as a component to form a water-repellent layer on the outermost surface. (Embodiment 2 of the present invention) (6) A catalyst-supporting base material carrying a catalyst in advance is dipped in a sol-gel solution containing a proton conductive substance as a component, and the catalyst-supporting base material carrying the catalyst is prepared as described above. A method for producing a catalyst layer for a fuel cell, which is surface-coated with a sol-gel solution and gelated. (Embodiment 5 (1) of the present invention) (7) The catalyst layer for a fuel cell according to (3) or (4) or (5) or (6), wherein the catalyst supporting substrate is a carbon fiber sheet. Manufacturing method. (Embodiments 1, 2, and 5 of the present invention) (8) The catalyst-supporting substrate is an ammonia gas in which carbon fiber is immersed in titania sol or titania + catalyst sol and the surface is titania gel-coated or titania + catalyst gel-coated. Alternatively, the surface of TiN is burned in a nitrogen atmosphere.
Alternatively, the method for producing a catalyst layer for a fuel cell according to (3), (4), (5) or (6), which comprises a fiber sheet formed with catalyst-containing TiN. (Embodiment 3 of the present invention) (9) The catalyst-supporting base material is Au on a part of carbon fiber.
The method for producing a catalyst layer for a fuel cell according to (3), (4), (5) or (6), which comprises a sheet in which wires are woven. (Embodiment 4 of the present invention) (10) A fuel cell catalyst layer produced by the method according to any one of the above (3) to (9). (Embodiment 1 of the present invention
~ 4) (11) When the electrolyte membrane is prepared, the
-Adding glycidoxypropyltrimethoxysilane,
The method for producing an MEA for a fuel cell according to (1), wherein an acrylic container is used as the gelling container. (Embodiment 6 of the present invention) (12) The MEA for a fuel cell according to claim 2, wherein the MEA is formed in a hollow cylindrical shape. (Embodiment 7 of the present invention) (13) The fuel cell MEA according to (12), wherein a current collecting member is provided in contact with the outer surface of the hollow cylindrical MEA, and the current collecting member is made of a conductive wire. (Embodiment 8 of the invention) (14) The fuel cell MEA according to (12), wherein a current collecting member is provided in contact with the inner surface of the hollow cylindrical MEA, and the current collecting member is made of a conductive mesh. (Ninth Embodiment of the Present Invention) (15) A hollow cylindrical MEA is made into a cylindrical core material,
A catalyst-supporting substrate is provided on the outer periphery of the core material, then a catalyst layer is formed on the catalyst-supporting substrate by a sol-gel method, and then an electrolyte layer is integrally formed on the catalyst layer by a sol-gel method. The method for producing an MEA for a fuel cell according to claim 1, wherein the catalyst layer is integrally formed on the top by a sol-gel method, and then the core material is removed. (Embodiment 10 of the present invention)

In the fuel cell MEA production method (1) and the fuel cell MEA production method (2), a catalyst layer is produced by the sol-gel method, an electrolyte membrane is produced by the sol-gel method, and the electrolyte membrane and the catalyst layer are produced. Since and are integrally molded at the time of production by the sol-gel method, the catalyst layer and the electrolyte layer layer are not joined mechanically such as by hot pressing, but are integrated during the manufacturing process to reduce the electric resistance value of the joint, The output of the battery is improved. In the method (3) for producing a fuel cell catalyst layer, the catalyst layer can be produced by one sol-gel step of immersing the catalyst-supporting substrate in a sol-gel solution and pulling it up to gel. In the method for producing a catalyst layer for a fuel cell according to the above (4), since the sol-gel solution contains a water repellent substance as a component in addition to the proton conductive substance in advance, the catalyst layer is produced and the water repellent function is imparted in the same step. Can be done at. In the method for producing a catalyst layer for a fuel cell according to the above (5), the catalyst-supporting base material is surface-coated with the sol-gel solution to form a gel, and then immersed in a sol-gel solution containing a water-repellent substance as a component to form the outermost surface. Since the water-repellent layer is formed, only the water-repellent treatment can be made independent as a post-process, and the water-repellent treatment can be locally applied on only one surface of the catalyst layer. Above (3)
In the method for producing a catalyst layer for a fuel cell of to (5), the catalyst colloid is dispersed in the sol-gel solution. However, in the method for producing a catalyst layer for a fuel cell in (6) above, a catalyst-supporting group on which a catalyst is previously loaded is supported. The material is immersed in the sol-gel solution. The fuel cell catalyst layer may be manufactured by the method (6) for manufacturing a fuel cell catalyst layer. In the method (7) for producing a catalyst layer for a fuel cell, the catalyst-supporting base material is made of a carbon fiber sheet, so that the current collecting property is good. In the method for producing a catalyst layer for a fuel cell according to the above (8), carbon fibers are immersed in titania sol or titania + catalyst sol, and the surface is titania gel-coated or titania + catalyst gel-coated and baked in an ammonia gas or nitrogen atmosphere to form a surface. Since TiN or catalyst-containing TiN is formed, the current collecting property is improved and the energization resistance is reduced as compared with the case where only carbon fiber is used. In the method for producing a catalyst layer for a fuel cell according to (9) above, since the catalyst-supporting base material is a sheet in which Au wire is woven into a part of carbon fiber, the current collecting property is higher than that of carbon fiber alone. It becomes good and the conduction resistance is reduced. The fuel cell catalyst layer of (10) above is produced by any of the methods described in (3) to (9) above, and therefore has the actions and effects of (3) to (9) above. In the method for producing a fuel cell MEA according to (11) above, 3-glycidoxypropyltrimethoxysilane is added to a sol-gel solution when an electrolyte membrane is prepared, and an acrylic container is used as a gelling container. A thin electrolyte membrane can be manufactured. ME for fuel cell according to (12) above
In A, since the MEA is formed in a hollow cylindrical shape, the catalyst layer area can be increased as compared with the flat MEA, and the MEA and the fuel cell can be made compact. Above (1
In the fuel cell MEA of 3), a current collecting member is provided in contact with the outer surface of the hollow cylindrical MEA, and since the current collecting member is made of a conductive wire, there is variation in the outer diameter of the hollow cylindrical MEA. But the wire can contact the hollow cylindrical MEA,
High current collection performance can be obtained. ME for fuel cell according to the above (14)
In A, a current collecting member is provided in contact with the inner surface of the hollow cylindrical MEA, and since the current collecting member is made of a conductive mesh, high current collecting property can be obtained. In the method (15) for producing a fuel cell MEA, a hollow cylindrical MEA is made into a cylindrical core material, a catalyst-supporting substrate is provided on the outer periphery of the core material, and then a catalyst layer, an electrolyte layer, and a catalyst are provided. Since the layers are sequentially formed by the sol-gel method and then the core material is removed, a hollow cylindrical MEA having a low contact resistance can be manufactured without applying a pressure between the layers.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The fuel cell ME of the present invention is described below.
A, a method for producing the same, a catalyst layer for a fuel cell, and a method for producing the same will be described with reference to FIGS. The fuel cell 10 of the present invention is a solid polymer electrolyte fuel cell. The fuel cell 10 of the present invention is mounted in, for example, a fuel cell vehicle. However, it may be used for other than automobiles.

The solid polymer electrolyte fuel cell 10 has a membrane-electrode assembly (ME) as shown in FIG.
A: Membrane-Electrode Assembly 1) and a current collector 2 constitute a cell 3, a plurality of cells are laminated, and a terminal, an insulator, and an end plate are arranged at both ends in the cell lamination direction to form a stack. Is fastened and fixed by a fastening member extending outside the stack in the cell stacking direction. Membrane-electrode assembly 1
Is an electrode 13 (anode, fuel electrode) composed of an electrolyte membrane 11 composed of an ion exchange membrane and a catalyst layer 12 arranged on one surface of the electrolyte membrane, and an electrode (composed of a catalyst layer 12 arranged on the other surface of the electrolyte membrane). (Cathode, air electrode) 14. The cell 3 has fluid passages 15 and 16 for supplying fuel gas (anode gas, hydrogen) and oxidizing gas (cathode gas, oxygen, usually air) to the anode and cathode.
Are formed. The MEA 1 may have a flat plate shape, or may have a shape other than a flat plate, for example, a hollow cylinder shape. The current collector 2 may have a flat plate shape, or may have a shape other than a flat plate, such as a wire shape or a mesh shape.

In the method of manufacturing the MEA 1 for a fuel cell of the present invention, the catalyst layer 12 is manufactured by the sol-gel method, the electrolyte membrane 11 is manufactured by the sol-gel method, and the electrolyte membrane 11 and the catalyst layer 12 are integrally formed at the time of manufacturing by the sol-gel method. Is molded into. MEA for a fuel cell of the present invention produced by the method
Reference numeral 1 denotes a catalyst layer 12 produced by the sol-gel method, and an electrolyte layer (electrolyte membrane) 11 produced by the sol-gel method.
And the catalyst layer 12 and the electrolyte layer 11 are integrally formed at the time of production by the sol-gel method. In the sol-gel method,
As shown in FIG. 2, hydrolysis of a gel skeleton component (metal alkoxide such as tetraethoxysilane (TEOS), 3-glycidoxypropyltrimethoxysilane (GPTS), etc.) in a sol solution (solvent is alcohol, etc.), The sol is gelated by repeating dehydration polycondensation, and the obtained gel is dried. The sol solution contains TEO as a gel skeleton component.
An example of the component when S is used is TEOS: EtOH (ethanol): H ₂ O: HCl =
It is 1: 4: 4: 0.01 (molar ratio), and an example of the component when GPTS is used as the gel skeleton component is: GPTS: EtOH (ethanol): H ₂ O: HCl =
It is 1: 4: 4: 0.01 (molar ratio).

In the method for producing the fuel cell MEA and the fuel cell MEA, the catalyst layer 1 is formed by the sol-gel method.
2 is produced, the electrolyte membrane 11 is produced by the sol-gel method, and the electrolyte membrane 11 and the catalyst layer 12 are integrally molded at the time of production by the sol-gel method. Therefore, the catalyst layer 12 and the electrolyte layer layer 1
The joining with No. 1 is not mechanical joining such as hot pressing, but is integrated in the manufacturing process, the electric resistance value of the joining portion is reduced, and the output of the fuel cell is improved.

Next, each embodiment of the present invention will be described. [First Embodiment of the Invention] A first embodiment of the present invention relates to a method for producing a catalyst layer 12, a catalyst layer 12 produced by the production method, and a method for producing an MEA 1 using the catalyst layer 12. is there. As shown in FIG. 1, the method of manufacturing the catalyst layer 12 includes a solvent (eg, a catalyst (eg, Pt, Ru, etc.) containing a proton conductive material (eg, tungstophosphoric acid, silicotungstic acid, etc.) as a component.
Etc.) A catalyst-supporting base material 21 (for example, a carbon fiber sheet 21) is dipped in a sol-gel solution 20 in which a colloid is dispersed and pulled up, and the catalyst-supporting base material 21 is surface-coated with the sol-gel solution 20 and dried and heated (for example, , 60-70 ° C x 3
(0 to 60 minutes) A method of gelling. The catalyst layer 12 is obtained by this method. The method for producing the MEA 1 using the catalyst layer 12 is a well-known method in which an electrolyte membrane 11 of a proton conductive material is produced by a sol-gel method in which phosphoric acid or the like is added. This is a method of integrally molding carbon fibers having Pt supported on the surface thereof by the sol-gel method to obtain MEA1. By immersing the carbon fiber sheet 21 in the sol-gel solution 20 and pulling it up, a few n
A coat film having a thickness of m to several μm is formed. Pt in the coat film makes efficient contact with the carbon fibers and exhibits the function of the catalyst layer 12. In this form, the carbon fibers also act as a current collector.

Further, the sol-gel solution 20 may contain a water repellent substance (for example, fluoroalkylsilane (FAS)) as a component in addition to the proton conductive substance. An example of the composition when FAS is added is FAS: 1.6 g,
TEOS: 5.12 g, EtOH: 48.75 g,
0.05N HCl: 6.32 g. In that case,
In the formed coat film, FAS acts as a water repellent component, so that even when used in the oxygen electrode of a fuel cell, the water generated by the reaction does not stay and the catalyst layer 12 functions efficiently without causing flooding. To do.

Regarding the operation of the first embodiment of the present invention,
The catalyst layer 12 is formed by one sol-gel step of immersing the catalyst-supporting base material 21 in the sol-gel solution 20 and pulling it up for gelation.
Can be produced. Further, since the sol-gel solution 20 contains a water-repellent substance as a component in advance in addition to the proton conductive substance, the catalyst layer 12 can be produced and the water-repellent function can be imparted in the same step.

[Embodiment 2 of the Invention] Embodiment 2 of the present invention is the same as Embodiment 1 of the invention, except that the water repellent treatment (F
AS and the like) as a post-treatment and a catalyst layer produced by the method. That is, the method for producing a catalyst layer for a fuel cell according to Embodiment 2 of the present invention is to support a catalyst in a sol-gel solution 20 in which a catalyst colloid is dispersed in a solvent containing a proton conductive substance as a component and not containing a water repellent substance. The substrate 21 is dipped and pulled up, and the catalyst-supporting substrate is surface-coated with a sol-gel solution for gelation, and then dipped in a sol-gel solution containing a water-repellent substance (for example, FAS) as a component to form the outermost surface of the surface coat. The method comprises forming a water repellent layer. Although the second embodiment of the present invention is used for producing an oxygen electrode, the step of forming a water repellent layer is not performed on a hydrogen electrode that does not require water repellency. That is,
In the first embodiment of the present invention, in the oxygen electrode, since the water-repellent component becomes an impurity with respect to the original function of the catalyst layer, the water-repellent function is given only to the minimum necessary outermost surface. This method can also be applied to the case where it is desired to change the catalyst component or structure in the thickness direction of the catalyst layer. For example, a catalyst-supporting base material is surface-coated with a sol-gel solution to gel, and then the second side and the third sol solution having different Pt contents are sequentially dipped to gel the membrane side. The catalyst layer and the collector side can also function as a diffusion layer. Further, for example, when it is desired to form the water-repellent film only on one surface (electrolyte membrane side), the sixth embodiment of the invention described below may be applied.

Regarding the operation of the method for producing a catalyst layer for a fuel cell according to Embodiment 2 of the present invention, the catalyst-supporting base material 21 is surface-coated with a sol-gel solution to form a gel, and then a water-repellent substance is contained as a component. Since the water-repellent layer is formed on the outermost surface by immersing it in the sol-gel solution described above, only the water-repellent treatment can be made independent as a post-process, and the water-repellent treatment can be locally applied such as only one surface of the catalyst layer 12. .

[Embodiment 3 of the present invention] In Embodiment 3 of the present invention, the conductivity (collection characteristics) of the carbon fiber sheet which is the catalyst supporting base material used in Embodiments 1 and 2 of the present invention And a catalyst layer for a fuel cell produced by the method. In the method for producing a catalyst layer for a fuel cell according to Embodiment 3 of the present invention, the catalyst-supporting base material 21 is prepared by immersing carbon fiber in titania (TiO ₂ ) sol or (titania + catalyst) sol and titania gel coating or (Titania + catalyst)
The gel-coated product is fired in an atmosphere of ammonia gas or nitrogen to form a fiber sheet having TiN or catalyst-containing TiN formed on the surface.

Regarding the operation of the method for producing a catalyst layer for a fuel cell according to the third embodiment of the present invention, the carbon fiber is dipped in titania sol or titania + catalyst sol and the surface is titania gel-coated or titania + catalyst gel-coated and ammonia gas is used. Alternatively, since TiN or catalyst-containing TiN is formed on the surface by firing in a nitrogen atmosphere, the current collecting property becomes 2-3 times better than the case of using only carbon fiber, and the energization resistance also decreases. The specific resistance is C: 4 to 7E-5 Ωcm, Ti
N: 2.2E-5 Ωcm, TiC: 18.0E-5 Ωc
m.

[Embodiment 4 of the present invention] In Embodiment 4 of the present invention, the conductivity (collection characteristic) of the carbon fiber sheet which is the catalyst supporting base material used in Embodiments 1 and 2 of the present invention And a catalyst layer for a fuel cell produced by the method. In the method for manufacturing a catalyst layer for a fuel cell according to Embodiment 4 of the present invention, the catalyst-supporting base material 21 has a portion of carbon fiber A
It consists of a sheet woven with u-line. The ratio of Au wire to be woven is one for every 10 to 1,000 carbon fibers. Regarding the operation of the fourth embodiment of the present invention, since the catalyst supporting base material 21 is made of a sheet in which Au wire is woven into a part of carbon fiber, the current collecting property is better than that in the case of only carbon fiber. Therefore, the conduction resistance is also reduced. The specific resistance of Au is 2.4E-6 Ωcm.

[Fifth Embodiment of the Present Invention] A fifth embodiment of the present invention is an MEA 1 in which the catalyst layer and the electrolyte membrane 11 (proton conductive membrane) of the first to fourth embodiments of the present invention are integrally formed, and the MEA 1 thereof. The present invention relates to a manufacturing method. As a method of integration, there is a method of laminating (one layer on the other layer) and gelling, and a method of adhering the electrolyte membrane 11 and the gel-filled carbon fiber with a sol-gel material.

Method of Laminating and Gelling (FIG. 1) It is manufactured by the following steps. (1) Carbon fibers carrying Pt, Ru (other catalysts if necessary), etc. are immersed in a proton conductive sol-gel solution and pulled up to form a sol to form the catalyst layer 12 (see FIG. 1). (Part (1)) (2) Proton-conducting gel is formed all at once or laminated on the gel material on one surface of the catalyst layer obtained in step (1) to form the electrolyte membrane 11. (3) In the gel material on the other surface of the catalyst layer obtained in step (1),
In the same manner as in step (1), the carbon fiber with a catalyst immersed in the sol-gel solution is applied to the electrolyte membrane 11 in the step (2) before the sol-gel solution attached to the surface of the carbon fiber with a catalyst is completely gelled. Overlap and integrate with the gel materials up to (2). Instead of the above (1), the catalyst layers 12 of Embodiments 1 to 4 of the present invention may be used. The difference is that in the catalyst layers 12 of Embodiments 1 to 4 of the present invention, the catalyst is colloidally dispersed in the sol-gel solution.
In the step (1) of 5 of the embodiment of the present invention, the carbon fiber is preliminarily loaded with the catalyst.

The method described above and the ME manufactured by the method
The action of A is as follows. Conventionally, a catalyst layer is pressure-bonded to an electrolyte membrane while applying heat with a hot press or the like, and the separator (carbon plate or the like) collects electricity through a current collecting band (diffusion layer) such as a carbon fiber sheet. On the other hand, in the present invention, the portion corresponding to the electrolyte membrane 11, the catalyst layer, and the portion corresponding to the current collecting band are integrally manufactured by applying the sol-gel method. As a result, if the carbon fiber itself has two functions of a catalyst layer and a current collecting band and the current is collected directly from the carbon fiber, the current will not be collected from the separator as in the conventional case. Contact resistance is gone,
A cell structure with significantly reduced resistance can be provided.

Method of adhering the electrolyte membrane 11 and the carbon fiber filled with gel with a sol-gel material In this method, the electrolyte membrane 11 is prepared in advance by a sol-gel method, and the electrolyte membrane 11 is immersed in a sol-gel solution and coated with the sol-gel solution. The catalyst layer 12 made of carbon fiber is adhered to both surfaces of the electrolyte membrane 11 before the gel of the electrolyte membrane 11 and the catalyst layer 12 is completely solidified. That is, the treatment according to the above step (3) is performed on both surfaces of the electrolyte membrane 11. If the gels are put together in a wet state before they solidify, they will be bonded together with the gel material. The action of the above method is similar to that of the above method.

[Sixth Embodiment of the Present Invention] A sixth embodiment of the present invention is a thin film and has a large area (for example, 15 cm × 1).
The present invention relates to a method for producing the electrolyte membrane 11 (proton conductive membrane) of about 5 cm or more) by the sol-gel method. When tetraethoxysilane (TEOS) is used as a gel skeleton component in the sol-gel method: -Shrinkage occurs in the drying process and cracks occur. -If a rapid heat treatment is performed, the solvent volatilizes and cracks occur.・ It is difficult to produce flat thin films. As a result, it is difficult to produce a thin and large-area electrolyte membrane 11 (proton conductive membrane) by the sol-gel method. In order to solve this, in the method for producing the fuel cell MEA according to the sixth embodiment of the present invention, when the electrolyte membrane 11 is produced, 3-glycidoxypropyltrimethoxysilane is used as a gelling skeleton component in the sol-gel solution. Is added, and an acrylic container is used as a gelling container.

In the gel preparation using GPTS as a raw material, as shown in the following formula: OCH ₃ is hydrolyzed by water under an acid or base catalyst, and the epoxy ring is opened at low pH. -Since it has an organic chain in the molecule and this is incorporated into the gel skeleton, flexibility can be imparted to the gel layer.・ No cracking occurs because it does not shrink when dried. Shows the properties such as. The composition example of the sol-gel liquid is as follows. GPTS: EtOH: H ₂ O: HCl = 1: 4: 4:
0.01 (molar ratio)

[0024]

[Chemical 1]

Regarding the operation of the sixth embodiment of the present invention,
The addition of GPTS makes it difficult for lateral shrinkage to occur during gelation (condensation and drying), and thus does not cause cracking or cracking of the film. Also, if the selection of the container is bad, the thin film gelated may be damaged when adsorbed to the container and peeled off, but it was found that the use of an acrylic container facilitates the separation of the thin film from the container, The container was an acrylic container. The addition of GPTS and the use of acrylic containers allows the formation of large area thin films.

As an application of the large area thin film forming method of the sixth embodiment of the present invention, the following method can be used when it is desired to form a gel on only one surface of a carbon fiber sheet. As shown in FIG. 3, put the carbon fiber sheet on the acrylic plate,
The sol-gel solution is poured from the upper side of the tilt, and the whole surface is kept wet. Depending on the case, the sol-gel liquid may be sprayed from the upper surface of the carbon fiber. Further, the carbon fiber sheet 21 immersed in the sol-gel solution is placed on the acrylic plate 30,
The acrylic plate 30 may be tilted. By drying the gel with the acrylic plate tilted, it is possible to obtain a catalyst layer having a gel film (for example, an electrolyte film) only on the acrylic plate 30 side. The gel film thickness can be controlled (changed) by the inclination angle of the acrylic plate 30.

[Embodiment 7 of the Invention] As shown in FIGS. 4 and 5, Embodiment 7 of the present invention increases the degree of freedom in shape and allows not only flat plates but shapes other than flat plates (for example, ME for fuel cell, which may have a hollow cylindrical shape, that is, a pipe shape
Regarding A1. The sol-gel method may or may not be applied to the production of this MEA. MEA
By making 1 into a pipe shape, the gas-liquid reaction interface (catalyst layer area) is about 3 to 7 times that of a flat plate MEA per unit volume.
It is possible to obtain an MEA having This makes it possible to achieve 1/7 to 1/3 compactness with the same performance. Moreover, if the conductive film production by the sol-gel method is applied,
The MEA can be manufactured by an easy process.

A hollow cylindrical shape having a catalyst layer (and a current collecting carbon fiber) provided on the inner surface and the outer surface, for example, a diameter of 1 mm.
It is possible to adopt a structure in which the electrolyte pipes are arranged and current is collected from the inner surface and the outer surface of each pipe. For collecting current from the outer surface of the pipe, the current collector 2 composed of a current collector plate is pipe-shaped M
The current can be collected by contacting the outer surface of the EA and by collecting the current from the inner surface of the pipe by bringing the current collector 2 composed of a current collector into contact with the inner surface of the pipe-shaped MEA. By flowing hydrogen through the fluid passage 15 inside the pipe and flowing oxygen (air) through the fluid passage 16 formed by the gap between the outer periphery of the pipe and the outer current collector plate, the anode and cathode reactions can be performed on the inner and outer surfaces of the pipe, respectively. The fuel cell 10 is obtained by raising.

A comparison of the catalyst layer areas of the pipe-shaped MEA and the flat plate-shaped MEA is as follows. In the plate-shaped unit cell, MEA having an area of 20 cm × 20 cm is used, and both sides thereof are sandwiched by separators. Assuming that this is a single cell, its thickness is 6.2 mm when a carbon separator is used, and it is 3. when a metal separator is used.
It is 4 mm. The catalyst layers of the anode and the cathode therein are 400 cm ² each. On the other hand, when the pipe MEA according to the seventh embodiment of the present invention is used, the pipe MEA
When the outer diameter of the pipe MEA is set to 1 mm, for example, the outer surface area of one pipe MEA is 6.2 when the pipe MEA is arranged in the length and width of 20 cm.
8 cm ² (= 0.1 × π × 20), which is 200
1.5mm thickness (pipe diameter 1
mm + outer current collector plate thickness 0.5 mm), a catalyst layer area of 1256 cm ² can be formed. Therefore, the same capacity (for example, when using a carbon separator, 248 cm ³
= 20 cm × 20 cm × 6.2 mm), the flat MEA has a total catalyst area of 400 cm ² , whereas the pipe MEA according to the seventh embodiment of the present invention has 5196 cm ^2. It is possible to obtain about 13 times the area. Compared with the flat plate MEA of the metal separator (136 cm ³ = 20 cm × 20 cm × 3.4)
mm), the total area of the catalyst is 28 in the case of the pipe MEA of the present invention.
It becomes 48 cm ² , and a catalyst area of about 7 times can be obtained. Conversely, if the same area is acceptable, the pipe ME of the present invention
The volume of A will be 1/13 of the flat MEA,
It can be said to be an epoch-making method. Pipe M of Embodiment 7 of the present invention
The EA is arranged in a line in the cell stacking direction. The reason is that if there are multiple rows (for example, 3 rows) in the cell stacking direction.
In that case, the air (oxygen) is not successfully supplied to the gaps between the pipes in the center (the gap between the first row and the second row, and the gap between the second row and the third row).

[Eighth Embodiment of the Present Invention] As shown in FIGS. 6 and 7, the eighth embodiment of the present invention is a hollow cylindrical MEA.
1. A current collecting member (current collector) 2 is provided in contact with the outer surface of the fuel cell 1. The current collecting member 2 is a fuel cell M made of a conductive wire.
Regarding EA. In the eighth embodiment of the present invention, a conductive wire (current collecting wire) 2 is used instead of the current collecting plate 2 on the outside of the pipe MEA shown in the seventh embodiment of the invention.
It is a fuel cell structure that collects current by knitting A1. By collecting the current using the conductive wire 2, it is possible to reliably collect the current. Even if the thickness of each pipe MEA 1 varies, there is a possibility that there is a pipe MEA that does not come into contact with the plate, but the wire 2 can surely come into contact and collect current, so that no current collection loss occurs, High current collection performance can be obtained. The areas of the current collecting layers are compared as follows. When the diameter of the current collecting wire 2 is 0.5 mm, a portion occupied by the current collecting wire also occurs in the direction in which the pipes MEA 1 are arranged, so that the number of arranged pipes MEA becomes 1 / 1.5, and thus the obtained catalyst is obtained. Although the surface area of the layer becomes 1 / 1.5, the area is 6.5 times that of the carbon separator and 3.5 times that of the metal separator.

[Ninth Embodiment of the Present Invention] In a ninth embodiment of the present invention, a current collecting member (current collector) 2 is provided in contact with the inner surface of the hollow cylindrical MEA 1, and the current collecting member 2 is provided. Relates to a fuel cell MEA made of a conductive mesh. In the structure shown in the seventh embodiment of the present invention, the pipe M
Gold coated SUS instead of the current collector inside EA1
Use a mesh or a cylindrical gold wire mesh. In the manufacturing method, carbon fibers (collection band) are wound around this mesh to form a catalyst layer and an electrolyte membrane according to the fifth embodiment of the present invention. According to the method of the fifth embodiment of the present invention, an integrated structure can be manufactured without the need for pressurization,
There is no need to pressurize the mesh and MEA contact,
High current collection performance can be obtained.

[Embodiment 10 of the present invention] Embodiment 10 of the present invention relates to a method of manufacturing a hollow cylindrical MEA 1. In the tenth embodiment of the present invention, a cylindrical core material (solid cylinder having an outer diameter of about 0.4 mm) is made of a low melting point brazing material (paraffin or the like), and Lillian knitting or A catalyst supporting substrate (for example, carbon fiber) is knitted by sock knitting or the like. Then, a catalyst layer is formed on the catalyst-supporting substrate (knitted carbon fiber) by the sol-gel method (the method of the fifth embodiment of the present invention), and then an electrolyte layer is integrally formed on the catalyst layer by the sol-gel method. A catalyst layer is integrally formed on the electrolyte layer by a sol-gel method. After that, the hollow cylindrical ME is removed by removing the core material (removing by melting, etc.).
A is produced. The catalyst layer current collecting portion on the outer periphery may also be subjected to the same sol-gel method treatment after weaving carbon fibers in the same manner as above after forming the electrolyte. If it is difficult to knit the carbon fiber on the outer peripheral side after forming the core material and electrolyte, the knitting method (sock knitting, etc.) that spreads in the concentric direction is used in advance from the target (core material diameter, diameter after electrolyte formation). It suffices to knit in a slightly smaller diameter, pass through the core material while unfolding, and apply the treatment of the fifth embodiment of the present invention to this. Regarding the operation of Embodiment 10 of the present invention, the hollow cylindrical MEA is
Since a cylindrical core material is prepared, a catalyst-supporting base material is provided on the outer periphery of the core material, then a catalyst layer, an electrolyte layer, and a catalyst layer are sequentially formed by a sol-gel method, and then the core material is removed. The hollow cylindrical MEA 1 having a low contact resistance can be manufactured without applying pressure between the layers.

[0033]

According to the method for producing an MEA for a fuel cell according to claim 1 and the MEA for a fuel cell according to claim 2, a catalyst layer is produced by a sol-gel method, an electrolyte membrane is produced by a sol-gel method, and an electrolyte membrane is formed. Since the catalyst layer and the catalyst layer are integrally molded during the production by the sol-gel method, the catalyst layer and the electrolyte layer layer are not joined mechanically such as by hot pressing, but are integrated during the manufacturing process, and the electrical resistance value of the joint is reduced. The output of the fuel cell is improved. According to the method for producing a catalyst layer for a fuel cell of claim 3, the catalyst layer can be produced by one sol-gel step of immersing the catalyst-supporting substrate in a sol-gel solution and pulling it up to gel. According to the method for producing a catalyst layer for a fuel cell of claim 4, since the water-repellent substance is contained as a component in advance in the sol-gel solution in addition to the proton conductive substance, the preparation of the catalyst layer and the imparting of the water-repellent function are performed in the same manner. It can be done in process. According to the method for producing a catalyst layer for a fuel cell of claim 5, the catalyst-supporting base material is surface-coated with the sol-gel solution to be gelated, and then dipped in a sol-gel solution containing a water-repellent substance as a component for the outermost surface. Since the water-repellent layer is formed on, the water-repellent treatment can be independently performed as a post-process, and the water-repellent treatment can be locally applied on only one surface of the catalyst layer. According to the method for producing a catalyst layer for a fuel cell according to claims 3 to 5, the catalyst colloid is dispersed in the sol-gel solution. However, according to the method for producing a catalyst layer for a fuel cell according to claim 6, the catalyst is previously loaded. The catalyst supporting substrate is immersed in the sol-gel solution. The fuel cell catalyst layer may be manufactured by the method for manufacturing a fuel cell catalyst layer according to claim 6. According to the method for producing a catalyst layer for a fuel cell of claim 7, the catalyst supporting base material is made of a carbon fiber sheet, so that the current collecting property is good. According to the method for producing a catalyst layer for a fuel cell of claim 8, the surface is obtained by immersing carbon fiber in titania sol or titania + catalyst sol and coating the surface with titania gel coat or titania + catalyst gel coat in an ammonia gas or nitrogen atmosphere. Since TiN or catalyst-containing TiN is formed on the substrate, the current collecting property is improved and the energization resistance is reduced as compared with the case where only carbon fiber is used. According to the method for producing a catalyst layer for a fuel cell of claim 9, since the catalyst-supporting base material is a sheet in which Au wire is woven into a part of carbon fiber, the current collecting property is higher than that in the case of using only carbon fiber. Is improved and conduction resistance is reduced. Claim 1
The fuel cell catalyst layer of No. 0 is produced by the method according to any one of claims 3 to 9, and therefore has the actions and effects obtained in claims 3 to 9. According to the method for producing a fuel cell MEA of claim 11, 3-glycidoxypropyltrimethoxysilane is added to a sol-gel solution when an electrolyte membrane is produced, and an acrylic container is used as a gelling container.
A large area thin film electrolyte membrane can be manufactured. According to the MEA for a fuel cell of the twelfth aspect, since the MEA is formed in a hollow cylindrical shape, the area of the catalyst layer can be increased as compared with the flat MEA, and the MEA and the fuel cell can be made compact. According to the fuel cell MEA of claim 13, the current collecting member is provided in contact with the outer surface of the hollow cylindrical MEA,
Since the current collecting member is made of a conductive wire, it has a hollow cylindrical shape M.
Even if the outer diameter of EA varies, the wire has a hollow cylindrical shape M
It can come into contact with EA and obtains high current collection. According to the MEA for a fuel cell of claim 14, the current collecting member is provided in contact with the inner surface of the hollow cylindrical MEA, and the current collecting member is made of a conductive mesh, so that high current collecting property is obtained. According to the method for producing an MEA for a fuel cell of claim 15, a hollow cylindrical MEA is made into a cylindrical core material, a catalyst supporting base material is provided on the outer periphery of the core material, and then a catalyst layer, an electrolyte layer, Since the catalyst layers are sequentially formed by the sol-gel method and then the core material is removed, the hollow cylindrical MEA having a low contact resistance can be manufactured without applying a pressing force between the layers.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a method of manufacturing a fuel cell MEA including a method of manufacturing a fuel cell catalyst layer of the present invention in the order of steps.

FIG. 2 is a cross-sectional view showing a sol-gel method used in a method for producing a fuel cell MEA including a method for producing a fuel cell catalyst layer of the present invention in the order of steps (sol-gel solution, gelation).

FIG. 3 is a cross-sectional view of an acrylic container and gelation according to a sixth embodiment of the present invention.

FIG. 4 is a sectional view of a pipe MEA according to a seventh embodiment of the present invention.

FIG. 5 is a plan view of a pipe MEA according to a seventh embodiment of the present invention.

FIG. 6 is a sectional view of a pipe MEA and a collecting wire according to an eighth embodiment of the present invention.

FIG. 7 is a side view of FIG.

[Explanation of symbols]

1 MEA 2 Current collector (current collector, collector wire, collector mesh) 3 cells 10 (Polymer electrolyte type) fuel cell 11 Electrolyte membrane 12 Catalyst layer 13, 14 electrodes 15, 16 fluid flow path 20 Sol-gel solution 21 Catalyst-supporting substrate (for example, carbon fiber sheet) 30 acrylic container (acrylic plate)

Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01M 8/02 H01M 8/02 P // H01M 8/10 8/10 F term (reference) 5H018 AA06 AS01 BB00 BB01 BB05 BB08 CC03 CC06 DD05 DD08 EE03 EE05 EE11 5H026 AA06 BB01 BB03 BB04 BB08 BB10 CC06 CV02 CX02 CX04 CX06 EE02 EE05 EE11

Claims (15)

[Claims] 1. A method for producing an MEA for a fuel cell, wherein a catalyst layer is produced by a sol-gel method, an electrolyte membrane is produced by a sol-gel method, and the electrolyte membrane and the catalyst layer are integrally formed during production by the sol-gel method. 2. A catalyst layer produced by the sol-gel method, and an electrolyte layer produced by the sol-gel method,
An MEA for a fuel cell, wherein the catalyst layer and the electrolyte layer are integrally formed during production by a sol-gel method. 3. The catalyst-supporting substrate is surface-coated with the sol-gel solution and gelled by immersing the catalyst-supporting substrate in a sol-gel solution in which a catalyst colloid is dispersed in a solvent containing a proton conductive substance as a component. A method for producing a catalyst layer for a fuel cell. 4. The catalyst layer for a fuel cell according to claim 3, wherein the sol-gel solution contains a water repellent substance as a component in advance in addition to the proton conductive substance. 5. A catalyst-supporting substrate is dipped in a sol-gel solution in which a catalyst colloid is dispersed in a solvent containing a proton-conducting substance as a component and not containing a water-repellent substance, and the catalyst-supporting substrate is formed by the sol-gel solution. A method for producing a catalyst layer for a fuel cell, which comprises surface-coating and gelling, and then immersing in a sol-gel solution containing a water-repellent substance as a component to form a water-repellent layer on the outermost surface. 6. A gel for which a catalyst-supporting substrate carrying a catalyst in advance is immersed in a sol-gel solution containing a proton conductive substance as a component, and the catalyst-supporting substrate carrying the catalyst is surface-coated with the sol-gel solution. Of producing a catalyst layer for a fuel cell, which is made into a polymer. 7. The method for producing a catalyst layer for a fuel cell according to claim 3, 4, 5 or 6, wherein the catalyst supporting base material is a carbon fiber sheet. 8. The catalyst-supporting base material is obtained by immersing carbon fiber in titania sol or titania + catalyst sol and coating the surface with titania gel coat or titania + catalyst gel calcination in an atmosphere of ammonia gas or nitrogen to form TiN or 7. The method for producing a catalyst layer for a fuel cell according to claim 3, claim 4, claim 5, or claim 6, which comprises a fiber sheet on which catalyst-containing TiN is formed. 9. The catalyst layer for a fuel cell according to claim 3, wherein the catalyst-supporting base material is a sheet in which Au wire is woven into a part of carbon fiber. Production method. 10. A fuel cell catalyst layer produced by the method according to claim 3. 11. The method for producing an electrolyte membrane, wherein 3-glycidoxypropyltrimethoxysilane is added to a sol-gel solution, and an acrylic container is used as a gelling container.
A method for producing the MEA for a fuel cell described. 12. The fuel cell MEA according to claim 2, wherein the MEA is formed in a hollow cylindrical shape. 13. The fuel cell MEA according to claim 12, wherein a current collecting member is provided in contact with the outer surface of the hollow cylindrical MEA, and the current collecting member is made of a conductive wire. 14. The fuel cell MEA according to claim 12, wherein a current collecting member is provided in contact with the inner surface of the hollow cylindrical MEA, and the current collecting member is made of a conductive mesh. 15. A hollow cylindrical MEA is made into a cylindrical core material, a catalyst-supporting base material is provided on the outer periphery of the core material, and then a catalyst layer is formed on the catalyst-supporting base material by a sol-gel method. The fuel cell according to claim 1, wherein the electrolyte layer is integrally formed on the catalyst layer by the sol-gel method, the catalyst layer is integrally formed on the electrolyte layer by the sol-gel method, and then the core material is removed. Method of manufacturing MEA.