JP2010251033A - Method of manufacturing membrane-catalyst assembly, membrane-catalyst assembly, and fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress degradation of characteristics of a fuel cell while reducing a used amount of catalyst ink. <P>SOLUTION: In the method of manufacturing a membrane-catalyst assembly 110 having an electrolyte membrane of a predetermined thickness and catalyst layers CL formed on both surfaces of the electrolyte membrane, the catalyst layer CL is formed by coating the catalyst ink on one surface of the first electrolyte membrane HM formed on a carrier film CF and having a smaller thickness than a predetermined thickness. The catalyst layer CL is formed by coating the catalyst ink on one surface of the second electrolyte membrane HM having a thickness obtained by subtracting the thickness of the first electrolyte membrane HM from the predetermined thickness, then the first electrolyte membrane HM and second electrolyte membrane HM are bonded to each other. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for producing a membrane / catalyst assembly constituting a fuel cell.

  As a fuel cell, a fuel cell having an electrolyte membrane and a catalyst layer formed on both surfaces of the electrolyte membrane is used. As a method for producing such a fuel cell, a method is provided in which a catalyst layer is formed on a porous layer formed on a gas diffusion layer for adjusting the moisture of the electrolyte membrane, and a member on which the catalyst layer is formed is joined to the electrolyte membrane. It has been known. In this manufacturing method, in order to form a catalyst layer in the porous layer, a catalyst ink that is a raw material of the catalyst layer is applied to the porous layer. When the catalyst ink is applied to the porous layer, the applied catalyst ink penetrates into the porous layer, and the amount of the catalyst ink for forming the catalyst layer increases. Therefore, as a method for manufacturing a fuel cell in which a catalyst layer is not applied on a porous layer, a catalyst layer is formed on a film, and the formed catalyst layer is transferred to an electrolyte membrane to form catalyst layers on both sides of the electrolyte membrane. Decal methods have been proposed. According to this decurling method, since the catalyst ink is applied onto the film, the catalyst layer can be formed with a smaller amount of the catalyst ink.

JP 2004-146076 A JP 2007-141684 A

  However, in the membrane / catalyst assembly formed using the decal method, when the catalyst ink is dried, the electrolyte material contained in the catalyst ink may be unevenly distributed on the film side. When such uneven distribution of the electrolyte material occurs, diffusion of the gas supplied to the fuel cell in the catalyst layer may be hindered, and the characteristics of the fuel cell may be deteriorated.

  The present invention has been made in order to solve the above-described conventional problems, and an object of the present invention is to suppress deterioration in characteristics of a fuel cell while reducing the amount of catalyst ink used.

  In order to solve at least a part of the above problems, the present invention can be realized as the following forms or application examples.

[Application Example 1]
A method of manufacturing a membrane / catalyst assembly having an electrolyte membrane having a predetermined thickness and a catalyst layer formed on both surfaces of the electrolyte membrane, wherein one surface of the first electrolyte membrane is thinner than the predetermined thickness And forming the catalyst layer on one surface of a second electrolyte membrane having a thickness obtained by subtracting the thickness of the first electrolyte membrane from the predetermined thickness. A method for producing a membrane / catalyst assembly in which the electrolyte membrane is joined to the second electrolyte membrane.

  In this application example, the catalyst layer is formed by applying catalyst ink to the electrolyte membrane. Since the catalyst ink does not penetrate into the electrolyte membrane, the catalyst layer can be formed with a smaller amount of the catalyst ink. Even when the electrolyte material is unevenly distributed when the catalyst ink is dried, the electrolyte material is unevenly distributed on the electrolyte membrane side, so that the gas diffusibility in the catalyst layer is maintained, and the characteristics of the fuel cell are deteriorated. It is suppressed.

[Application Example 2]
The method for producing a membrane / catalyst assembly according to Application Example 1, wherein each of the first and second electrolyte membranes is formed on a substrate, and the catalyst layer is opposite to the substrate. A method for producing a membrane / catalyst assembly formed by applying the catalyst ink to a side surface.

  In this application example, the catalyst ink is applied to the surface of the electrolyte membrane formed on the substrate opposite to the substrate. Therefore, since the electrolyte membrane can be supported by the base material when the catalyst ink is applied, the swelling and shrinkage of the electrolyte membrane due to the catalyst ink can be suppressed, and the formation of the catalyst layer by applying the catalyst ink becomes easier. .

[Application Example 3]
The method for producing a membrane / catalyst assembly according to Application Example 2, wherein the substrate has flexibility.

  When the base material has flexibility, the base material on which the electrolyte membrane is formed and the base material on which the electrolyte membrane and the catalyst layer are formed can be wound on a roll. Therefore, the mass productivity of the electrolyte membrane in which the catalyst layer is formed can be further increased by using the roll-to-roll method.

[Application Example 4]
4. The method of manufacturing a membrane / catalyst assembly according to any one of application examples 1 to 3, wherein the thickness of the first and second electrolyte membranes is ½ of the predetermined thickness.

  By setting the thickness of the first and second electrolyte membranes to ½ of the predetermined thickness, the catalyst layers can be formed on the first and second electrolyte membranes in the same process. Therefore, the mass productivity of the membrane / catalyst assembly can be further increased.

[Application Example 5]
5. The method for producing a membrane / catalyst assembly according to any one of Application Examples 1 to 4, further comprising providing a protective film on an outer edge of the catalyst layer of the membrane / catalyst assembly.

  By providing a protective film on the outer edge of the catalyst layer, the strength of the membrane / catalyst assembly can be increased.

  The present invention can be realized in various modes. For example, a method for manufacturing a membrane / catalyst assembly, a membrane / catalyst assembly manufactured using the manufacturing method, and the membrane / catalyst assembly It can implement | achieve in aspects, such as a fuel cell and fuel cell system which have these, and a vehicle etc. which have those fuel cells and fuel cell system.

The cross-sectional schematic diagram which shows the structure of the fuel cell to which this invention is applied. Process drawing which shows the manufacturing process of a membrane and catalyst assembly. Explanatory drawing which shows the structure of the catalyst layer coating apparatus for forming a catalyst layer on a semi-thick electrolyte membrane. Process drawing which shows the manufacturing process of a membrane electrode assembly. Process drawing which shows the comparative example of the manufacturing process of a membrane electrode assembly. Process drawing which shows the comparative example of the manufacturing process of a membrane and catalyst assembly. The cross-sectional schematic diagram which shows the film | membrane and catalyst assembly of 2nd Example.

A. First embodiment:
A1. Fuel cell configuration:
FIG. 1 is a schematic cross-sectional view showing the configuration of a fuel cell 100 to which the present invention is applied. The fuel cell 100 has a configuration in which a membrane electrode assembly (MEA) 120 is sandwiched between separators 130 and 140. The membrane / electrode assembly 120 includes a porous membrane 122, 124 and gas diffusion on both sides of a membrane-catalyst assembly (CCM) 110 in which catalyst layers 114, 116 are formed on both sides of the electrolyte membrane 112. It is formed by being sandwiched between layers 126 and 128. In addition, as a fuel cell, it can also be set as the structure which laminated | stacked multiple fuel cells 100 shown in FIG.

  The electrolyte membrane 112 is a proton conductive ion exchange membrane made of a fluorine resin material such as Nafion (trademark of DuPont) and having good conductivity in a wet state. The catalyst layers 114 and 116 include an electrolyte material and carrier particles supporting the catalyst. The catalyst layers 114 and 116 of the first embodiment include carbon particles carrying a platinum catalyst and an electrolyte (Nafion or the like) that is the same as the polymer electrolyte that constitutes the electrolyte membrane 112.

  The porous layers 122 and 124 are formed of carbon particles and resin particles made of a water repellent resin such as polytetrafluoroethylene (PTFE). The porous layers 122 and 124 have gas permeability and conductivity. The porous layers 122 and 124 including the water-repellent resin keep the moisture of the membrane / catalyst assembly 110 in an appropriate range and promote the discharge of excess moisture from the membrane / catalyst assembly 110.

  The gas diffusion layers 126 and 128 are conductive porous bodies, and serve as a flow path for a fuel gas containing hydrogen and an oxidizing gas containing oxygen, respectively. The gas diffusion layers 126 and 128 can be formed of a porous carbon material such as carbon paper or carbon felt, or various porous materials such as foam metal.

  The separators 130 and 140 are members having gas impermeability and conductivity. Separator 130,140 can be formed with various materials, such as compressed carbon, a titanium alloy, and stainless steel. The separators 130 and 140 of the first embodiment are flat members in which communication passages (not shown) for supplying fuel gas and oxidizing gas to the gas diffusion layers 126 and 128 are formed.

A2. Manufacturing process of membrane / catalyst assembly:
FIG. 2 is a process diagram showing a manufacturing process of the membrane / catalyst assembly 110. In the manufacturing process of the membrane / catalyst assembly 110 of the first embodiment, first, as shown in FIG. 2A, an electrolyte membrane HM whose thickness is ½ of the electrolyte membrane 112 (hereinafter referred to as “half-thick electrolyte membrane”). HM ”) is formed on the carrier film CF. Next, as shown in FIG. 2 (b), a catalyst layer CL to be the catalyst layers 114 and 116 of the membrane / catalyst assembly 110 is formed on the semi-thick electrolyte membrane HM formed on the carrier film CF.

  FIG. 3 is an explanatory diagram showing a configuration of a catalyst layer coating apparatus 500 for forming the catalyst layer CL on the half-thick electrolyte membrane HM. The catalyst layer coating apparatus 500 includes a raw material roll 510 winding a carrier film CF (hereinafter also referred to as “raw material film FU”) on which a half-thick electrolyte membrane HM is formed, and a coating for forming a catalyst layer CL. A coated roll 530 for winding up a work roll 520, a carrier film CF (hereinafter also referred to as “coated film FP”) on which a half-thick electrolyte membrane HM and a catalyst layer CL are formed; And a die 540 provided in the vicinity of the circumference.

  The raw material film FU supplied from the raw material roll 510 is adsorbed on the coating roll 520 so that the semi-thick electrolyte membrane HM is on the outer peripheral side. The adsorption of the raw material film FU is performed, for example, by reducing the pressure inside the suction holes (not shown) provided from the outer peripheral surface of the coating roll 520 toward the inside or by charging the coating roll 520. Can do.

  The die 540 applies the catalyst ink applied to the raw material film FU onto the half-thick electrolyte membrane HM of the raw material film FU adsorbed by the coating roll 520. Specifically, the pressurized catalyst ink is supplied to the die 540. The catalyst ink supplied to the die 540 is ejected from the die lip 542, and the catalyst ink is applied to the raw film FU adsorbed by the coating roll 520. In addition, as a catalyst ink, the dispersion liquid which disperse | distributed the carrier particle and electrolyte material in the mixed solvent of water and alcohol (for example, ethanol) can be used, for example.

  The catalyst ink applied to the raw material film FU is dried during the movement from the coating roll 520 to the coated roll 530 to form the catalyst layer CL. Thus, the coated film FP on which the catalyst layer CL is formed is wound around the coated roll 530. In addition, the processing method which processes the raw material film wound up by the raw material roll 510 in this way, and winds up the processed film on another roll is called a "roll-to-roll method." According to this roll-to-roll method, it becomes easier to process the film-like material, and the mass productivity of the processed film (the coated film FP in the first embodiment) is increased.

  In the first embodiment, the catalyst layer CL is formed on the half-thick electrolyte membrane HM of the raw material film FU by die coating using a die 540 to apply catalyst ink. However, the catalyst layer CL is formed by other methods. It is also possible to form For example, the catalyst layer CL can be formed by spray coating in which the catalyst ink is sprayed, or the catalyst layer CL can be formed by applying the catalyst ink using a doctor blade.

  As shown in FIG. 2C, the carrier film CF is peeled from the coated film thus formed. Then, as shown in FIG. 2D, the half-thick electrolyte membrane HM on which the catalyst layer CL is formed is joined so that the half-thick electrolyte membrane HM side is aligned, and the membrane / catalyst assembly 110 is formed. . The joining of the two half-thick electrolyte membranes HM can be performed by hot-pressing in which pressure is applied from the catalyst layer CL side while being heated to a predetermined temperature. Note that the temperature of the hot press is determined according to the characteristics of the electrolyte material. The temperature of the hot press can be determined based on, for example, the crystallization temperature of the electrolyte material, or can be determined experimentally.

A3. Manufacturing process of membrane / electrode assembly:
FIG. 4 is a process diagram showing a manufacturing process of the membrane-electrode assembly 120 (FIG. 1). In the manufacturing process of the membrane / electrode assembly, first, as shown in FIG. 4A, a gas diffusion layer GDL to be the gas diffusion layers 126 and 128 of the membrane / electrode assembly 120 is prepared. Next, an ink in which carbon particles and resin particles are dispersed is applied onto the prepared gas diffusion layer GDL and baked. Thereby, as shown in FIG. 4B, the porous layer MPL to be the porous layers 122 and 124 of the membrane-electrode assembly 120 is formed on the gas diffusion layer GDL.

  FIG. 4C shows the membrane / catalyst assembly 110 manufactured in the manufacturing process of FIG. By sandwiching the membrane / catalyst assembly 110 with a gas diffusion layer GDL in which a porous layer MPL is formed as shown in FIG. 4 (d), the membrane / electrode assembly is shown in FIG. 4 (e). A body 120 is formed.

A4. Comparative Example 1:
FIG. 5 is a process diagram showing a comparative example of the manufacturing process of the membrane / electrode assembly 120. In this comparative example, a gas diffusion layer GDL is prepared as shown in FIGS. 5 (a) and 5 (b), similar to the manufacturing process of the membrane-electrode assembly 120 of the first embodiment shown in FIG. The porous layer MPL is formed on the prepared gas diffusion layer GDL.

  Next, as shown in FIG. 5C, the catalyst layer CL is formed on the porous layer MPL. The gas diffusion layer GDL in which the catalyst layer CL and the porous layer MPL are formed is joined to the electrolyte membrane 112 (FIG. 5D) prepared in advance as shown in FIG. A joined body 120 is formed.

  In the comparative example of FIG. 5, the catalyst layer CL is formed on the porous layer MPL. Formation of the catalyst layer CL is performed by applying the catalyst ink and drying the applied catalyst ink in the same manner as in the first embodiment. At the application stage of the catalyst ink, the catalyst ink soaks into the porous layer MPL. Therefore, the amount of the catalyst ink used for forming the catalyst layer CL is increased as compared with the first embodiment in which the catalyst ink is applied onto the half-thick electrolyte membrane HM.

  In the comparative example of FIG. 5, when the gas diffusion layer GDL in which the porous layer MPL and the catalyst layer CL are formed is formed of a porous carbon material, the gas diffusion layer GDL becomes brittle and the gas diffusion layer GDL is rolled. It becomes difficult to do. Therefore, it becomes difficult to use the roll-to-roll method as in the first embodiment, and the mass productivity is lower than that in the first embodiment.

A5. Comparative Example 2:
FIG. 6 is a process diagram showing a comparative example of the manufacturing process of the membrane / catalyst assembly 110. In this comparative example, the membrane / catalyst assembly 110 is formed by a transfer method in which the catalyst layer CL is transferred to both surfaces of the electrolyte membrane 112.

  In this comparative example, as shown in FIG. 6A and FIG. 6B, a carrier film CFC for forming the catalyst layer CL and a carrier film CFM for forming the electrolyte membrane 112 are prepared. . Next, as shown in FIGS. 6C and 6D, a catalyst layer CL and an electrolyte membrane 112 are formed on the carrier films CFC and CFM, respectively. Formation of the catalyst layer CL is performed by applying a catalyst ink on the carrier film CFC and drying the applied catalyst ink. Formation of the electrolyte membrane 112 is performed by applying an electrolyte solution on the carrier film CFM and drying the applied electrolyte solution.

  As shown in FIG. 6E, the catalyst layer CL formed on the carrier film CFC is transferred to the electrolyte membrane 112 peeled from the carrier film CFM (FIG. 6D), and the membrane / catalyst assembly 110 is transferred. Is formed (FIG. 6F). At this time, the catalyst layer CL is joined to the electrolyte membrane 112 from the surface opposite to the carrier film CFC.

  As described above, in the comparative example of FIG. 6, the catalyst layer CL is formed by drying the catalyst ink applied on the carrier film CFC. In the drying stage of the catalyst ink, the liquid level of the catalyst ink moves to the carrier film CFC side by evaporating water and alcohol in the catalyst ink. For this reason, depending on the drying conditions of the catalyst ink, the carrier particles and the electrolyte material in the catalyst ink are unevenly distributed on the carrier film CFC side.

  If the electrolyte material on the side opposite to the electrolyte membrane 112 of the catalyst layer CL (ie, the porous layers 122 and 124 in FIG. 1) increases due to uneven distribution, gas diffusion in the catalyst layer CL is inhibited. As described above, when the diffusion of the gas in the catalyst layer CL is inhibited, the reaction amount of the gas supplied to the catalyst layer CL is lowered, and the characteristics of the fuel cell 100 are lowered. On the other hand, in the first embodiment, the catalyst layer CL is formed on the semi-thick electrolyte membrane HM, so that even if uneven distribution occurs, the carrier particles and the electrolyte material increase on the electrolyte membrane 112 side. Therefore, the gas diffusibility in the catalyst layer CL can be maintained sufficiently high, and the deterioration of the characteristics of the fuel cell 100 is suppressed.

  In addition, the carrier film used for forming the membrane / catalyst assembly 110 may be two carrier films CF for forming the half-thick electrolyte membrane HM in the first embodiment, whereas FIG. In the comparative example, two carrier films CFC for forming the catalyst layer CL and one carrier film CFM for forming the electrolyte membrane 112 are required.

A6. Effects of the first embodiment:
In the first embodiment, the catalyst layer CL is formed by forming the half-thick electrolyte film HM on the carrier film CF and applying the catalyst ink on the half-thick electrolyte film HM formed on the carrier film CF. The membrane / catalyst assembly 110 is formed by joining the semi-thick electrolyte membranes HM on which the catalyst layer CL is formed.

  Thus, in the first embodiment, the application of the catalyst ink for forming the catalyst layer CL is performed on the half-thick electrolyte membrane HM formed on the carrier film CF. Therefore, the swelling / shrinkage of the electrolyte membrane due to the catalyst ink solvent generated when the catalyst ink is applied to the electrolyte membrane 112 itself is suppressed, and the catalyst layer CL can be formed by a roll-to-roll method with high mass productivity. It becomes. Further, since the catalyst layer CL formed by applying the catalyst ink on the half-thick electrolyte membrane HM has high adhesion to the half-thick electrolyte membrane HM, proton conductivity in the membrane-catalyst assembly 110 is high. Become. Therefore, the characteristics of the fuel cell 100 are improved by applying the first embodiment to the manufacture of the membrane / catalyst assembly 110. Furthermore, it is possible to maintain high mass productivity and suppress deterioration of the characteristics of the fuel cell 100 as compared with a manufacturing method in which the catalyst ink is not applied to the electrolyte membrane 112 itself.

  In the first embodiment, the thickness of the half-thick electrolyte membrane HM formed on the carrier film CF is set to 1/2 the thickness of the electrolyte membrane 112. Therefore, as shown in FIGS. 2 (c) and 2 (d), the electrolyte membranes are joined by joining the membranes having the same configuration in which the catalyst layer CL is formed on the half-thick electrolyte membrane HM. Is called. However, the thickness of the electrolyte membrane to be joined is not limited to 1/2 the thickness of the electrolyte membrane 112 as long as the electrolyte membrane 112 having a predetermined thickness is formed by joining. For example, the thickness of one electrolyte membrane may be 1/3 of the thickness of the electrolyte membrane 112, and the thickness of the other electrolyte membrane may be 2/3 of the thickness of the electrolyte membrane 112. However, since it is possible to improve the production efficiency by mass production by joining the membranes having the same structure, it is more preferable that the thickness of the electrolyte membrane formed on the carrier film CF is 1/2 that of the electrolyte membrane 112. .

  In the first embodiment, the semi-thick electrolyte membrane HM and the catalyst layer CL are formed on the flexible carrier film CF, but on a non-flexible substrate such as a resin or metal plate. The semi-thick electrolyte membrane HM and the catalyst layer CL may be formed. Even in this case, the swelling and shrinkage of the electrolyte membrane due to the solvent of the catalyst ink is suppressed, and the application of the catalyst ink becomes easier. However, it is more preferable to use a flexible base material such as the carrier film CF in that a roll-to-roll method with high mass productivity can be used.

  It is also possible to form the catalyst layer CL by applying a catalyst ink to the half-thick electrolyte membrane HM itself without using a substrate. In this case, in order to suppress the swelling / shrinkage of the electrolyte membrane, the catalyst layer CL is formed by a method of laminating the catalyst ink in a plurality of times or a method of applying a high-viscosity catalyst ink. When the catalyst ink is laminated in a plurality of times, the time required for forming the catalyst layer CL increases, and when applying a highly viscous catalyst ink, it becomes difficult to apply the catalyst ink uniformly. . Therefore, it is more preferable to apply the catalyst ink on the half-thick electrolyte membrane HM formed on the substrate to form the catalyst layer CL.

B. Second embodiment:
FIG. 7 is a schematic cross-sectional view showing the membrane / catalyst assembly 110a of the second embodiment. The membrane / catalyst assembly 110a of the second embodiment is different from the membrane / catalyst assembly 110 of the first embodiment in that a protective film PF is provided around the catalyst layer CL. Other points are the same as in the first embodiment.

  The protective film PF is a frame-like film provided with holes having almost the same size as the catalyst layer CL. This protective film PF is attached when the half-thick electrolyte membranes HM are joined by hot-pressing or after joining the half-thick electrolyte membranes HM by hot-pressing.

  The membrane / catalyst assembly 110a of the second embodiment can increase the strength of the membrane / catalyst assembly 110a by providing the protective film PF, and suppress damage to the formed membrane / catalyst assembly 110a. It becomes possible. Moreover, it becomes possible to suppress that the catalyst layers CL short-circuit by arrange | positioning the protective film PF around the catalyst layer CL.

DESCRIPTION OF SYMBOLS 100 ... Fuel cell 110, 110a ... Membrane / catalyst assembly 112 ... Electrolyte membrane 114, 116 ... Catalyst layer 120 ... Membrane / electrode assembly 122, 124 ... Porous layer 126, 128 ... Gas diffusion layer 130, 140 ... Separator 500 ... Catalyst layer coating apparatus 510 ... Raw material roll 520 ... Coating roll 530 ... Coated roll 540 ... Die 542 ... Die lip CF, CFC, CFM ... Carrier film CL ... Catalyst layer FP ... Coated film FU ... Raw material film GDL ... Gas diffusion layer HM ... Semi-thick electrolyte membrane MPL ... Porous layer PF ... Protective film

Claims (7)

A method for producing a membrane / catalyst assembly having an electrolyte membrane having a predetermined thickness and a catalyst layer formed on both surfaces of the electrolyte membrane,
Forming the catalyst layer by applying a catalyst ink on one surface of the first electrolyte membrane thinner than the predetermined thickness;
Forming the catalyst layer by applying the catalyst ink on one surface of a second electrolyte membrane having a thickness obtained by subtracting the thickness of the first electrolyte membrane from the predetermined thickness;
A method for producing a membrane / catalyst assembly, wherein the first electrolyte membrane and the second electrolyte membrane are joined. A method for producing a membrane-catalyst assembly according to claim 1,
Each of the first and second electrolyte membranes is formed on a substrate,
The said catalyst layer is formed by apply | coating the said catalyst ink to the surface on the opposite side to the said base material. The manufacturing method of a film | membrane and catalyst assembly.   The method for producing a membrane / catalyst assembly according to claim 2, wherein the substrate has flexibility.   The method of manufacturing a membrane / catalyst assembly according to any one of claims 1 to 3, wherein a thickness of the first and second electrolyte membranes is ½ of the predetermined thickness. A method for producing a membrane / catalyst assembly according to any one of claims 1 to 4, further comprising:
A method for producing a membrane / catalyst assembly, wherein a protective film is provided on an outer edge of the catalyst layer of the membrane / catalyst assembly. A membrane-catalyst assembly,
An electrolyte membrane having a predetermined thickness; and catalyst layers formed on both sides of the electrolyte membrane,
The membrane / catalyst assembly is
Forming the catalyst layer by applying a catalyst ink on one surface of the first electrolyte membrane thinner than the predetermined thickness;
Forming the catalyst layer by applying the catalyst ink on one surface of a second electrolyte membrane having a thickness obtained by subtracting the thickness of the first electrolyte membrane from the predetermined thickness;
A membrane / catalyst assembly produced by joining the first electrolyte membrane and the second electrolyte membrane. A fuel cell,
A membrane / catalyst assembly having an electrolyte membrane of a predetermined thickness and a catalyst layer formed on both surfaces of the electrolyte membrane;
An oxidizing gas supply passage for supplying an oxidizing gas to one catalyst layer of the membrane-catalyst assembly;
A fuel gas supply flow path for supplying fuel gas to the other catalyst layer of the membrane-catalyst assembly,
The membrane / catalyst assembly is
Forming the catalyst layer by applying a catalyst ink on one surface of the first electrolyte membrane thinner than the predetermined thickness;
Forming the catalyst layer by applying the catalyst ink on one surface of a second electrolyte membrane having a thickness obtained by subtracting the thickness of the first electrolyte membrane from the predetermined thickness;
A fuel cell manufactured by joining the first electrolyte membrane and the second electrolyte membrane.

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