Method for producing electrolyte membrane laminate, and electrolyte membrane laminate

Abstract

Provided are a method for producing an electrolyte membrane laminate and applications thereof, the method including: a step for preparing a plurality of transfer substrates each having a catalyst layer on a temporary support; a step for arranging the plurality of transfer substrates on an electrolyte membrane such that the electrolyte membrane and the catalyst layers are in contact with each other, in a state where at least some of the plurality of transfer substrates are in contact with each other; a step for thermocompression-bonding the electrolyte membrane and the plurality of transfer substrates; and a step for peeling off the temporary support.

Description

Manufacturing method of electrolyte membrane laminate and electrolyte membrane laminate

[0001] The present disclosure relates to a method for manufacturing an electrolyte membrane laminate and an electrolyte membrane laminate.

[0002] In recent years, the use of hydrogen has been attracting attention from the viewpoint of utilizing renewable energy, etc. One method for producing hydrogen is solid polymer water electrolysis. In solid polymer water electrolysis, a catalyst-coated membrane (CCM) has recently been used as a component constituting a water electrolysis device. The catalyst-coated membrane (CCM) has an electrode catalyst layer containing a water electrolysis catalyst and a solid electrolyte (e.g., an ionomer resin) formed on both sides of a solid polymer electron membrane (PEM), which is an ion exchange membrane.

[0003] For example, Japanese Patent Laid-Open Publication No. 2008-258175 discloses a transfer sheet for producing a catalyst layer-electrolyte membrane laminate, which is formed by applying a paste composition to a substrate and drying it to form a catalyst layer. Japanese Patent Laid-Open Publication No. 2007-123235 discloses a membrane-electrode assembly for a fuel cell, in which first regions 7a containing highly hydrophilic catalyst particles and second regions 7b containing less hydrophilic catalyst particles are formed in a checkerboard or striped pattern. International Publication No. 2011 / 111419 discloses a method for producing a membrane-electrode assembly comprising a catalyst layer and a solid polymer electrolyte membrane, the method comprising a preheating step of preheating a catalyst layer-supporting substrate formed by supporting a catalyst layer on one side of the transfer substrate and the solid polymer electrolyte membrane, a thermocompression bonding step of heating and pressurizing the catalyst layer-supporting substrate and the solid polymer electrolyte membrane to form an integrated bonding member, and a peeling step of peeling the transfer substrate from the bonding member.

[0004] As water electrolysis devices and fuel cells become larger, there is a demand for larger-area catalyst-coated membranes (electrolyte membrane laminates), and these large-area electrolyte membrane laminates are required to have uniform thickness.

[0005] The problem to be solved by one embodiment of the present disclosure has been made in view of the above circumstances, and is to provide an electrolyte membrane laminate that is larger in area and has excellent thickness uniformity compared to conventional ones, and a method for manufacturing the same.

[0006] The present disclosure includes the following aspects. <1> A method for manufacturing an electrolyte membrane laminate, comprising: preparing a plurality of transfer substrates each having a catalyst layer on a temporary support; arranging the plurality of transfer substrates on an electrolyte membrane in a state where at least a portion of the transfer substrates are in contact with one another so that the electrolyte membrane and the catalyst layer are in contact with one another; thermocompression-bonding the electrolyte membrane and the plurality of transfer substrates; and peeling off the temporary support. <2> A method for manufacturing an electrolyte membrane laminate according to <1>, in which all of the plurality of transfer substrates that are in contact with one another are thermocompression-bonded to the electrolyte membrane. <3> A method for manufacturing an electrolyte membrane laminate according to <1> or <2>, in which the thickness of the temporary support is 250 μm or less. <4> A method for manufacturing an electrolyte membrane laminate according to any one of <1> to <3>, in which, in the arranging step, the plurality of transfer substrates are arranged with overlapping portions where the transfer substrates overlap one another. <5> A method for manufacturing an electrolyte membrane laminate according to <4>, in which the width of the overlapping portion is more than 0 mm and not more than 5 mm. <6> A method for producing an electrolyte membrane laminate according to any one of <1> to <5>, further comprising a step of heating the transfer substrate and the electrolyte membrane before the thermocompression bonding step. <7> A method for producing an electrolyte membrane laminate according to any one of <1> to <6>, comprising the steps of arranging a plurality of transfer substrates on two main surfaces of the electrolyte membrane, thermocompression bonding, and peeling off the temporary support. <8> A method for producing an electrolyte membrane laminate according to any one of <1> to <7>, in which the catalyst layer of the transfer substrate has a solvent content of 1% by mass to 10% by mass. <9> A method for producing an electrolyte membrane laminate according to any one of <1> to <8>, in which the electrolyte membrane and the catalyst layer are thermocompression bonded after the peeling step. <10> An electrolyte membrane laminate comprising an electrolyte membrane and an electrode catalyst layer formed on the electrolyte membrane, in which a plurality of catalyst layers are bonded in the same plane. <11> An electrolyte membrane laminate according to <10>, having electrode catalyst layers on both sides of the electrolyte membrane.

[0007] According to one embodiment of the present disclosure, an electrolyte membrane laminate having a larger area and excellent thickness uniformity compared to conventional ones, and a method for manufacturing the same, are provided.

[0008] In the present disclosure, a numerical range indicated using "to" means a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In the present disclosure, the term "process" includes not only an independent process but also a process that cannot be clearly distinguished from other processes, as long as the intended purpose of the process is achieved. In the numerical ranges described in stages in the present disclosure, the upper or lower limit value described in a certain numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Furthermore, in the numerical ranges described in the present disclosure, the upper or lower limit value described in a certain numerical range may be replaced with a value shown in the examples. In the present disclosure, a combination of two or more preferred embodiments or aspects is a more preferred embodiment or aspect.

[0009] [Electrolyte Membrane Laminate] The method for manufacturing an electrolyte membrane laminate according to the present disclosure includes the steps of preparing a plurality of transfer substrates each having a catalyst layer on a temporary support (hereinafter also referred to as a "transfer substrate preparation step"), arranging the plurality of transfer substrates on the electrolyte membrane in a state in which at least a portion of the plurality of transfer substrates is in contact with one another so that the electrolyte membrane and the catalyst layer are in contact with each other (hereinafter also referred to as a "transfer substrate arrangement step"), thermocompression bonding the electrolyte membrane and the plurality of transfer substrates (hereinafter also referred to as a "thermocompression bonding step"), and peeling off the temporary support (hereinafter also referred to as a "temporary support peeling step").

[0010] Conventionally, when manufacturing a large-area electrolyte membrane laminate, a large amount of catalyst layer composition is applied to a large-area electrolyte membrane and then dried. However, this method requires large-scale application equipment and large-scale drying equipment, making it difficult to further increase the area. Furthermore, when attempting to form a membrane by applying a large amount of catalyst layer composition, the thickness tends to become uneven, making it difficult to form an electrode catalyst layer with a uniform thickness. In contrast, the manufacturing method of an electrolyte membrane laminate according to the present disclosure uses multiple transfer substrates having catalyst layers on temporary supports, and thermocompression bonds the electrolyte membrane to the multiple transfer substrates arranged in contact with each other, thereby producing a large-area (e.g., an area of ​​1000 mm x 1000 mm or more) electrolyte membrane laminate with excellent thickness uniformity.

[0011] JP 2008-258175 A discloses an embodiment in which multiple catalyst layers are arranged spaced apart from one another on an electrolyte membrane, but does not contemplate arranging multiple transfer substrates in contact with one another. JP 2007-123235 A describes arranging catalyst layers with different physical properties side by side, which is technically different from the method for manufacturing an electrolyte membrane laminate according to the present disclosure. WO 2011 / 111419 does not describe the arrangement of multiple transfer substrates.

[0012] <Transfer Substrate Preparation Step> The method for producing an electrolyte membrane laminate according to the present disclosure includes a step of preparing a plurality of transfer substrates each having a catalyst layer on a temporary support.

[0013] (Substrate for transfer) The material for transfer has a temporary support and a catalyst layer formed on the temporary support. The temporary support is not particularly limited as long as it is a substrate that can hold the catalyst layer and can be peeled off after the thermocompression bonding step.

[0014] Examples of the temporary support include polymer films such as polyimide, polyethylene terephthalate, polypalvanic acid aramid, polyamide (nylon), polysulfone, polyethersulfone, polyethersulfone, polyphenylene sulfide, polyetheretherketone, polyetherimide, polyacrylate, polyethylene naphthalate, etc. The temporary support may also be a film of a fluororesin such as an ethylene tetrafluoroethylene copolymer, a tetrafluoroethylene-hexafluoropropylene copolymer, a tetrafluoroperfluoroalkyl vinyl ether copolymer, or polytetrafluoroethylene (PTFE).

[0015] The thickness of the temporary support is not particularly limited, but is preferably 250 μm or less, more preferably 50 μm or less. The lower limit of the thickness is, for example, 30 μm.

[0016] The thickness of the temporary support is measured by the method described in JIS K 7130:1999.

[0017] The method for providing a catalyst layer on a temporary support is not particularly limited, and may be a method of laminating a temporary support and a sheet for a catalyst layer together, or a method of applying a catalyst-containing dispersion onto a temporary support and drying it.

[0018] From the viewpoint of productivity, the transfer substrate is preferably produced by applying a catalyst-containing dispersion onto a temporary support and drying the applied dispersion. The application method is not particularly limited, and any known application method can be used.

[0019] The plurality of transfer substrates are preferably produced by applying the same catalyst-containing dispersion onto a plurality of temporary supports and drying them. By using the same catalyst-containing dispersion onto a plurality of temporary supports, a large-area electrolyte membrane laminate can be produced without unevenness in the components.

[0020] Examples of the coating device include a bar coater, a screen printer, a doctor blade, a reverse coater, a die coater, a spray coater, a gravure coater, and a comma coater.

[0021] The catalyst-containing dispersion preferably contains a catalyst, a binder, and a solvent. The catalyst layer preferably contains a catalyst and a binder.

[0022] Examples of the catalyst include metals such as platinum, gold, ruthenium, iridium, rhodium, palladium, osmium, tungsten, lead, iron, chromium, cobalt, nickel, manganese, vanadium, molybdenum, gallium, and aluminum, and alloys thereof. From the viewpoints of catalytic activity and durability, the catalyst preferably contains platinum.

[0023] The catalyst is preferably supported on a carbon material, such as carbon black, activated carbon, coke, natural graphite, and artificial graphite, and more specifically, ketjen black, vulcan black, acetylene black, carbon fiber, single-walled carbon nanotubes, multi-walled carbon nanotubes, graphitized ketjen black, graphitized vulcan black, and graphitized acetylene black.

[0024] The binder is preferably a polymer having a proton-donating group. Examples of the binder include perfluorocarbon sulfonic acid polymers such as Nafion (registered trademark), poly(meth)acrylates having phosphoric acid groups in their side chains, heat-resistant aromatic polymers such as sulfonated polyether ether ketones, sulfonated polyether ketones, sulfonated polyether sulfones, sulfonated polysulfones, and sulfonated polybenzimidazoles; sulfonated polystyrenes, sulfonated polyoxetanes, sulfonated polyimides, sulfonated polyphenylene sulfides, sulfonated polyphenylene oxides, and sulfonated polyphenylenes.

[0025] Examples of solvents include water, methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, and tert-butanol.

[0026] The method for drying the catalyst-containing dispersion liquid after coating it on the temporary support is not particularly limited, and any known drying method can be used. The drying temperature is, for example, 25° C. to 130° C. The drying time is, for example, 1 minute to 1 hour.

[0027] The thickness of the catalyst layer is not particularly limited, but from the viewpoint of ensuring the amount of support, it is preferably 0.1 μm to 30 μm, and more preferably 1 μm to 20 μm.

[0028] The thickness of the catalyst layer is measured by the method described in JIS K 7130:1999.

[0029] The number of transfer substrates prepared in the transfer substrate preparation step is two or more, and is adjusted appropriately depending on the size of the electrolyte membrane laminate to be manufactured.

[0030] The shape of the transfer substrate prepared in the transfer substrate preparation step is not particularly limited, but is preferably rectangular (for example, oblong, square, etc.) When the transfer substrate is rectangular, the length of one side is preferably 10 cm to 230 cm from the viewpoint of coating suitability.

[0031] The content of the solvent in the catalyst layer of the transfer substrate is preferably 1% by mass to 10% by mass, and more preferably 2% by mass to 5% by mass. When the content of the solvent in the catalyst layer of the transfer substrate is within the above range, the adhesion between the catalyst layer and the electrolyte membrane is improved. When the transfer substrate is produced by applying a catalyst-containing dispersion onto a temporary support, the content of the solvent in the catalyst layer of the transfer substrate can be adjusted by changing the drying conditions.

[0032] The content of the solvent contained in the catalyst layer of the transfer substrate is measured using a method such as component identification using a combination of gas chromatography and a detector.

[0033] <Transfer substrate placement process> The method for manufacturing an electrolyte membrane laminate according to the present disclosure includes a process of placing a plurality of transfer substrates on an electrolyte membrane in a state in which at least a portion of the plurality of transfer substrates is in contact with one another so that the electrolyte membrane and the catalyst layer are in contact with each other.

[0034] Examples of the electrolyte membrane include a fluorine-based electrolyte membrane and a hydrocarbon-based electrolyte membrane. Specific examples of the electrolyte membrane include perfluorocarbon sulfonic acid polymers such as Nafion (registered trademark), poly(meth)acrylates having phosphoric acid groups in their side chains, heat-resistant aromatic polymers such as sulfonated polyether ether ketone, sulfonated polyether ketone, sulfonated polyether sulfone, sulfonated polysulfone, and sulfonated polybenzimidazole, sulfonated polystyrene, sulfonated polyoxetane, sulfonated polyimide, sulfonated polyphenylene sulfide, sulfonated polyphenylene oxide, and sulfonated polyphenylene.

[0035] The thickness of the electrolyte membrane is preferably 30 μm to 250 μm, and more preferably 50 μm to 200 μm, and is measured by the method described in JIS K 7130:1999.

[0036] In the transfer substrate placement step, multiple transfer substrates are placed on the electrolyte membrane in contact with each other. The transfer substrates are placed so that the catalyst layers of the transfer substrates are in contact with the electrolyte membrane. Furthermore, by placing multiple transfer substrates in contact with each other and then bonding the catalyst layers of the multiple transfer substrates in the subsequent thermocompression bonding step, an electrode catalyst layer with a larger area and better thickness uniformity than conventional electrode catalyst layers can be obtained. This allows the production of an electrolyte membrane laminate provided with a large-area electrode catalyst layer.

[0037] In the transfer substrate arrangement step, it is preferable to arrange the multiple transfer substrates with overlapping portions. By providing overlapping portions, a large-area electrode catalyst layer with excellent thickness uniformity can be more stably formed in the subsequent thermocompression bonding step. The width of the overlapping portion is preferably greater than 0 mm and not more than 5 mm. By setting the width of the overlapping portion to 5 mm or less, a large-area electrolyte membrane laminate with excellent thickness uniformity can be efficiently manufactured. The "width of the overlapping portion" refers to the shortest distance between one end and the other end of the two transfer substrates in the overlapping portion where the two transfer substrates overlap.

[0038] <Thermocompression Bonding Step> The method for manufacturing an electrolyte membrane laminate according to the present disclosure includes a step of thermocompression bonding an electrolyte membrane and a plurality of transfer substrates.

[0039] The thermocompression bonding step can be performed using a known thermocompression bonding device, for example, by pressing a heating member against the film, sandwiching the film between heating members, etc. Examples of the heating member include a hot plate, a hot block, and a hot roll. A laminator equipped with a pair of hot rolls may be used, and thermocompression bonding may be performed by passing the film between the pair of rolls.

[0040] The temperature for thermocompression bonding is preferably 80° C. to 200° C., more preferably 130° C. to 180° C. The pressure for thermocompression bonding is preferably 0.1 MPa to 5 MPa, more preferably 0.5 MPa to 3 MPa.

[0041] In the thermocompression bonding step, it is preferable to thermocompress all of the plurality of transfer substrates to the electrolyte membrane at the same time. As a method for thermocompression bonding at the same time, for example, a method for thermocompression bonding at the same time using a thermocompression bonding device can be mentioned. By thermocompression bonding a plurality of transfer substrates at the same time, a large-area electrolyte membrane laminate with excellent thickness uniformity can be efficiently produced.

[0042] The method for manufacturing an electrolyte membrane laminate according to the present disclosure includes a step of peeling off the temporary support from an assembly of an electrolyte membrane and multiple transfer substrates. By peeling off and removing the temporary support, multiple catalyst layers are transferred onto the electrolyte membrane, and an electrode catalyst layer composed of the multiple catalyst layers can be formed on the electrolyte membrane.

[0043] The method for peeling off the temporary support is not particularly limited, and can be carried out by a commonly known method.

[0044] The method for producing an electrolyte membrane laminate according to the present disclosure may include steps other than the transfer substrate preparation step, the transfer substrate arrangement step, the thermocompression bonding step, and the temporary support peeling step.

[0045] A step of heating the transfer substrate and the electrolyte membrane may be performed before the thermocompression bonding step. By heating the transfer substrate and the electrolyte membrane, the catalyst layer included in the transfer substrate softens, improving adhesion to the electrolyte membrane. The heating means for the transfer substrate and the electrolyte membrane is not particularly limited, and known heating means can be used. The heating temperature for the transfer substrate is, for example, 50°C to 200°C. The heating temperature for the electrolyte membrane is, for example, 50°C to 150°C.

[0046] Furthermore, when the transfer substrates are arranged with overlapping portions in the transfer substrate arrangement step, the method for manufacturing an electrolyte membrane laminate according to the present disclosure preferably includes a step of removing the overlapping portions after the thermocompression bonding step. Examples of methods for removing the overlapping portions include a method of applying an adhesive roll to the overlapping portions and pulling them.

[0047] Furthermore, it is preferable to peel off the temporary support after the thermocompression bonding step, and then further thermocompression bond the electrolyte membrane and catalyst layer again. By providing a thermocompression bonding step after peeling off the temporary support, it is possible to form a large-area electrode catalyst layer with excellent thickness uniformity.

[0048] The number of times thermocompression bonding is performed after the first thermocompression bonding step is, for example, 1 to 5. The thermocompression bonding conditions of the second and subsequent thermocompression bonding steps may be the same as or different from the thermocompression bonding conditions of the first thermocompression bonding step.

[0049] Furthermore, in the method for producing an electrolyte membrane laminate according to the present disclosure, it is preferable to perform a transfer substrate placement step, a thermocompression bonding step, and a temporary support peeling step on the two main surfaces of the electrolyte membrane.

[0050] The two main surfaces of the electrolyte membrane refer to two opposing surfaces that are larger in area than the other surfaces.

[0051] The transfer substrate placement step, thermocompression bonding step, and temporary support peeling step for one of the two main surfaces of the electrolyte membrane may be the same as or different from the transfer substrate placement step, thermocompression bonding step, and temporary support peeling step for the other of the two main surfaces of the electrolyte membrane.

[0052] The preferred embodiments of the transfer substrate placement step, the thermocompression bonding step, and the temporary support peeling step are as described above.

[0053] [Electrolyte Membrane Stack] The electrolyte membrane stack according to the present disclosure includes an electrolyte membrane and an electrode catalyst layer formed on the electrolyte membrane and including a plurality of catalyst layers bonded together in the same plane.

[0054] The preferred embodiments of the electrolyte membrane and catalyst layer are as described above. The electrode catalyst layer is a layer in which a plurality of catalyst layers are bonded together in the same plane.

[0055] The phrase "a plurality of catalyst layers are joined in the same plane" means that the plurality of catalyst layers are connected to each other on a certain plane.

[0056] The electrolyte membrane laminate according to the present disclosure has a bonding catalyst layer, which differs from the conventional configuration in which a single catalyst layer is formed on an electrolyte membrane. The electrolyte membrane laminate according to the present disclosure has the same appearance as the conventional configuration, but by observing the surface of the bonding catalyst layer with a scanning electron microscope (SEM), for example, it is possible to confirm that the multiple catalyst layers are bonded in the same plane.

[0057] The electrolyte membrane laminate according to the present disclosure preferably has bonding catalyst layers on both sides of the electrolyte membrane.

[0058] The present invention will be explained in more detail below with reference to examples. The materials, amounts used, ratios, details of each step, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below. Note that "parts" are all based on mass.

[0059] Example 1 Transfer Substrate Preparation Step 72 g of a platinum-carbon black-supported catalyst (product name "TEC10E50", manufactured by Tanaka Kikinzoku Kogyo Kogyo) and 476 g of IPA (isopropanol) were stirred and mixed in a disperser to prepare a platinum-carbon black-supported catalyst dispersion. 210 g of a 20 mass % polymer dispersion (product name "Nafion (registered trademark) D-2020, manufactured by Chemours) was added to the dispersion, and the mixture was stirred and mixed in a disperser to obtain a catalyst layer dispersion.

[0060] The catalyst layer dispersion was applied to a PTFE film (product name "Nitoflon No. 900 UL", manufactured by Nitto Denko Corporation, thickness 50 μm, 40 cm × 120 cm) as a temporary support, and dried at 90°C for 10 minutes. This resulted in a transfer substrate having a catalyst layer of 200 μm thickness formed on the temporary support. The content of solvent in the catalyst layer of the transfer substrate was 1 mass%.

[0061] <Transfer substrate placement step> Three transfer substrates (40 cm x 120 cm) were arranged on an electrolyte membrane (product name "Nafion (registered trademark) N115", manufactured by DuPont, 127 μm thick, 120 cm square) so that the electrolyte membrane and the catalyst layer were in contact with each other. The width and length of the overlapping portion between the transfer substrates was 1 mm.

[0062] <Preheating Step> Using a hot plate heated by a heater, the electrolyte membrane and the transfer substrate were preheated at a temperature of 100° C. for 3 minutes.

[0063] <Thermocompression bonding step> Using a thermal laminator, the electrolyte membrane and the three overlapping transfer substrates were thermocompression bonded to each other at a temperature of 135° C. and a press pressure of 1 MPa to form a laminate.

[0064] <Temporary support peeling step> Using an adhesive roll, the temporary support and the overlapping portion between the transfer substrates were peeled off from the laminate, and the catalyst layer was transferred onto the electrolyte membrane to form an electrode catalyst layer. In this way, an electrolyte membrane laminate was obtained.

[0065] Example 2 An electrolyte membrane laminate was obtained in the same manner as in Example 1, except that the thickness of the temporary support was changed to 250 μm.

[0066] [Example 3] A transfer substrate was obtained in the same manner as in Example 1, except that the catalyst layer dispersion was applied to a temporary support and dried, followed by vacuum drying at 90°C for 1 hour. The content of the solvent in the catalyst layer of the transfer substrate was 0.1 mass%. An electrolyte membrane laminate was then obtained in the same manner as in Example 1, except that the above transfer substrate was used.

[0067] [Example 4] A transfer substrate was obtained in the same manner as in Example 1, except that the catalyst layer dispersion was applied to a temporary support and dried at 90°C for 15 seconds. The content of the solvent in the catalyst layer of the transfer substrate was 8 mass%. Then, an electrolyte membrane laminate was obtained in the same manner as in Example 1, except that the above transfer substrate was used.

[0068] Example 5 An electrolyte membrane laminate was obtained in the same manner as in Example 1, except that the thickness of the temporary support was changed to 300 μm.

[0069] [Example 6] A transfer substrate was obtained in the same manner as in Example 1, except that the catalyst layer dispersion was applied to a temporary support and dried, followed by vacuum drying at 90°C for 60 minutes. The content of the solvent in the catalyst layer of the transfer substrate was 15 mass%. An electrolyte membrane laminate was then obtained in the same manner as in Example 1, except that the above transfer substrate was used.

[0070] Example 7 An electrolyte membrane laminate was obtained in the same manner as in Example 1, except that the preheating step was not carried out.

[0071] [Comparative Example 1] An electrolyte membrane laminate was obtained in the same manner as in Example 1, except for the following points. In the transfer substrate preparation step, the size of the temporary support was set to 120 cm square, and a 120 cm square catalyst layer was formed to obtain a transfer substrate. In the transfer substrate placement step, one 120 cm square transfer substrate was placed on the electrolyte membrane.

[0072] <<Evaluation>> - Thickness Uniformity - The thickness of the obtained electrolyte membrane laminate was measured by observing the cross section using a scanning electron microscope (SEM). Specifically, six sections were cut out at 20 cm intervals in the width direction (120 cm width), frozen in liquid nitrogen, and cross sections were obtained using a razor blade. The difference (μm) between the maximum and minimum thickness values ​​in the width direction was calculated. The smaller the difference between the maximum and minimum thickness values, the better the thickness uniformity.

[0073] - Appearance - The appearance of the obtained electrolyte membrane laminate was visually observed and evaluated. The evaluation criteria are as follows: A: Good. B: Slightly poor appearance, but no practical problem. C: Poor appearance, practical problem.

[0074] - Adhesion - For the obtained electrolyte membrane laminate, an adhesion test (cross-cut method) was performed in accordance with JIS K5600 to confirm the adhesion between the catalyst layer and the electrolyte membrane. The evaluation criteria are as follows: A: No peeling occurred. B: Peeling occurred.

[0075]

[0076] As shown in Table 1, Examples 1 to 7 include the steps of preparing a plurality of transfer substrates each having a catalyst layer on a temporary support, arranging the plurality of transfer substrates on the electrolyte membrane in a state in which at least a portion of the plurality of transfer substrates is in contact with one another so that the electrolyte membrane and the catalyst layer are in contact, thermocompression bonding the electrolyte membrane and the plurality of transfer substrates, and peeling off the temporary support, and an electrolyte membrane laminate having a larger area and excellent thickness uniformity compared to conventional examples was obtained.

[0077] The disclosure of Japanese Patent Application No. 2024-013639, filed on January 31, 2024, is incorporated herein by reference in its entirety. In addition, all documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually indicated to be incorporated by reference.

Claims

1. A method for manufacturing an electrolyte membrane laminate, comprising: a step of preparing a plurality of transfer substrates each having a catalyst layer on a temporary support; a step of arranging the plurality of transfer substrates on an electrolyte membrane in a state in which the electrolyte membrane and the catalyst layer are in contact with each other and at least a portion of the plurality of transfer substrates is in contact with each other; a step of thermocompression bonding the electrolyte membrane and the plurality of transfer substrates; and a step of peeling off the temporary support.

2. The method for producing an electrolyte membrane laminate according to claim 1, wherein all of the plurality of transfer substrates in contact with each other are thermocompression bonded to the electrolyte membrane.

3. The method for producing an electrolyte membrane laminate according to claim 1 or 2, wherein the thickness of the temporary support is 250 μm or less.

4. A method for manufacturing an electrolyte membrane laminate according to claim 1 or claim 2, wherein in the arranging step, the plurality of transfer substrates are arranged with overlapping portions where the transfer substrates overlap each other.

5. The method for producing an electrolyte membrane laminate according to claim 4, wherein the width of the overlapping portion is greater than 0 mm and not greater than 5 mm.

6. The method for producing an electrolyte membrane laminate according to claim 1 or 2, further comprising a step of heating the transfer substrate and the electrolyte membrane before the thermocompression bonding step.

7. A method for manufacturing an electrolyte membrane laminate according to claim 1 or claim 2, comprising the steps of placing the plurality of transfer substrates on the two main surfaces of the electrolyte membrane, thermocompression bonding, and peeling off the temporary support.

8. The method for producing an electrolyte membrane laminate according to claim 1 or 2, wherein the content of the solvent in the catalyst layer of the transfer substrate is 1% by mass to 10% by mass.

9. The method for producing an electrolyte membrane laminate according to claim 1 or 2, further comprising thermocompression bonding the electrolyte membrane and the catalyst layer after the peeling step.

10. An electrolyte membrane laminate comprising: an electrolyte membrane; and an electrode catalyst layer formed on the electrolyte membrane, the electrode catalyst layer comprising a plurality of catalyst layers bonded together in the same plane.

11. The electrolyte membrane laminate according to claim 10, wherein the electrode catalyst layer is provided on both sides of the electrolyte membrane.

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