Fuel cell assembly and method of manufacturing same

Abstract

This fuel cell assembly (10) comprises: an electrode member (2) that has a membrane electrode assembly (20) having an electrolyte membrane and an electrode catalyst layer, and gas diffusion layers (21, 22); a gasket (30) made of solid rubber disposed in a frame form on the outside of the electrode member (2) in the surface direction; and an adhesive member (40) that has a thermoplastic polymer, is disposed in frame form on the outside of the electrode member (2) in the surface direction, and adheres the electrode member (2) and the gasket (30) to integrate the electrode member (2) and the gasket (30). The form of adhesion of the adhesive member (40) with respect to the electrode member (2) is at least one of impregnation to the gas diffusion layers (21, 22) and adhesion to the membrane electrode assembly (20). The adhesive member (40) covers at least the outer peripheral end face of the electrolyte membrane. The thickness of the adhesive member (40) is the same or greater than the thickness of the gas diffusion layer (21) disposed on one side of the membrane electrode assembly (20), and at least a portion of one side of the adhesive member (40) in the thickness direction is covered by the gasket (30).

Description

[Technical Field]

[0001] The present disclosure relates to a fuel cell assembly in which an electrode member and a gasket are integrated with an adhesive member, and a method for manufacturing the same. [Background technology]

[0002] Fuel cells have a stack structure in which many cells are stacked. The stack of cells is fastened together by end plates arranged on both sides in the stacking direction. For example, a cell of a polymer electrolyte fuel cell has electrode members each having a membrane electrode assembly (MEA) and a gas diffusion layer, separators stacked on the electrode members, and rubber gaskets arranged around the electrode members to seal the electrode members from reactant gases and refrigerants.

[0003] Silicone rubber is often used as a gasket material (see, for example, Patent Documents 1 to 3). Because silicone rubber is liquid before hardening, it is easy to mold using injection molding or other methods, and it hardens at a relatively low temperature. Furthermore, when liquid silicone rubber is injection molded, a portion of the material is impregnated into the gas diffusion layer of the electrode member, thereby improving sealing performance. However, silicone rubber is susceptible to hydrolysis of siloxane bonds (Si-O-Si bonds) in the operating environment of a fuel cell, raising concerns about reduced sealing performance. Furthermore, decomposition products produced by the hydrolysis of silicone rubber may contaminate and deteriorate the electrolyte membrane and electrode catalyst layer that constitute the MEA.

[0004] For this reason, alternative gasket materials to silicone rubber are being investigated, such as ethylene-propylene-diene rubber (EPDM) and fluororubber, which offer excellent durability, high-temperature properties, and low gas permeability. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] U.S. Patent No. 7,070,876 [Patent Document 2] U.S. Patent No. 6,716,550 [Patent Document 3] Japanese Patent Application Laid-Open No. 2013-168353 [Patent Document 4] Japanese Patent Application Laid-Open No. 2007-66766 Summary of the Invention [Problem to be solved by the invention]

[0006] However, because EPDM and fluororubber are solid before curing, they lack the fluidity of silicone rubber. Furthermore, polymer membranes such as perfluorinated sulfonic acid membranes are used for the electrolyte membranes of polymer electrolyte fuel cells. Therefore, when placing gasket materials near the electrolyte membrane for curing, care must be taken to prevent the electrolyte membrane from deteriorating due to heat during curing and to prevent damage to the gas diffusion layer due to molding stresses such as injection pressure. However, it is difficult to cure EPDM and fluororubber in a practically short time at temperatures that take into account the heat resistance of the electrolyte membrane. Thus, when using solid rubbers such as EPDM and fluororubber, it is difficult to integrally mold the gasket into the electrode component by injection molding at relatively low temperatures.

[0007] For example, Patent Document 2 describes a membrane electrode sealing assembly including an MEA, a framing seal, and an integrated seal. The framing seal is formed as a separate member from silicone, EPDM, or the like, and is arranged to sandwich the end of the MEA in the thickness direction. The integrated seal is formed from a liquid sealant material such as a thermoplastic resin or a liquid elastomer such as silicone, and is impregnated into the fluid distribution layer (gas diffusion layer) of the MEA. The framing seal and the integrated seal are not bonded together.

[0008] Patent Document 3 describes a fuel cell comprising an electrode member having an MEA and a gas diffusion layer, a resin frame member arranged on the outer periphery of the electrode member, a separator, and a sealing member (gasket). The resin frame member is made of polyphenylene sulfide (PPS) or the like, and is bonded to the MEA via an adhesive layer and to the gas diffusion layer via a resin-impregnated portion. The sealing member is made of silicone rubber, EPDM, or the like, and is integrated with the separator and is not bonded to the resin frame member.

[0009] Patent Document 4 describes an assembly comprising an electrode member having an MEA and a gas diffusion layer, and a gasket structure arranged on the outer periphery of the electrode member. Gas diffusion layers of different areas are arranged on both sides of an electrolyte membrane. The gasket structure is made of polyethylene naphthalate (PEN), polyethylene terephthalate (PET), or the like. The gasket structure is adhered via an adhesive layer to the surface of the electrolyte membrane exposed on the side with the smaller area of ​​the gas diffusion layer and to the outer peripheral edge face of the gas diffusion layer. The adhesive layer is made of a hot-melt adhesive such as polyolefin. The thickness of the adhesive layer is smaller than that of the gas diffusion layer, and it does not contact the outer peripheral edge face of the electrolyte membrane.

[0010] Patent Documents 2 and 3 list silicone rubber, EPDM, and other materials as gasket materials, but do not mention any consideration of the deterioration of sealing performance when using silicone rubber or contamination of the MEA by decomposition products. Furthermore, the structures described in Patent Documents 2 and 3 do not integrate the gasket and electrode member via an adhesive. In the assembly described in Patent Document 4, the gasket and electrolyte membrane are bonded via an adhesive layer. However, the adhesive layer does not cover the outer peripheral end surface of the electrolyte membrane, and its thickness is smaller than that of the gas diffusion layer. Furthermore, the gas diffusion layer is not impregnated. As a result, the adhesive has a weak holding force against the electrode member, which can lead to damage during handling or external inputs such as vibration during stacking.

[0011] The present disclosure has been made in consideration of the above-described circumstances, and aims to provide a fuel cell assembly in which a solid rubber gasket and an electrode member are integrated, and which has excellent sealing properties, durability, and productivity, as well as a method for manufacturing the same. [Means for solving the problem]

[0012] (1) In order to solve the above-mentioned problems, the present disclosure provides a fuel cell assembly comprising: an electrode member having a membrane electrode assembly having an electrolyte membrane and an electrode catalyst layer; and a gas diffusion layer disposed on at least one of both surfaces of the membrane electrode assembly in a thickness direction; a solid rubber gasket disposed in a frame shape on the outer side of the electrode member in the plane direction, with a plane direction being a direction intersecting the stacking direction of the electrode members; and an adhesive member having a thermoplastic polymer, disposed in a frame shape on the outer side of the electrode member in the plane direction, and adhered to the electrode member and the gasket to integrate the electrode member and the gasket; the adhesive member is adhered to the electrode member by at least one of impregnation into the gas diffusion layer and adhesion to the membrane electrode assembly; the adhesive member covers at least the outer peripheral end face of the electrolyte membrane; the thickness of the adhesive member in the stacking direction of the electrode members is equal to or greater than the thickness of the gas diffusion layer disposed on that one surface of the membrane electrode assembly; and at least a portion of one surface of the adhesive member in the thickness direction is covered by the gasket.

[0013] (2) A manufacturing method of a fuel cell assembly of the present disclosure, as a first example of a manufacturing method of a fuel cell assembly having the configuration described in (1) above, is characterized by comprising: a gasket molding step of molding a gasket from solid rubber; an arrangement step of arranging an electrode member having a membrane electrode assembly having an electrolyte membrane and an electrode catalyst layer and a gas diffusion layer disposed on at least one of both surfaces in the thickness direction of the membrane electrode assembly, the molded gasket, and an adhesive member having a thermoplastic polymer; and an integration step of melting and curing the adhesive member to integrate the electrode member and the gasket with the adhesive member.

[0014] (3) A manufacturing method of a fuel cell assembly of the present disclosure, as a second example of the manufacturing method of the fuel cell assembly having the configuration described in (1) above, is characterized by comprising: a gasket molding step of molding a gasket from solid rubber; an arrangement step of arranging the molded gasket and an electrode member having a membrane electrode assembly having an electrolyte membrane and an electrode catalyst layer and a gas diffusion layer disposed on at least one of both surfaces in the thickness direction of the membrane electrode assembly; and an integration step of injecting a liquid composition containing a thermoplastic polymer into the mold and curing it, thereby integrating the electrode member and the gasket with an adhesive member that is a cured product of the liquid composition.

[0015] (4) The fuel cell assembly having the configuration described in (1) above may further include a separator laminated on the electrode member and the gasket, and the adhesive member may be bonded to the electrode member, the gasket, and the separator to integrate the electrode member, the gasket, and the separator.

[0016] (5) A manufacturing method of a fuel cell assembly of the present disclosure, as a first example of a manufacturing method of a fuel cell assembly including a separator having the configuration described in (4) above, is characterized by comprising: a gasket molding step of molding a gasket from solid rubber; an arrangement step of arranging, on one side of a separator, an electrode member having a membrane electrode assembly having an electrolyte membrane and an electrode catalyst layer and a gas diffusion layer disposed on at least one of both surfaces in the thickness direction of the membrane electrode assembly, the molded gasket, and an adhesive member having a thermoplastic polymer; and an integration step of melting and curing the adhesive member to integrate the electrode member, the gasket, and the separator with the adhesive member.

[0017] (6) A manufacturing method of a fuel cell assembly according to the present disclosure, as a second example of a manufacturing method of a fuel cell assembly including a separator having the configuration described in (4) above, is characterized by comprising: a gasket molding step of molding a gasket from solid rubber; an arrangement step of arranging a separator in a molding die and, on one side of the separator, arranging the molded gasket and an electrode member having a membrane electrode assembly having an electrolyte membrane and an electrode catalyst layer and a gas diffusion layer disposed on at least one of both surfaces in the thickness direction of the membrane electrode assembly; and an integration step of injecting a liquid composition containing a thermoplastic polymer into the molding die and curing it to integrate the electrode member, the gasket, and the separator with an adhesive member that is a cured product of the liquid composition. [Effects of the Invention]

[0018] (1) In the fuel cell assembly disclosed herein, the gasket is made of solid rubber rather than liquid rubber. Because liquid silicone rubber is not used, problems such as reduced sealing performance due to hydrolysis of siloxane bonds and MEA contamination due to decomposition products can be eliminated. The gasket is adhered to the electrode member with an adhesive. This eliminates the need to impregnate the gas diffusion layer of the electrode member with the gasket to improve adhesion and sealing performance. Because there is less contact between the gasket and the electrode member, there are fewer concerns about reduced sealing performance or MEA contamination due to the gasket material. This allows for greater freedom in selecting gasket materials.

[0019] In the fuel cell assembly of the present disclosure, the adhesive member is attached to the electrode member by at least one of impregnation into the gas diffusion layer and adhesion to the membrane electrode assembly (hereinafter also referred to as "MEA" in this disclosure). This achieves high adhesion and sealing properties. Furthermore, the adhesive member covers at least the outer peripheral end surface of the electrolyte membrane, protecting and reinforcing the electrolyte membrane, suppressing deformation, and improving sealing properties. In the stacking direction of the electrode members, the thickness of the adhesive member is equal to or greater than the thickness of the gas diffusion layer disposed on one side of the membrane electrode assembly. This ensures the strength and adhesion of the adhesive member. Additionally, deformation of the electrolyte membrane can be suppressed, improving durability and ease of handling. At least a portion of one surface of the adhesive member in the thickness direction is covered with a gasket. This improves sealing properties when fuel cell assemblies are stacked to form a fuel cell. Furthermore, tackiness of the adhesive member between adjacent cells is suppressed, making it less likely for the adhesive member to leave marks on stacked components. Furthermore, if some of the cells need to be repaired or replaced, they can be easily removed, improving repairability.

[0020] (2) According to a first manufacturing method for a fuel cell assembly of the present disclosure (hereinafter referred to as the "first manufacturing method of the present disclosure"), which is a first example of a manufacturing method for a fuel cell assembly having the configuration described in (1) above, a gasket is manufactured from solid rubber in advance in the gasket molding step. By separating the gasket manufacturing step from the step of integrating the electrode member, the gasket can be manufactured using solid rubber, which has lower fluidity than a liquid material. The curing temperature of the solid rubber can be set regardless of the heat resistance temperature of the electrolyte membrane. This allows the gasket to be manufactured at a high temperature in a short time. Therefore, according to the first manufacturing method of the present disclosure, a highly durable gasket can be manufactured with high productivity. Furthermore, in the integration step, an adhesive member having a thermoplastic polymer is melted and cured to bond the electrode member and the gasket. As a result, when the adhesive member is arranged so as to contact the gas diffusion layer of the electrode member, the adhesive member can be impregnated into the gas diffusion layer, thereby achieving stronger adhesion and better sealing properties.

[0021] (3) In a second manufacturing method for a fuel cell assembly of the present disclosure (hereinafter referred to as "the second manufacturing method of the present disclosure"), which is a second example of a manufacturing method for a fuel cell assembly having the configuration described in (1) above, an electrode member and a gasket are placed in a mold, and a liquid composition containing a thermoplastic polymer is injected and cured, thereby integrating the electrode member and the gasket with an adhesive member that is the cured product of the liquid composition. In addition to the effects achieved by the first manufacturing method described above, the second manufacturing method of the present disclosure improves the efficiency of manufacturing fuel cell assemblies, thereby further increasing productivity.

[0022] (4) In a fuel cell assembly according to the present disclosure that includes a separator, if the main components of the cell, including the separator, are integrated with an adhesive member, the fuel cell assemblies become easier to handle when stacked, simplifying the stacking process. Also, misalignment of components during stacking is less likely to occur. This improves workability and productivity. Furthermore, the adhesive member and the separator are bonded together, improving sealing performance.

[0023] (5) According to the third manufacturing method of the fuel cell assembly of the present disclosure (hereinafter referred to as the “third manufacturing method of the present disclosure”), which is a first example of a manufacturing method of a fuel cell assembly having a separator of the configuration described in (4) above, an electrode member, a gasket, and an adhesive member are arranged on one side of the separator, and the adhesive member is melted and hardened, thereby making it possible to easily integrate the electrode member, the gasket, and the separator in addition to the effects achieved by the first manufacturing method described in (2) above.

[0024] (6) According to the fourth manufacturing method of the fuel cell assembly of the present disclosure (hereinafter referred to as the “fourth manufacturing method of the present disclosure”), which is a second example of a manufacturing method of a fuel cell assembly including a separator having the configuration described in (4) above, an electrode member and a gasket are placed on one side of the separator, and a liquid composition containing a thermoplastic polymer is injected and hardened. In addition to the effects achieved by the second manufacturing method described in (3) above, the electrode member, gasket, and separator can be easily integrated. [Brief explanation of the drawings]

[0025] [Figure 1] FIG. 2 is a top view of the fuel cell assembly of the first embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II of FIG. [Figure 3] FIG. 2 is a cross-sectional view of a molding die used in molding a gasket. [Figure 4] FIG. 2 is a schematic cross-sectional view of a separator coated with an adhesive member. [Figure 5]5A to 5C are cross-sectional schematic views of each member in an arrangement step. [Figure 6] 5A to 5C are cross-sectional schematic views of each member in an integration step. [Figure 7] FIG. 10 is a cross-sectional view schematically illustrating a gasket to which an adhesive member is adhered in an adhesive member fixing step in a manufacturing method for a fuel cell assembly according to a second embodiment. [Figure 8] 3A to 3C are cross-sectional schematic views of components in an arrangement step of the manufacturing method. [Figure 9] FIG. 10 is a partial cross-sectional view of a fuel cell assembly according to a third embodiment. [Figure 10] 10A and 10B are cross-sectional schematic views of components in an arrangement step of a manufacturing method for a fuel cell assembly according to a third embodiment. [Figure 11] FIG. 2 is a cross-sectional view of a molding die in an integration step of the same manufacturing method. [Figure 12] FIG. 10 is a partial cross-sectional view of a fuel cell assembly according to a fourth embodiment. [Figure 13] 10 is a partial cross-sectional view of a fuel cell assembly according to a fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0026] First Embodiment [Configuration of fuel cell assembly] First, the configuration of the fuel cell assembly of this embodiment will be described. Fig. 1 shows a top view of the fuel cell assembly of this embodiment. Fig. 2 shows a cross-sectional view taken along line II-II of Fig. 1. In the orientation of the figure, the front-rear and left-right directions indicate the surface directions of each member, and the up-down direction indicates the thickness direction and stacking direction of each member. In Fig. 1, for ease of explanation, stacked members are shown transparently, and adhesive members are shown hatched. As shown in Figs. 1 and 2, the fuel cell assembly 10 includes an electrode member 2, a gasket 30, an adhesive member 40, and a separator 50.

[0027] The separator 50 is a bipolar plate made of carbon and has a thin rectangular plate shape. The electrode member 2, gasket 30, and adhesive member 40 are disposed on the upper surface of the separator 50. In the areas of the upper and lower surfaces of the separator 50 that overlap with the electrode member 2, uneven flow paths are formed.

[0028] The electrode member 2 has a rectangular thin film shape. The electrode member 2 comprises an MEA 20 and a pair of upper and lower gas diffusion layers 21 and 22 disposed on both sides of the MEA 20 in the thickness direction. The MEA 20, upper and lower gas diffusion layers 21 and 22 have the same surface area. The MEA 20 comprises an electrolyte membrane and a pair of electrode catalyst layers disposed on both sides of the electrolyte membrane in the thickness direction. The electrolyte membrane is a perfluorinated sulfonic acid membrane, and the electrode catalyst layer contains carbon particles carrying a platinum-containing catalyst. The upper and lower gas diffusion layers 21 and 22 have the same configuration and each contain carbon paper. The upper gas diffusion layer 21 has an upper impregnated portion 210 impregnated with an adhesive member 40. The upper impregnated portion 210 is disposed at the outer peripheral edge of the upper gas diffusion layer 21. Similarly, the lower gas diffusion layer 22 has a lower impregnated portion 220 impregnated with an adhesive member 40. The lower impregnation portion 220 is disposed at the outer peripheral edge of the lower gas diffusion layer 22 .

[0029] The gasket 30 has a frame shape when viewed from above and is disposed on the outside of the electrode member 2. The gasket 30 is made of a cross-linked product of a rubber composition containing EPDM. The gasket 30 has a main body portion 300 and an overlapping portion 301. The main body portion 300 is disposed on the outside of the frame and has two lip portions 302 protruding in the thickness direction. The tops of the two lip portions 302 are curved. The overlapping portion 301 is disposed on the inside of the frame and extends from the main body portion 300 so as to cover the upper surface of the adhesive member 40 and the outer edge of the upper surface of the electrode member 2 (areas corresponding to the upper impregnated portion 210 and the lower impregnated portion 220). When a fuel cell is constructed, the gasket 30 elastically contacts the separator of another fuel cell assembly to be stacked thereon.

[0030] The adhesive member 40 has a frame shape when viewed from above and is disposed on the outer side of the electrode member 2. The adhesive member 40 is disposed between the electrode member 2 and the gasket 30 in the planar direction. The thickness T2 of the adhesive member 40 is the same as that of the electrode member 2 and is greater than the thicknesses T1 of the upper gas diffusion layer 21 and the lower gas diffusion layer 22. The upper surface of the adhesive member 40 is covered by the overlapping portion 301 of the gasket 30. The total thickness T3 of the overlapping portion 301 of the gasket 30 and the adhesive member 40 is greater than the thickness of the electrode member 2. The adhesive member 40 contains an olefin-based thermoplastic resin modified with acid (hereinafter referred to as "acid-modified olefin-based thermoplastic resin" as appropriate). The melting point of the acid-modified olefin-based thermoplastic resin is approximately 130°C. The acid-modified olefin-based thermoplastic resin has adhesive properties. As described above, a portion of the adhesive member 40 is impregnated into the upper impregnated portion 210 of the upper gas diffusion layer 21 and the lower impregnated portion 220 of the lower gas diffusion layer 22. In addition, the adhesive member 40 is adhered to the components with which it is in contact, specifically, the outer peripheral end surface of the MEA 20 including the electrolyte membrane, the gasket 30, and the separator 50. In this way, the electrode member 2, the gasket 30, and the separator 50 are integrated by the adhesive member 40.

[0031] [Method of manufacturing fuel cell assembly] Next, a method for manufacturing the fuel cell assembly of this embodiment will be described. The method for manufacturing the fuel cell assembly of this embodiment includes a gasket molding step, a placement step, and an integration step.

[0032] (1) Gasket molding process In this process, a rubber composition containing EPDM is injection molded to form gasket 30. FIG. 3 shows a cross-sectional schematic diagram of the mold used in molding the gasket. Note that all of the following drawings, including FIG. 3, correspond to FIG. 2 and show a portion corresponding to the II-II cross section of FIG. 1. As shown in FIG. 3, mold 8 includes upper mold 80 and lower mold 81. By combining upper mold 80 and lower mold 81, a cavity 82 having a shape symmetrical to that of gasket 30 is defined. First, mold 8 is clamped, and a rubber composition preheated to approximately 100°C is injected into cavity 82. The rubber composition is held at 170°C for 10 minutes to crosslink the rubber composition, and then mold 8 is opened and gasket 30 is removed.

[0033] (2) Placement process In this step, the electrode member 2, the formed gasket 30, and the adhesive member 40 are arranged on the upper surface of the separator 50. FIG. 4 shows a cross-sectional view of the separator to which the adhesive member has been applied. FIG. 5 shows a cross-sectional view of each member in the arrangement step. First, as shown in FIG. 4, the adhesive member 40, which has been heated to a temperature of 150°C or higher so as to have sufficient fluidity, is applied in a frame shape to a predetermined position on the upper surface of the separator 50 using a dispenser. Next, as shown in FIG. 5, the electrode member 2 is arranged inside the adhesive member 40 on the upper surface of the separator 50, and the gasket 30 is arranged outside the adhesive member 40.

[0034] (3) Integration process In this step, the adhesive member 40 is melted and then hardened to integrate the electrode member 2, gasket 30, and separator 50. FIG. 6 shows a cross-sectional view of each component in the integration step. The stack of the separator 50, electrode member 2, gasket 30, and adhesive member 40 set in the previous arrangement step is placed in a hot press, and the adhesive member 40 is pressed by a pressing member 83 heated to 140°C, as indicated by the downward white arrow in FIG. 6. This melts the adhesive member 40, and as indicated by the horizontal white arrow in FIG. 6, it impregnates the outer peripheral ends of the upper gas diffusion layer 21 and the lower gas diffusion layer 22 and bonds them to the outer peripheral end face of the MEA 20, the gasket 30, and the separator 50. Thereafter, the laminate is returned to room temperature, whereby the adhesive member 40 hardens, and a fuel cell assembly 10 is produced in which the electrode member 2, the gasket 30, and the separator 50 are integrated via the adhesive member 40 (see Figure 2 above).

[0035] [Action and effect] Next, the effects of the fuel cell assembly and its manufacturing method of this embodiment will be described. In the fuel cell assembly 10 of this embodiment, the gasket 30 is made of EPDM. This makes the gasket 30 highly durable. Furthermore, because silicone rubber is not used, there is little deterioration in sealing performance and little contamination of the MEA 20 by decomposition products.

[0036] The adhesive member 40 has excellent adhesive properties because it contains an acid-modified olefin thermoplastic resin. Portions of the adhesive member 40 are impregnated into the upper gas diffusion layer 21 and the lower gas diffusion layer 22. This achieves high adhesiveness and sealing properties. The entire upper surface of the adhesive member 40 is covered with the gasket 30. The thickness T3 of the portion where the gasket 30 and the adhesive member 40 are stacked is greater than the thickness of the electrode member 2. This improves sealing properties when fuel cell assemblies 10 are stacked to form a fuel cell. Covering the entire upper surface of the adhesive member 40 with the gasket 30 reduces tackiness of the adhesive member 40 between adjacent cells. This reduces the likelihood of the adhesive member 40 leaving marks on stacked components. Furthermore, when some cells need repair or replacement, the cells can be easily removed, improving repairability. The adhesive member 40 covers the outer peripheral end surface of the electrolyte membrane of the MEA 20. This protects and reinforces the electrolyte membrane, suppressing deformation and improving sealing properties. The thickness T2 of the adhesive member 40 is greater than the thickness T1 of the lower gas diffusion layer 22. This ensures the strength and adhesiveness of the adhesive member 40. In addition, deformation of the electrolyte membrane can be suppressed, enhancing durability and improving handleability.

[0037] In the fuel cell assembly 10, the separator 50 is integrated with the electrode member 2 and the gasket 30. This simplifies the stacking process of the fuel cell assembly 10 and reduces misalignment of the components. This improves workability and productivity. Furthermore, the adhesive member 40 and the separator 50 are bonded together, improving sealing performance.

[0038] The manufacturing method for a fuel cell assembly of this embodiment is included in the concept of the first and third manufacturing methods of the present disclosure. According to the manufacturing method for a fuel cell assembly of this embodiment, in the gasket molding step, the gasket 30 is manufactured in advance from a rubber composition containing EPDM. By separating the manufacturing process for the gasket 30 from the process for integrating the electrode member 2, the gasket 30 can be manufactured using solid rubber, which has lower fluidity compared to liquid materials. Furthermore, since the molding temperature can be set to a high temperature of around 200°C regardless of the heat resistance temperature of the electrolyte membrane, the gasket 30 can be manufactured in a short time. Thus, according to the manufacturing method for a fuel cell assembly of this embodiment, a highly durable gasket 30 can be manufactured with high productivity.

[0039] In the integration process, the adhesive member 40 is melted and hardened by hot pressing, easily integrating the electrode member 2, gasket 30, and separator 50. The melting point of the thermal acid-modified olefin thermoplastic resin that is the material of the adhesive member 40 is approximately 130°C, and the hot pressing is performed at 140°C, so there is little risk of the electrolyte membrane being altered during heating. The molten adhesive member 40 impregnates the upper gas diffusion layer 21 and the lower gas diffusion layer 22 of the electrode member 2, thereby improving adhesion and sealing properties.

[0040] Second Embodiment The fuel cell assembly and manufacturing method thereof of this embodiment differ from those of the first embodiment only in part of the manufacturing method, and that is, in the placement step, instead of applying an adhesive member to the separator, the adhesive member is fixed to the molded gasket in advance. Here, the differences will mainly be described.

[0041] The manufacturing method of the fuel cell assembly of this embodiment includes a gasket molding step, an arrangement step, and an integration step, similar to the first embodiment, but an adhesive member fixing step is added to the arrangement step. In this embodiment, the adhesive member fixing step is performed first in the arrangement step, and the adhesive member is adhered to the gasket. FIG. 7 shows a schematic cross-sectional view of the gasket to which the adhesive member is adhered in the adhesive member fixing step. FIG. 8 shows a schematic cross-sectional view of each component in the arrangement step.

[0042] First, as shown in FIG. 7 , after the gasket molding process (see FIG. 3 ), with only the upper mold 80 removed, the adhesive material 40 is applied in a frame shape to the upper surface of the portion of the resulting gasket 30 corresponding to the overlapping portion 301. The adhesive material 40 is applied using a dispenser while heated to a temperature of 150°C or higher to ensure sufficient fluidity, similar to the placement process of the first embodiment. Then, using another mold, the adhesive material 40 is molded into a predetermined shape and cooled. In this manner, the gasket 30 with the adhesive material is manufactured. Next, as shown in FIG. 8 , the manufactured gasket 30 with the adhesive material is inverted and placed on the upper surface of the separator 50, and the electrode member 2 is placed inside the adhesive material 40. Then, similar to the integration process of the first embodiment, the adhesive material 40 is melted by hot pressing and then hardened, integrating the electrode member 2, gasket 30, and separator 50 with the adhesive material 40.

[0043] According to the manufacturing method for a fuel cell assembly of this embodiment, in the adhesive member fixing step, the adhesive member 40 is fixed to the surface of the gasket 30 in advance. This reinforces the gasket 30, improving the ease of handling when placing the gasket 30 in the subsequent integration step. Furthermore, since the electrode member 2 can be placed in accordance with the frame of the adhesive member 40, positioning of the electrode member 2 when placing it is easy.

[0044] Third Embodiment The fuel cell assembly and manufacturing method thereof of this embodiment differ from those of the first embodiment in the shapes of the adhesive members and gaskets, and in that the adhesive members are formed by injection molding. Here, the differences will be mainly described.

[0045] [Configuration of fuel cell assembly] First, the configuration of the fuel cell assembly of this embodiment will be described. Fig. 9 shows a partial cross-sectional view of the fuel cell assembly of this embodiment. In Fig. 9, parts corresponding to those in Fig. 2 are designated by the same reference numerals. As shown in Fig. 9, the fuel cell assembly 11 includes an electrode member 2, a gasket 31, an adhesive member 41, and a separator 50.

[0046] The gasket 31 has a frame shape when viewed from above and is disposed on the outside of the electrode member 2. The gasket 31 is made of the same material as the gasket 30 of the first embodiment, i.e., a cross-linked product of a rubber composition containing EPDM. The gasket 31 has a main body 310 and an overlapping portion 311. The main body 310 is disposed on the outside of the frame and has two lip portions 312 that protrude in the thickness direction. The tops of the two lip portions 312 are curved. The overlapping portion 311 is disposed on the inside of the frame and is laminated on a part of the adhesive member 41.

[0047] The adhesive member 41 has a frame shape when viewed from above and is disposed on the outer side of the electrode member 2. The adhesive member 41 is disposed between the electrode member 2 and the gasket 31 in the planar direction. The cross section of the adhesive member 41 in the thickness direction is L-shaped, and the outwardly protruding portion is laminated on the overlapping portion 311 of the gasket 31. A portion of the lower surface of the adhesive member 41 is covered by the gasket 31. The upper surface of the adhesive member 41 is flush with the main body portion 310 of the gasket 31, excluding the lip portion 312. The total thickness T3 of the overlapping portion 311 of the gasket 31 and the adhesive member 41 is the same as the thickness of the electrode member 2. The thickness T2 of the adhesive member 41 in contact with the electrode member 2 is the same as the thickness of the electrode member 2 and is greater than the thicknesses T1 of the upper gas diffusion layer 21 and the lower gas diffusion layer 22. The adhesive member 41 is made of the same material as the adhesive member 40 of the first embodiment, and contains an acid-modified olefin-based thermoplastic resin. A portion of the adhesive member 41 is impregnated into the upper impregnated portion 210 of the upper gas diffusion layer 21 and the lower impregnated portion 220 of the lower gas diffusion layer 22 of the electrode member 2. In addition, the adhesive member 41 is adhered to the members with which it is in contact, specifically, the outer peripheral end face of the MEA 20 including the electrolyte membrane, the gasket 31, and the separator 50. In this way, the electrode member 2, the gasket 31, and the separator 50 are integrated by the adhesive member 41.

[0048] [Method of manufacturing fuel cell assembly] Next, a method for manufacturing the fuel cell assembly of this embodiment will be described. The method for manufacturing the fuel cell assembly of this embodiment includes a gasket molding step, an arrangement step, and an integration step. The gasket molding step is the same as in the first embodiment, so a description thereof will be omitted.

[0049] (1) Placement process Fig. 10 shows a cross-sectional view of each component in the placement step. As shown in Fig. 10, in this step, the separator 50 is placed in the lower mold 85 of the forming die, and the electrode member 2 and the gasket 31 are placed in predetermined positions on the upper surface of the separator 50. A space is provided between the electrode member 2 and the gasket 31 in the planar direction, into which a liquid composition, which is the material for the adhesive member 41, is injected in the subsequent integration step.

[0050] (2) Integration process In this step, a liquid composition is injected into a mold and cured, thereby integrating the electrode member 2, gasket 31, and separator 50 with an adhesive member 41, which is a cured product of the liquid composition. FIG. 11 shows a cross-sectional schematic diagram of the mold in the integration step. As shown in FIG. 11, the mold 8 includes an upper mold 84 and a lower mold 85. The separator 50, electrode member 2, and gasket 31 are arranged in the lower mold 85. By combining the upper mold 84 and the lower mold 85, a cavity 86 is defined that has a shape symmetrical to that of the adhesive member 41. The upper mold 84 has a gate 87 that is connected to the cavity 86.

[0051] First, the mold 8 is clamped, and a liquid composition 410 containing an acid-modified olefin-based thermoplastic resin is injected from the nozzle of the injection molding machine through a runner (not shown) and gate 87 into the cavity 86. The liquid composition 410 is heated to approximately 140°C. As indicated by the white arrows in FIG. 11 , the injected liquid composition impregnates the outer peripheral ends of the upper gas diffusion layer 21 and the lower gas diffusion layer 22, and also adheres to the outer peripheral end face of the MEA 20, the gasket 31, and the separator 50. The mold 8 is then cooled, and the liquid composition 410 hardens to become the adhesive member 41. In this manner, a fuel cell assembly 11 is produced in which the electrode member 2, the gasket 31, and the separator 50 are integrated via the adhesive member 41 (see FIG. 9 above).

[0052] [Action and effect] Next, the effects of the fuel cell assembly and its manufacturing method according to this embodiment will be described. The manufacturing method for the fuel cell assembly according to this embodiment is included in the concepts of the second and fourth manufacturing methods of the present disclosure. According to this manufacturing method for the fuel cell assembly, in the integration step, the separator 50, the electrode member 2, and the gasket 31 are placed in a mold 8, and then a liquid composition 410 containing a thermal acid-modified olefin thermoplastic resin is injected and cured. This allows the electrode member 2, the gasket 31, and the separator 50 to be easily integrated. Because the liquid composition 410 is injection-molded at approximately 140°C, there is little risk of the electrolyte membrane being altered during heating. The liquid composition 410 impregnates the upper gas diffusion layer 21 and the lower gas diffusion layer 22 of the electrode member 2. This improves adhesion and sealing properties. According to this manufacturing method for the fuel cell assembly according to this embodiment, the manufacturing of the fuel cell assembly 11 is more efficient, thereby further increasing productivity.

[0053] In the method of applying the adhesive material in advance, as in the first and second embodiments, the amount of adhesive material is finite, and therefore there is a risk of insufficient adhesive material when the gap between the gasket and the electrode member is large or when the gap size varies greatly, etc. In this regard, with the injection molding of this embodiment, the liquid composition flows and fills the gap between the gasket 31 and the electrode member 2 without excess or deficiency, which is effective when the gap is large or when the gap size varies greatly, etc.

[0054] <Fourth embodiment> The fuel cell assembly of this embodiment and its manufacturing method differ from those of the first embodiment in the size of the gas diffusion layer in the electrode member and the bonding form of the adhesive member. Here, the differences will be mainly explained. FIG. 12 shows a partial cross-sectional view of the fuel cell assembly of this embodiment. In FIG. 12, parts corresponding to those in FIG. 2 are designated by the same reference numerals. As shown in FIG. 12, the fuel cell assembly 12 includes an electrode member 2, a gasket 30, an adhesive member 42, and a separator 50.

[0055] The electrode member 2 comprises an MEA 20 and a pair of upper and lower gas diffusion layers 23 and 24 disposed on both sides of the MEA 20 in the thickness direction. The upper and lower gas diffusion layers 23 and 24 have the same configuration but differ in size (area) in the planar direction. That is, the area of ​​the upper gas diffusion layer 23 is smaller than the area of ​​the lower gas diffusion layer 24. Therefore, when the electrode member 2 is viewed from above, the outer edge of the MEA 20 is exposed. An upper impregnated portion 230 impregnated with an adhesive member 42 is disposed at the outer peripheral edge of the upper gas diffusion layer 23. Similarly, a lower impregnated portion 240 impregnated with an adhesive member 42 is disposed at the outer peripheral edge of the lower gas diffusion layer 24.

[0056] The adhesive member 42 has a frame shape when viewed from above and is disposed on the outer side of the electrode member 2. The thickness T2 of the adhesive member 42 is the same as that of the electrode member 2 and is greater than the thicknesses T1 of the upper gas diffusion layer 23 and the lower gas diffusion layer 24. The upper surface of the adhesive member 42 is covered by the overlapping portion 301 of the gasket 30. The total thickness T3 of the overlapping portion 301 of the gasket 30 and the adhesive member 42 is greater than the thickness of the electrode member 2. The adhesive member 42 is made of the same material as the adhesive member 40 of the first embodiment, and contains an acid-modified olefin-based thermoplastic resin. A portion of the adhesive member 42 impregnates the upper impregnation portion 230 of the upper gas diffusion layer 23 and the lower impregnation portion 240 of the lower gas diffusion layer 24 of the electrode member 2. The adhesive member 42 is also adhered to the upper surface of the MEA 20 exposed on the upper gas diffusion layer 23 side. Furthermore, the adhesive member 42 also adheres to the outer peripheral end surface of the MEA 20 including the electrolyte membrane, the gasket 30, and the separator 50. In this way, the electrode member 2, the gasket 30, and the separator 50 are integrated by the adhesive member 42. The manufacturing method for the fuel cell assembly 12 is the same as the manufacturing method for the first embodiment.

[0057] In the fuel cell assembly 12 of this embodiment, the area of ​​the upper gas diffusion layer 23 is smaller than the area of ​​the lower gas diffusion layer 24, and an adhesive member 42 is adhered to the upper surface of the MEA 20 exposed upward. By adopting such a configuration, it is possible to suppress cross leakage that is likely to occur at the outer peripheral edge of the electrode member 2. As a result, a decrease in power generation performance and deterioration of the electrolyte membrane are suppressed.

[0058] Fifth Embodiment The fuel cell assembly and its manufacturing method of this embodiment differ from those of the first embodiment in the size of the gas diffusion layer in the electrode member, the bonding form of the adhesive member, and the shape of the gasket. Here, the differences will be mainly explained. FIG. 13 shows a partial cross-sectional view of the fuel cell assembly of this embodiment. In FIG. 13, parts corresponding to those in FIG. 2 are designated by the same reference numerals. As shown in FIG. 13, the fuel cell assembly 13 includes an electrode member 2, a gasket 32, an adhesive member 43, and a separator 50.

[0059] The electrode member 2 comprises an MEA 20 and a pair of upper and lower gas diffusion layers 25 and 26 arranged on both sides of the MEA 20 in the thickness direction. The upper and lower gas diffusion layers 25 and 26 have the same configuration and size. The size (area) of the MEA 20 in the planar direction is larger than those of the upper and lower gas diffusion layers 25 and 26. Therefore, when the electrode member 2 is viewed from above, the outer edge of the MEA 20 is exposed and protrudes outward.

[0060] The adhesive member 43 has a frame shape when viewed from above and is disposed on the outside of the electrode member 2. The thickness T2 of the adhesive member 43 is the same as the total thickness of the MEA 20 and the lower gas diffusion layer 26 and is greater than the thickness T1 of the lower gas diffusion layer 26. The adhesive member 43 is made of the same material as the adhesive member 40 of the first embodiment, and contains an acid-modified olefin-based thermoplastic resin. The adhesive member 43 is bonded to the lower surface and outer peripheral end surface of the MEA 20 that protrude outward from the electrode member 2, and to the outer peripheral end surface of the lower gas diffusion layer 26. The adhesive member 43 is also bonded to the gasket 32 ​​and the separator 50. In this way, the electrode member 2, the gasket 32, and the separator 50 are integrated by the adhesive member 43.

[0061] The gasket 32 ​​has a frame shape when viewed from above and is disposed outside the electrode member 2. The gasket 32 ​​is made of the same material as the gasket 30 of the first embodiment, i.e., a cross-linked product of a rubber composition containing EPDM. The gasket 32 ​​has a main body 320 and an overlapping portion 321. The main body 320 is disposed outside the frame and has two lip portions 322 that protrude in the thickness direction. The tops of the two lip portions 322 are curved. The overlapping portion 321 is disposed inside the frame and covers the upper surface of the adhesive member 43, the outer peripheral end surface of the upper gas diffusion layer 25, and the upper surface of the MEA 20 that protrudes outward from the electrode member 2. The total thickness T3 of the overlapping portion 321 of the gasket 32 ​​and the adhesive member 43 is greater than the thickness of the electrode member 2. The manufacturing method for the fuel cell assembly 13 is the same as that of the first embodiment.

[0062] In the fuel cell assembly 13 of this embodiment, the area of ​​the MEA 20 is larger than the areas of the upper gas diffusion layer 25 and the lower gas diffusion layer 26, and the outer edge of the MEA 20 protrudes outward. The adhesive member 43 is adhered to the exposed lower surface and outer peripheral end surface of the MEA 20 and the outer peripheral end surface of the lower gas diffusion layer 26. The thickness T2 of the adhesive member 43 is the same as the total thickness of the MEA 20 and the lower gas diffusion layer 26 and is larger than the thickness T1 of the lower gas diffusion layer 26. The exposed upper surface of the MEA 20 and the outer peripheral end surface of the upper gas diffusion layer 25 are covered with a gasket 32. This configuration achieves high sealing performance for the electrode member 2. Furthermore, the strength and adhesiveness of the adhesive member 43 are ensured, suppressing deformation of the electrolyte membrane.

[0063] <Other embodiments> The fuel cell assembly and the manufacturing method thereof according to the present disclosure have been described above. However, the embodiments are not limited to the above-described embodiments. Various modifications and improvements that can be made by those skilled in the art are also possible.

[0064] The fuel cell assembly of the present disclosure may include, as essential components, a specified electrode member, a gasket, and an adhesive member. The fuel cell assembly of the present disclosure may include other components in addition to these essential components, and the types of these components are not limited. In the above-described embodiment, the fuel cell assembly and its manufacturing method of the present disclosure are shown as including a separator. However, the fuel cell assembly and its manufacturing method of the present disclosure may also be implemented in a configuration that does not include a separator. The first manufacturing method or the second manufacturing method of the present disclosure also corresponds to a manufacturing method of a fuel cell assembly of the present disclosure that does not include a separator. Even in a configuration in which the fuel cell assembly includes a separator, the separator does not necessarily need to be integrated with an adhesive member. For example, a fuel cell assembly may be constructed by stacking a specified gasketed electrode member, in which the electrode member and the gasket are integrated with an adhesive member, on a separator.

[0065] [Electrode material] Among the components of the fuel cell assembly of the present disclosure, the electrode member includes an MEA and a gas diffusion layer. The MEA includes an electrolyte membrane and a pair of electrode catalyst layers disposed on both sides of the electrolyte membrane. The electrolyte membrane may be a proton-conductive ion exchange membrane used in fuel cells. The electrode catalyst layer may include a conductive carrier carrying a catalyst such as platinum or a platinum alloy. The electrode catalyst layer does not necessarily have to be formed on the entire surface of the electrolyte membrane. The electrode catalyst layer may be appropriately formed on the surface of the electrolyte membrane depending on the power generation region of the MEA. The gas diffusion layer may be made of a porous carbon material such as carbon paper or carbon cloth, or a porous metal material such as a metal mesh.

[0066] The gas diffusion layer may be disposed on one or both sides of the MEA in the thickness direction. The gas diffusion layer may be a single layer or two or more layers. When gas diffusion layers are disposed on both sides of the MEA in the thickness direction, the thickness and size (area) of the gas diffusion layer on one side and the other side in the thickness direction may be the same or different. For example, if the area of ​​the gas diffusion layer disposed on one side is smaller than the area of ​​the gas diffusion layer disposed on the other side, the outer edge of the MEA will be exposed on the side of the gas diffusion layer with the smaller area. In this case, it is desirable to adhere an adhesive member to the exposed outer edge of the MEA from the viewpoint of protecting the electrolyte membrane. Furthermore, if the area of ​​the MEA is larger than the area of ​​the gas diffusion layer, the outer edge of the MEA will also be exposed. In this case, it is also desirable to adhere an adhesive member to the exposed outer edge of the MEA from the viewpoint of protecting the electrolyte membrane.

[0067] [gasket] The gasket is manufactured using solid rubber. For example, a rubber composition containing solid rubber as the rubber component may be manufactured by injection molding, press molding, or the like. Solid rubber other than silicone rubber is preferable, and examples of the solid rubber include EPDM, fluororubber, butyl rubber (IIR), ethylene-propylene rubber (EPM), acrylonitrile-butadiene rubber (NBR), hydrogenated acrylonitrile-butadiene rubber (H-NBR), styrene-butadiene rubber (SBR), and butadiene rubber (BR). Considering the durability of the gasket, EPDM and fluororubber are preferred. In addition to the rubber component, the rubber composition may contain a crosslinking agent, a crosslinking aid, a plasticizer, a reinforcing agent, an antioxidant, a processing aid, and the like. An organic peroxide is preferably used as the crosslinking agent because it does not contain volatile components such as sulfur. In the above embodiment, a lip is provided on the gasket to improve sealing performance when fuel cell assemblies are stacked. The shape and thickness of the gasket, including whether or not to include a lip, may be determined as appropriate.

[0068] [Separator] Examples of separator materials include stainless steel, titanium, copper, magnesium, aluminum, carbon, graphite, ceramics, and conductive resins (thermoplastic or thermosetting resins containing carbon, graphite, or polyacrylonitrile-based carbon fibers). Furthermore, a thin carbon film, such as a diamond-like carbon film (DLC film) or a graphite film, may be formed on the surface of a main body made of these materials by physical vapor deposition (PVD), chemical vapor deposition (CVD), or other processes. The configuration of the separator, including the flow paths and through-holes formed therein, is not limited.

[0069] [Adhesive material] The adhesive member may contain a thermoplastic polymer and be capable of adhering to at least the electrode member and the gasket. Considering the operating temperature of the fuel cell and the heat resistance temperature of the electrolyte membrane, it is desirable to select a thermoplastic polymer with a melting point of 70°C or higher and 170°C or lower. A melting point of 140°C or lower is more preferable. Examples of thermoplastic polymers with relatively low melting points include olefin-based thermoplastic resins such as polyethylene and polypropylene. Among these, acid-modified olefin-based thermoplastic resins are preferable from the viewpoint of good adhesiveness. Acid-modified olefin-based thermoplastic resins refer to olefin-based thermoplastic resins modified with acid, acid anhydride, acid ester, metallocene, or the like. The acid modification may be performed by grafting an acid component onto the olefin-based thermoplastic resin, copolymerizing it, or a combination of these.

[0070] The shape of the adhesive member is not particularly limited as long as it can adhere to the electrode member and the gasket and integrate them. If the fuel cell assembly includes a separator, the adhesive member may also adhere to the separator, integrating the separator with the electrode member and the gasket. The adhesive member may be adhered to the electrode member by impregnating the gas diffusion layer, or by adhering to the MEA, or both. When the adhesive member is impregnated into the gas diffusion layer, adhesion and sealing properties are improved. When the adhesive member is adhered to the MEA, the electrolyte membrane is protected by the adhesive member, thereby suppressing deformation, damage, and the like of the electrolyte membrane. When the adhesive member is adhered to the MEA, it may be adhered to the electrolyte membrane of the MEA or to an electrode catalyst layer disposed on the surface of the electrolyte membrane. Even when the adhesive member is impregnated into the gas diffusion layer and not adhered to both sides of the MEA in the thickness direction, the adhesive member covers at least the outer peripheral end surface of the electrolyte membrane. This protects the electrolyte membrane and improves sealing properties.

[0071] From the viewpoint of the strength and adhesiveness of the adhesive member, the thickness of the adhesive member is equal to or greater than the thickness of the gas diffusion layer disposed on one side of the MEA. In this specification, "thickness" refers to the length in the stacking direction of the electrode members. When comparing the thickness of the adhesive member with the thickness of the gas diffusion layer, the thickness of the adhesive member in contact with the electrode member is compared. For example, in the third embodiment described above, the thickness of the adhesive member 41 differs between the inner and outer directions of the frame. In this case, the thickness T2 of the portion in contact with the electrode member 2 is compared with the thickness T1 of the gas diffusion layer (lower gas diffusion layer 22 or upper gas diffusion layer 21). Furthermore, from the viewpoint of improving sealing performance when fuel cell assemblies are stacked to form a fuel cell, it is desirable that the thickness of the portion where the gasket and adhesive member are stacked in the stacking direction of the electrode members be equal to or greater than the thickness of the electrode members.

[0072] From the viewpoint of sealing performance and repairability of the fuel cell assembly, at least a portion of one thickness-wise surface of the adhesive member is covered with a gasket. The one thickness-wise surface of the adhesive member may be the upper surface in the first embodiment or the lower surface in the third embodiment. The portion of the adhesive member covered with the gasket may be one or both thickness-wise surfaces, or the entire surface or a portion thereof. Alternatively, a fuel cell assembly may be implemented in which one thickness-wise surface of the adhesive member is not covered with a gasket at all. In this form, the gasket does not have an overlapping portion (such as overlapping portion 301 in the first embodiment or overlapping portion 311 in the third embodiment) that extends from the main body portion to overlap the adhesive member. This simplifies the shape of the gasket, making it easier to manufacture the gasket.

[0073] [Method of manufacturing fuel cell assembly] The manufacturing method of the fuel cell assembly of the present disclosure is characterized in that a gasket is molded in advance, and the molded gasket and electrode member are bonded and integrated by utilizing the melting and curing of a thermoplastic polymer. Depending on the method of supplying the adhesive member containing the thermoplastic polymer, the following forms (a) and (b) can be mentioned. (a) A method for manufacturing a fuel cell assembly, comprising: a gasket molding step of molding a gasket from solid rubber; an arrangement step of arranging an electrode member having a membrane electrode assembly having an electrolyte membrane and an electrode catalyst layer and a gas diffusion layer disposed on at least one of both surfaces in the thickness direction of the membrane electrode assembly, the molded gasket, and an adhesive member having a thermoplastic polymer; and an integration step of melting and curing the adhesive member to integrate the electrode member and the gasket with the adhesive member. (b) A method for manufacturing a fuel cell assembly, comprising: a gasket molding step of molding a gasket from solid rubber; an arrangement step of arranging the molded gasket and an electrode member having a membrane electrode assembly having an electrolyte membrane and an electrode catalyst layer and a gas diffusion layer disposed on at least one of both surfaces in the thickness direction of the membrane electrode assembly, into a molding die; and an integration step of injecting a liquid composition containing a thermoplastic polymer into the molding die and curing it, thereby integrating the electrode member and the gasket with an adhesive member that is a cured product of the liquid composition.

[0074] In the gasket molding process, a rubber composition containing a solid rubber as a rubber component is maintained at a predetermined temperature for a predetermined time to mold a gasket. The gasket can be molded by a known method such as injection molding or press molding.

[0075] When an adhesive member having a thermoplastic polymer is placed in the placement step, the adhesive member may be placed on the surface of the gasket or on the surface of a substrate such as a separator. Fixing the adhesive member to the surface of the gasket in advance, as in the second embodiment, reinforces the gasket, improving handling when placing the gasket. Furthermore, the electrode member can be placed according to the frame of the adhesive member, making it easier to position the electrode member when placing it. The adhesive member placed in the placement step may be solid or liquid. Examples of methods for placing the adhesive member include applying it with a brush, using a coating machine such as a dispenser, or a spray, using a mold, and forming the adhesive member into a frame-shaped sheet beforehand and then placing it.

[0076] In the integration process, when the adhesive member is melted and cured, a hot press or the like may be used. Alternatively, when a liquid composition containing a thermoplastic polymer is injected into a mold and cured, an injection molding machine or the like may be used. When melting and adhering the adhesive member, including the form of injecting the liquid composition, it is not necessarily necessary to apply pressure. When applying pressure to the adhesive member in a molten state, it becomes easier to impregnate the gas diffusion layer. The heating temperature for melting the adhesive member may be appropriately determined taking into consideration the heat resistance temperature of the electrolyte membrane, the melting point of the thermoplastic polymer, the environmental temperature in which the fuel cell is used, etc., and may be, for example, 110°C or higher and 150°C or lower. [Explanation of symbols]

[0077] 10, 11, 12, 13: fuel cell assembly, 2: electrode member, 20: MEA, 21, 23, 25: upper gas diffusion layer, 22, 24, 26: lower gas diffusion layer, 210, 230: upper impregnated portion, 220, 240: lower impregnated portion, 30, 31, 32: gasket, 300, 310, 320: main body portion, 301, 311, 321: overlapping portion, 302, 312, 322: lip portion, 40, 41, 42, 43: adhesive member, 410: liquid composition, 50: separator, 8: molding die, 80, 84: upper die, 81, 85: lower die, 82, 86: cavity, 83: pressing member, 87: gate.

Claims

1. an electrode member having a membrane electrode assembly having an electrolyte membrane and an electrode catalyst layer, and a gas diffusion layer disposed on at least one of both surfaces of the membrane electrode assembly in the thickness direction; A direction intersecting the stacking direction of the electrode members is defined as a surface direction, a solid rubber gasket arranged in a frame shape on the outer side of the electrode member in the surface direction; an adhesive member comprising a thermoplastic polymer, the adhesive member being arranged in a frame shape on the outer side of the electrode member in the planar direction separately from the gasket, and adhering to the electrode member and the gasket to integrate the electrode member and the gasket; Equipped with the adhesive member is adhered to the electrode member by at least one of impregnation into the gas diffusion layer and adhesion to the membrane electrode assembly; the adhesive member covers at least the outer peripheral end surface of the electrolyte membrane; a thickness of the adhesive member in the stacking direction of the electrode members that is equal to or greater than a thickness of the gas diffusion layer that is disposed on one side of the membrane electrode assembly, and at least a portion of one surface in the thickness direction of the adhesive member is covered with the gasket.

2. the gas diffusion layers are disposed on both surfaces of the membrane electrode assembly in the thickness direction, 2. The fuel cell assembly according to claim 1, wherein the adhesive member is impregnated into at least one of the two gas diffusion layers.

3. the gas diffusion layers are disposed on both surfaces of the membrane electrode assembly in the thickness direction, When the electrode member is viewed from the stacking direction, the sizes of the two gas diffusion layers in the planar direction are different, 3. The fuel cell assembly according to claim 1, wherein the adhesive member is adhered to the membrane electrode assembly exposed on the smaller gas diffusion layer side.

4. When the electrode members are viewed from the stacking direction, the size of the membrane electrode assembly in the planar direction is larger than the size of the gas diffusion layer in the planar direction, 4. The fuel cell assembly according to claim 1, wherein the adhesive member is adhered to at least one surface of the membrane electrode assembly that protrudes outward.

5. 5. The fuel cell assembly according to claim 1, wherein the thickness of the portion where the gasket and the adhesive member are stacked in the stacking direction of the electrode members is equal to or greater than the thickness of the electrode members.

6. The battery further includes a separator laminated on the electrode member and the gasket, 6. The fuel cell assembly according to claim 1, wherein the adhesive member adheres to the electrode member, the gasket, and the separator to integrate the electrode member, the gasket, and the separator.

7. 7. The fuel cell assembly according to claim 1, wherein the solid rubber is ethylene-propylene-diene rubber (EPDM) or fluororubber.

8. 8. The fuel cell assembly according to claim 1, wherein the thermoplastic polymer comprises an olefin-based thermoplastic resin modified with an acid.

9. 10. A method for manufacturing a fuel cell assembly according to claim 1, comprising the steps of: a gasket molding process for molding a gasket from solid rubber; an arrangement step of arranging an electrode member having a membrane electrode assembly having an electrolyte membrane and an electrode catalyst layer, and a gas diffusion layer disposed on at least one of both surfaces in the thickness direction of the membrane electrode assembly, the molded gasket, and an adhesive member having a thermoplastic polymer; an integration step of melting and curing the adhesive member to integrate the electrode member and the gasket with the adhesive member; 10. A method for manufacturing a fuel cell assembly, comprising:

10. 10. A method for manufacturing a fuel cell assembly according to claim 1, comprising the steps of: a gasket molding process for molding a gasket from solid rubber; an arrangement step of arranging, in a molding die, an electrode member having a membrane electrode assembly having an electrolyte membrane and an electrode catalyst layer, and a gas diffusion layer disposed on at least one of both surfaces in the thickness direction of the membrane electrode assembly, and the molded gasket; an integration step of injecting a liquid composition containing a thermoplastic polymer into the mold and curing the liquid composition to integrate the electrode member and the gasket with an adhesive member that is a cured product of the liquid composition; 10. A method for manufacturing a fuel cell assembly, comprising:

11. 7. A method for manufacturing a fuel cell assembly according to claim 6, comprising the steps of: a gasket molding process for molding a gasket from solid rubber; an arrangement step of arranging, on one surface of a separator, an electrode member having a membrane electrode assembly having an electrolyte membrane and an electrode catalyst layer, and a gas diffusion layer disposed on at least one surface of both surfaces in the thickness direction of the membrane electrode assembly, the molded gasket, and an adhesive member having a thermoplastic polymer; an integration step of melting and curing the adhesive member to integrate the electrode member, the gasket, and the separator with the adhesive member; 10. A method for manufacturing a fuel cell assembly, comprising:

12. 7. A method for manufacturing a fuel cell assembly according to claim 6, comprising the steps of: a gasket molding process for molding a gasket from solid rubber; an arrangement step of arranging a separator in a molding die, and further arranging, on one surface of the separator, an electrode member having a membrane electrode assembly having an electrolyte membrane and an electrode catalyst layer, and a gas diffusion layer disposed on at least one surface of both surfaces of the membrane electrode assembly in the thickness direction, and the molded gasket; an integration step of injecting a liquid composition containing a thermoplastic polymer into the mold and curing the liquid composition to integrate the electrode member, the gasket, and the separator with an adhesive member that is a cured product of the liquid composition; 10. A method for manufacturing a fuel cell assembly, comprising:

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