JP6354126B2 - Membrane electrode assembly and manufacturing method thereof - Google Patents

Description

  The present invention relates to a membrane electrode assembly for a polymer electrolyte fuel cell and a method for producing the same.

  A fuel cell is a power generation engine that generates electricity from an electrochemical reaction between hydrogen and oxygen, has high power generation efficiency, and discharges only water during power generation, and is expected as a next-generation power source. A membrane electrode assembly of a polymer electrolyte fuel cell has a pair of electrode catalyst layers (hereinafter also simply referred to as “catalyst layers”) on both sides of a polymer electrolyte membrane (hereinafter also simply referred to as “electrolyte membrane”). It is a joined structure. A fuel cell is used in which a gas diffusion layer is disposed outside the catalyst layer of the membrane electrode assembly and is further sandwiched between separators.

A transfer method is known as a method for producing a membrane electrode assembly. In the transfer method, a transfer sheet having a catalyst layer formed by applying a catalyst ink containing a catalyst-supporting carbon, an ionomer, and a solvent on a substrate such as a polymer film and drying is prepared, and the transfer sheet is used as an electrode. This is a method of thermocompression bonding by cutting and cutting the polymer electrolyte membrane and applying heat and pressure to the polymer electrolyte membrane. In this method, since the catalyst ink is not directly applied to the electrolyte membrane or the gas diffusion layer, the electrolyte membrane does not swell and the gas diffusion layer is not clogged.
As a method for forming a catalyst layer having a desired shape on the electrolyte membrane, a transfer sheet having a catalyst layer having a size larger than the desired electrode shape is prepared, and a mask film having an opening having a desired shape is used as the electrolyte membrane. A method of manufacturing a membrane electrode assembly by a transfer method by inserting between a transfer sheet and a transfer sheet is known. (For example, Patent Document 1)

Further, a gasket for the purpose of preventing gas leak is disposed around the membrane electrode assembly. This gasket is required to support the electrolyte membrane and contribute to the suppression of oxygen and hydrogen leakage and the maintenance of the humidity of the electrolyte membrane. Furthermore, in order to suppress deterioration due to exposure of the electrolyte membrane, it is desirable that the gasket disposed around the catalyst layer is disposed without a gap from the catalyst layer.
As a method for arranging the gasket without any gap from the catalyst layer, a method by injection molding is known. In this method, a membrane electrode assembly is incorporated into a mold, and a gasket is disposed around the membrane electrode assembly by filling and solidifying a gasket material in a cavity in the mold. (For example, Patent Document 2)

JP 2006-244930 A JP 2002-42836 A

However, in the transfer method using the above-described mask film, it is necessary to remove the mask film after the transfer of the catalyst layer as a pre-process for disposing the gasket, and in that case, a part of the catalyst layer may be peeled off. . As a result, the reproducibility of the electrode shape is deteriorated, and a gap is formed between the gasket and the opening having a desired shape, which causes deterioration of the electrolyte membrane.
In addition, the above-described gasket placement by injection molding is disadvantageous in terms of cost because it requires an increase in the number of processes and a mold. Furthermore, when the liquid gasket is cured, the electrolyte membrane may deteriorate due to overheating.
The present invention has been made in order to solve the above-mentioned problems, and compared with the prior art, a membrane electrode assembly having no gap between the catalyst layer and the gasket with a smaller number of steps and parts and a method for producing the same The purpose is to provide.

One aspect of the present invention includes an arrangement step of disposing a gasket having an opening on an electrolyte membrane, and a transfer step of transferring a catalyst layer formed on a transfer sheet onto the electrolyte membrane in the opening. The method for producing a membrane / electrode assembly is characterized in that the size of the catalyst layer formed on the transfer sheet is equal to or larger than the size of the opening of the gasket.
Moreover, in the manufacturing method of the membrane electrode assembly, the thickness dimension of the catalyst layer formed on the transfer sheet may be the same as the thickness dimension of the gasket.

According to another aspect of the present invention, there is provided a disposing step of disposing a gasket having an opening on the electrolyte membrane, and a catalyst layer containing a solvent, the size of the catalyst layer being larger than the size of the opening of the gasket. A forming step of forming on the transfer sheet, a pre-drying step of removing part of the solvent from the catalyst layer and drying the catalyst layer after the forming step, and after the pre-drying step A transfer step of transferring the catalyst layer onto the electrolyte membrane in the opening, and in the preliminary drying step, a pressing force when transferring the catalyst layer onto the electrolyte membrane in the transfer step; The method for producing a membrane electrode assembly is characterized in that the amount of residual solvent in the catalyst layer is adjusted so that the shape of the catalyst layer changes at the same pressing force.
In the method for manufacturing a membrane electrode assembly, in the transfer step, the pair of catalyst layers may be simultaneously transferred onto the front and back of the electrolyte membrane.
Another aspect of the present invention is a membrane electrode assembly for use in a fuel cell, which is manufactured by the method for manufacturing a membrane electrode assembly described above.

According to one aspect of the present invention, the gasket having the opening is formed on the electrolyte membrane, and the catalyst layer formed on the transfer sheet is transferred onto the electrolyte membrane in the opening. Further, the size of the catalyst layer formed on the transfer sheet is set to be larger than the size of the opening of the gasket.
According to this configuration, since the size of the catalyst layer formed on the transfer sheet is equal to or larger than the size of the opening of the gasket, the catalyst layer and the gasket are reduced in the number of processes and parts compared to the prior art. Membrane / electrode assembly with no gap between the two can be produced.

It is a schematic sectional drawing of the membrane electrode assembly in the polymer electrolyte fuel cell which concerns on 1st embodiment of this invention. It is a manufacturing-process figure of the membrane electrode assembly in the polymer electrolyte fuel cell which concerns on 1st embodiment of this invention. It is another manufacturing-process figure of the membrane electrode assembly in the polymer electrolyte fuel cell which concerns on 1st embodiment of this invention. It is one manufacturing-process figure of the membrane electrode assembly in the polymer electrolyte fuel cell which concerns on 2nd embodiment of this invention. It is another manufacturing-process figure of the membrane electrode assembly in the polymer electrolyte fuel cell which concerns on 2nd embodiment of this invention. It is a schematic sectional drawing of the membrane electrode assembly in the polymer electrolyte fuel cell which concerns on 2nd embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
<About membrane electrode assembly>
A membrane electrode assembly 10 and a manufacturing method thereof in a polymer electrolyte fuel cell according to a first embodiment of the present invention will be described in detail with reference to FIG.
FIG. 1 is a schematic cross-sectional view of a membrane electrode assembly 10 in a polymer electrolyte fuel cell according to a first embodiment of the present invention. As shown in FIG. 1, a membrane electrode assembly 10 according to the first embodiment of the present invention includes an electrolyte membrane 11 and a cathode side catalyst disposed on one surface (upper surface in FIG. 2) of the electrolyte membrane 11. A layer 13a, and an anode side catalyst layer 13b disposed on the other surface (the lower surface in FIG. 2) of the electrolyte membrane 11. Further, a cathode side gasket 12a and an anode side gasket 12b are disposed on the electrolyte membrane 11 and around the cathode side catalyst layer 13a and the anode side catalyst layer 13b, respectively.

<About the manufacturing method of a membrane electrode assembly>
The manufacturing method of the membrane electrode assembly in the polymer electrolyte fuel cell according to the first embodiment of the present invention will be described in detail with reference to FIGS.
First, a cathode side gasket 22 a having an opening of a desired size is disposed on the electrolyte membrane 21. If necessary, an adhesive material or an adhesive material may be filled between the electrolyte membrane 21 and the cathode side gasket 22a to form the cathode side adhesive layer or adhesive layer 23a.
Subsequently, the cathode side catalyst layer 24a is formed on the cathode side transfer sheet 25a. In forming the cathode-side catalyst layer 24a, first, an ink (catalyst ink) including a polymer electrolyte, a catalyst material, a carbon carrier supporting the catalyst material, and a dispersion medium is prepared. The prepared catalyst ink is applied onto the cathode side transfer sheet 25a by using, for example, a doctor blade method, a dipping method, a screen printing method, a roll coating method, a spraying method, or a spray method. A catalyst layer 24a is formed.

The shape of the cathode side catalyst layer 24a formed on the cathode side transfer sheet 25a is not particularly specified, but the size (for example, width dimension) of the cathode side catalyst layer 24a is the size of the opening of the cathode side gasket 22a (for example, 2-10 mm larger than the width dimension). By using the catalyst layer having such a size, it is possible to prevent a gap from being formed between the cathode side gasket 22a and the cathode side catalyst layer 24a when the cathode side catalyst layer 24a is transferred onto the electrolyte membrane 21. The size of the cathode side catalyst layer 24a formed on the cathode side transfer sheet 25a may be equal to or larger than the size of the opening of the cathode side gasket 22a. Further, the thickness dimension of the cathode side catalyst layer 24a formed on the cathode side transfer sheet 25a may be the same as the thickness dimension of the cathode side gasket 22a.
The electrolyte membrane 21 on which the cathode side gasket 22a is disposed and the cathode side transfer sheet 25a on which the cathode side catalyst layer 24a is formed are laminated, and the cathode side catalyst layer 24a is formed on the electrolyte membrane 21 by transfer.

Subsequently, as shown in FIG. 3, an anode side gasket 22b having an opening of a desired size on the surface opposite to the surface of the electrolyte membrane 21 on which the cathode side catalyst layer 24a is formed (upper surface in FIG. 3). Place. If necessary, an adhesive material or an adhesive material may be filled between the electrolyte membrane 21 and the anode side gasket 22b to form the anode side adhesive layer or the adhesive layer 23b.
Subsequently, an anode side catalyst layer 24b is formed on the anode side transfer sheet 25b. In forming the anode-side catalyst layer 24b, first, an ink (catalyst ink) including a polymer electrolyte, a catalyst material, a carbon carrier supporting the catalyst material, and a dispersion medium is prepared. The prepared catalyst ink is applied onto the anode-side transfer sheet 25b by using, for example, a doctor blade method, a dipping method, a screen printing method, a roll coating method, a spraying method, or a spraying method. A catalyst layer 24b is formed.

The shape of the anode side catalyst layer 24b formed on the anode side transfer sheet 25b is not particularly specified, but the size (for example, width dimension) of the anode side catalyst layer 24b is the size of the opening of the anode side gasket 22b (for example, 2-10 mm larger than the width dimension). By setting the catalyst layer to such a size, it is possible to prevent a gap from being generated between the anode side gasket 22b and the anode side catalyst layer 24b when the anode side catalyst layer 24b is transferred onto the electrolyte membrane 21. The size of the anode side catalyst layer 24b formed on the anode side transfer sheet 25b may be larger than the size of the opening of the anode side gasket 22b. Further, the thickness dimension of the anode side catalyst layer 24b formed on the anode side transfer sheet 25b may be the same as the thickness dimension of the anode side gasket 22b.
The electrolyte membrane 21 on which the anode side gasket 22b is arranged and the anode side transfer sheet 25b on which the anode side catalyst layer 24b is formed are laminated, and the anode side catalyst layer 24b is formed on the electrolyte membrane 21 by transfer, and the target membrane electrode Obtain a zygote.

  In this embodiment, the cathode side catalyst layer 24a is first transferred to the electrolyte membrane 21, and then the anode side catalyst layer 24b is transferred to the electrolyte membrane 21. However, the present invention is not limited to this. For example, the anode side catalyst layer 24 b may be transferred to the electrolyte membrane 21 first, and then the cathode side catalyst layer 24 a may be transferred to the electrolyte membrane 21. In order to reduce damage to the electrolyte membrane 21 due to heat, a pair of catalyst layers are simultaneously transferred to the front and back of the electrolyte membrane 21 (that is, the cathode side surface and the anode side surface), and the cathode side catalyst layer 24a and the anode It is desirable to form the side catalyst layer 24b simultaneously.

FIG. 4 is a manufacturing process diagram of the membrane electrode assembly 30 in the polymer electrolyte fuel cell according to the second embodiment of the present invention.
First, a cathode side gasket 32 a having an opening of a desired size is disposed on the electrolyte membrane 31. If necessary, an adhesive material or an adhesive material may be filled between the electrolyte membrane 31 and the cathode side gasket 32a to form the cathode side adhesive layer or adhesive layer 33a.
Subsequently, a cathode side catalyst layer 34a is formed on the cathode side transfer sheet 35a. In forming the cathode side catalyst layer 34a, first, an ink (catalyst ink) including a polymer electrolyte, a catalyst material, a carbon carrier supporting the catalyst material, and a dispersion medium is prepared. The prepared catalyst ink is applied on the cathode side transfer sheet 35a by using, for example, a doctor blade method, a dipping method, a screen printing method, a roll coating method, a spraying method, or a spray method. A catalyst layer 34a is formed.

At this time, the size (for example, width dimension) of the cathode side catalyst layer 34a applied on the cathode side transfer sheet 35a is smaller by about 1 mm than the size (for example, width dimension) of the opening of the cathode side gasket 32a. It is desirable to form the cathode side catalyst layer 34a thicker than the cathode side gasket 32a. In addition, an amount of organic solvent that can change the shape of the cathode side catalyst layer 34a by pressing is left in the cathode side catalyst layer 34a, so that the cathode side catalyst is formed into the opening shape of the cathode side gasket 32a at the time of transfer. The shape of the layer 34a is preferably changed. In other words, the residual solvent amount in the cathode side catalyst layer 34a is set so that the shape of the cathode side catalyst layer 34a changes at the same pressing force as when the cathode side catalyst layer 34a is transferred onto the electrolyte membrane 31. It is preferable to adjust. Here, the “residual solvent amount” refers to the total amount of water and solvent remaining in the catalyst layer, and it is preferable that 20% or more remain with respect to the mass of the catalyst layer. Thereby, the cathode side catalyst layer 34a can be formed in the cathode side gasket 32a without a gap. Before transferring the cathode side catalyst layer 34a to the electrolyte membrane 31, a part of the solvent (for example, organic solvent) contained in the cathode side catalyst layer 34a coated on the cathode side transfer sheet 35a is removed, The cathode side catalyst layer 34a may be dried (preliminary drying step).
The electrolyte membrane 31 on which the cathode side gasket 32a is disposed and the cathode side transfer sheet 35a on which the cathode side catalyst layer 34a is formed are laminated, and the cathode side catalyst layer 34a is formed on the electrolyte membrane 31 by transfer.

Subsequently, as shown in FIG. 5, an anode side gasket 32b having an opening of a desired size on the surface opposite to the surface of the electrolyte membrane 31 on which the cathode side catalyst layer 34a is formed (upper surface in FIG. 5). Place. If necessary, an adhesive material or an adhesive material may be filled between the electrolyte membrane 31 and the anode side gasket 32b to form the anode side adhesive layer or the adhesive layer 33b.
Subsequently, an anode side catalyst layer 34b is formed on the anode side transfer sheet 35b. In forming the anode side catalyst layer 34b, first, an ink (catalyst ink) including a polymer electrolyte, a catalyst material, a carbon carrier supporting the catalyst material, and a dispersion medium is prepared. The prepared catalyst ink is applied onto the anode-side transfer sheet 35b by using, for example, a doctor blade method, a dipping method, a screen printing method, a roll coating method, a spraying method, or a spraying method. A catalyst layer 34b is formed.

At this time, the size (for example, width dimension) of the anode side catalyst layer 34b applied on the anode side transfer sheet 35b is smaller by about 1 mm than the size (for example, width dimension) of the opening of the anode side gasket 32b. It is desirable that the anode-side catalyst layer 34b be formed thicker than the anode-side gasket 32b. Further, by leaving an amount of an organic solvent in the anode side catalyst layer 34b so that the shape of the anode side catalyst layer 34b can be changed by the pressing, the anode side catalyst is formed into the shape of the opening of the anode side gasket 32b at the time of transfer. It is preferable that the shape of the layer 34b changes. In other words, the amount of residual solvent in the anode side catalyst layer 34b is set so that the shape of the anode side catalyst layer 34b changes at the same pressing force as when the anode side catalyst layer 34b is transferred onto the electrolyte membrane 31. It is preferable to adjust so that it may become 20% or more. Thereby, the anode side catalyst layer 34b can be formed in the anode side gasket 32b without a gap. Before transferring the anode side catalyst layer 34b to the electrolyte membrane 31, a part of the solvent (for example, organic solvent) contained in the anode side catalyst layer 34b applied on the anode side transfer sheet 35b is removed, The anode side catalyst layer 34b may be dried (preliminary drying step).
The electrolyte membrane 31 on which the anode side gasket 32b is arranged and the anode side transfer sheet 35b on which the anode side catalyst layer 34b is formed are laminated, and the anode side catalyst layer 34b is formed on the electrolyte membrane 31 by transfer, and the target membrane electrode A joined body 30 is obtained.

  In the present embodiment, the case where the cathode side catalyst layer 34a is first transferred to the electrolyte membrane 31 and then the anode side catalyst layer 34b is transferred to the electrolyte membrane 31 has been described. However, the present invention is not limited to this. For example, the anode side catalyst layer 34 b may be transferred to the electrolyte membrane 31 first, and then the cathode side catalyst layer 34 a may be transferred to the electrolyte membrane 31. In addition, in order to reduce damage to the electrolyte membrane 31 due to heat, a pair of catalyst layers are simultaneously transferred onto the front and back of the electrolyte membrane 31 (that is, the cathode side surface and the anode side surface), and the cathode side catalyst layer 34a and anode It is desirable to form the side catalyst layer 34b at the same time.

<About electrolyte membrane>
The electrolyte membranes 11, 21, and 31 used in the present embodiment may be those generally used for polymer electrolyte fuel cells. For example, a fluorine-based electrolyte membrane or a hydrocarbon electrolyte membrane can be suitably used, and a fluorine-based electrolyte membrane is particularly desirable. Examples of the fluorine-based polymer electrolyte membrane include Nafion (registered trademark, manufactured by DuPont), Flemion (registered trademark, manufactured by Asahi Glass Co., Ltd.), Aciplex (registered trademark, manufactured by Asahi Kasei Corporation), Gore Select (registered trademark, Gore). Etc.) can be used. As the hydrocarbon polymer electrolyte membrane, for example, electrolyte membranes such as sulfonated polyether ketone, sulfonated polyethersulfone, sulfonated polyetherethersulfone, sulfonated polysulfide, and sulfonated polyphenylene can be used.

<About the catalyst layer>
The cathode side catalyst layers 12a, 24a, 34a and the anode side catalyst layers 12b, 24b, 34b may also be those generally used for solid polymer fuel cells. For example, platinum or fine particles (average particle size) of platinum and another metal (for example, ruthenium (Ru), rhodium (Rh), molybdenum (Mo), chromium (Cr), cobalt (Co), iron (Fe), etc.)) The diameter is preferably 10 nm or less), conductive carbon fine particles such as carbon black supported on the surface (the average particle diameter is preferably about 20 nm to 100 nm), and a polymer solution such as a perfluorosulfonic acid resin solution. In addition, those prepared by ink uniformly mixed in an appropriate solvent (for example, ethanol) can be used.

  If the average particle size of the conductive carbon fine particles is too small, it becomes difficult to form an electron conduction path. Moreover, when too large, there exists a possibility that the gas diffusibility of a catalyst layer may fall and the utilization factor of a catalyst may fall. For this reason, the average particle diameter of the conductive carbon fine particles is preferably about 20 nm to 100 nm. Any suitable solvent may be used as long as it can dissolve or disperse the polymer electrolyte and the catalyst substance, but a solvent that is easily removed by evaporation at room temperature or heating is preferable. For example, a solvent having a boiling point of 200 ° C. or lower is preferable. In the present embodiment, the solvent may be an organic solvent.

<About gaskets>
The cathode side gaskets 12a, 22a, and 32a and the anode side gaskets 12b, 22b, and 32b may be those generally used for polymer electrolyte fuel cells. For example, PET (polyethylene terephthalate), PEN (polyethylene naphthalate), SPS (syndiotactic polystyrene), PTFE (polytetrafluoroethylene), PI (polyimide) and the like can be used. The cathode side gaskets 12a, 22a, 32a and the anode side gaskets 12b, 22b, 32b are preferably a single film or sheet. However, if necessary, a film or sheet in which a plurality of layers are laminated may be adopted as the single side film or sheet for the cathode side gaskets 12a, 22a, 32a and the anode side gaskets 12b, 22b, 32b.

<Adhesive layer or adhesive layer>
The cathode side gaskets 12a, 22a, 32a and the anode side gaskets 12b, 22b, 32b are disposed on the surfaces of the electrolyte membranes 21, 31 using an adhesive layer or adhesive layers 23a, 23b, 33a, 33b as necessary. . Examples of the pressure-sensitive adhesive material and adhesive material used when forming the pressure-sensitive adhesive layer or the adhesive layers 23a, 23b, 33a, and 33b include materials such as a polysiloxane skeleton, a polyether skeleton, a fluoroether skeleton, and a polyolefin skeleton. Can be used. Further, as described above, the pressure-sensitive adhesive layers or adhesive layers 23a, 23b, 33a, 33b are disposed on the electrolyte membranes 21, 31. Therefore, in order to prevent the electrolyte membranes 21 and 31 from swelling due to the solvent contained in the adhesive layer or the adhesive layers 23a, 23b, 33a and 33b, the adhesive layer or adhesive layers 23a, 23b, 33a and 33b must A solvent system is desirable.

Hereinafter, the membrane electrode assembly of the polymer electrolyte fuel cell of the present embodiment and the manufacturing method thereof will be described by way of specific examples. In addition, the Example mentioned later is an Example of one Embodiment of this invention, and this invention is not limited only to this Example.
A platinum-supported carbon catalyst (trade name: TEC10E50E, manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) with a platinum loading of 50% and a polymer electrolyte solution Nafion (registered trademark, manufactured by DuPont) with a mass of 20% are used as a solvent (water, 1 -Propanol, 2-propanol = 1: 1: 1 (volume ratio)) and dispersed using a planetary ball mill (Pulverisete 7 manufactured by FRITSCH) (ball mill pot, balls are manufactured by zirconia). To prepare a catalyst ink. The solid content in the catalyst ink thus prepared was 10% by weight.

The catalyst ink was applied to the transfer sheet by the doctor blade method, and the catalyst ink applied onto the transfer sheet was dried in an air atmosphere at a temperature of 80 ° C. for 5 minutes, whereby the cathode-side catalyst layer of the example and Anode catalyst layers were obtained. At this time, the thickness of the cathode side catalyst layer and the anode side catalyst layer was adjusted so that the supported amount of the catalyst substance Pt was 0.4 mg / cm ² .

  Subsequently, a fluoroether type adhesive is applied to the gasket film obtained by punching a square of 50 mm square by screen printing so as to have a thickness of 35 μm, and is applied to an electrolyte membrane of Nafion (registered trademark) XL (made by DuPont). It was. Two transfer sheets and an electrolyte membrane were disposed on the electrolyte membrane so that the cathode-side catalyst layer and the anode-side catalyst layer and each surface of the electrolyte membrane face each other. Thereafter, the electrolyte membrane sandwiched between these two transfer sheets was heated to 130 ° C., and hot-pressed for 10 minutes under pressure. Thus, a membrane electrode assembly including the electrolyte membrane, the cathode side catalyst layer, and the anode side catalyst layer in this example was obtained.

  INDUSTRIAL APPLICABILITY The present invention can be suitably used for a polymer electrolyte fuel cell single cell or a stack in a polymer electrolyte fuel cell, particularly a fuel cell automobile or a household fuel cell.

DESCRIPTION OF SYMBOLS 10 ... Membrane electrode assembly 11 ... Electrolyte membrane 12a ... cathode side gasket 12b ... anode side gasket 13a ... cathode side catalyst layer 13b ... anode side catalyst layer 21 ... electrolyte membrane 22a ... cathode Side gasket 22b ·· Anode side gasket 23a ·· Cathode side adhesive layer or adhesive layer 23b ·· Anode side adhesive layer or adhesive layer 24a ·· Cathode side catalyst layer 24b ·· Anode side catalyst layer 25a ·· Cathode side transfer sheet 25b Anode transfer sheet 30 Membrane electrode assembly 31 Electrolyte membrane 32a Cathode side gasket 32b Anode side gasket 33a Cathode side adhesive layer or adhesive layer 33b Anode side adhesive layer or Adhesive layer 34a ... Cathode side catalyst layer 34b ... Anode side adhesive layer or adhesive layer 35a ... The cathode side transfer sheet 35b ·· anode side of the transfer sheet

Claims (2)

An arrangement step of disposing a gasket having an opening on the electrolyte membrane;
Forming a solvent-containing catalyst layer on the transfer sheet such that the size of the catalyst layer is smaller than the size of the opening of the gasket;
After the forming step, a preliminary drying step of removing a part of the solvent from the catalyst layer and drying the catalyst layer;
A transfer step of transferring the catalyst layer onto the electrolyte membrane in the opening after the preliminary drying step;
In the preliminary drying step, the amount of residual solvent in the catalyst layer is changed so that the shape of the catalyst layer changes when the pressing force is the same as the pressing force when the catalyst layer is transferred onto the electrolyte membrane in the transfer step. Adjust
The method for producing a membrane electrode assembly, wherein the catalyst layer obtained after the transfer step is formed without gaps in the opening.   2. The method for producing a membrane electrode assembly according to claim 1, wherein in the transfer step, the pair of catalyst layers are simultaneously transferred onto the front and back of the electrolyte membrane.

Images