JP6432398B2 - Fuel cell single cell - Google Patents

Description

  The present invention relates to a fuel cell single cell.

  A membrane electrode assembly in which an electrode catalyst layer is formed on each side surface of the electrolyte membrane, and an outer peripheral edge portion on one side surface of the membrane electrode assembly while remaining on both side surfaces of the membrane electrode assembly. A support frame with a gas diffusion layer arranged, an adhesive layer formed to cover the outer peripheral edge, a support frame fixed on the adhesive layer, and another adhesive layer having thermoplasticity at the peripheral part And a separator disposed on both sides of the support frame and the gas diffusion layer so as to contact the gas diffusion layer at the center portion, and the support frame includes a support frame body fixed to the separator, A fuel cell unit cell is known that includes a protrusion extending from the inner edge portion of the support frame body to the inside of the support frame body, the protrusion being fixed to the adhesive layer and thinner than the support frame body. Are (for example, see Patent Document 1).

JP 2013-251253 A

  In the above fuel cell unit cell, when another adhesive layer is heated in order to bond the separator and the support frame, not only another adhesive layer but also a separator and a support frame around another adhesive layer are included. A large area will be heated. However, in the case of using a metal as a separator and using a resin as a support frame, the linear expansion coefficient of the separator is relatively small, and the linear expansion coefficient of the support frame is relatively large, so in the cooling process after heating, The shrinkage amount of the support frame is larger than the shrinkage amount of the separator. As a result, the adhesive layer between the support frame and the membrane electrode assembly is pulled by the support frame, and a large tensile stress is generated in the adhesive layer. This tensile stress can also occur when the fuel cell unit cell is placed in a low-temperature environment when the fuel cell unit cell is used, for example, during cold operation. These tensile stresses may cause cracks in the adhesive layer or the membrane electrode assembly below the adhesive layer. A technique that suppresses the occurrence of cracks in the adhesive layer or the membrane electrode assembly under the adhesive layer is desired.

  According to the present invention, the membrane electrode assembly in which the electrode catalyst layers are respectively formed on both side surfaces of the electrolyte membrane, and the membrane electrode while leaving an outer peripheral edge on one side surface of the membrane electrode assembly. A gas diffusion layer disposed on each side surface of the joined body; an adhesive layer formed on the outer peripheral edge; a support frame fixed on the adhesive layer; The support frame and a separator disposed on each side surface of the gas diffusion layer so as to contact the gas diffusion layer at a central portion, and the support frame is supported by the separator. A frame body, and a projecting portion joined to the inner edge portion of the support frame body via a joint portion so as to extend from the inner edge portion of the support frame body to the inside of the support frame body. A protrusion that is fixed to the adhesive layer and is thinner than the support frame body, and the Young's modulus of the material forming the protrusion is lower than the Young's modulus of the material forming the support frame body , Fuel cell single cell.

  It can control that a crack arises in a membrane electrode assembly under an adhesive layer or an adhesive layer.

It is a disassembled perspective view which shows the structural example of a fuel cell single cell. It is a fragmentary sectional view which shows the structural example of a fuel cell single cell. It is sectional drawing which shows the structural example of a support frame. It is sectional drawing which shows the structural example of the support frame of another Example. It is a fragmentary sectional view which shows the process of the manufacturing method of a fuel cell single cell. It is a fragmentary sectional view which shows the process of the manufacturing method of a fuel cell single cell. It is a fragmentary sectional view which shows the process of the manufacturing method of a fuel cell single cell. It is a fragmentary sectional view which shows the process of the manufacturing method of a fuel cell single cell. It is a fragmentary sectional view which shows the process of the manufacturing method of a fuel cell single cell. It is sectional drawing which shows the structural example of the support frame of another Example. It is sectional drawing which shows the structural example of the support frame of another Example.

  The configuration of the single fuel cell will be described. FIG. 1 is an exploded perspective view showing a configuration example of a single fuel cell. The fuel cell single cell 1 includes a membrane electrode assembly 5. A cathode gas diffusion layer 3 c and an anode gas diffusion layer 3 a are respectively disposed on both side surfaces of the membrane electrode assembly 5, and a support frame 2 is disposed on the outer periphery of the membrane electrode assembly 5 via an adhesive layer 10. . On both side surfaces of the membrane electrode assembly 5 and the support frame 2, a cathode separator 4c and an anode separator 4a are disposed, respectively. Therefore, the fuel cell single cell 1 is formed by assembling the cathode separator 4c and the anode separator 4a on both sides of the membrane electrode assembly 5 having the gas diffusion layers 3c and 3a and the support frame 2, respectively.

  The central portion 4 cm of the cathode separator 4 c has a plurality of grooves for an oxidant gas supply path formed by integral molding on the membrane electrode assembly 5 side (side not shown). In the embodiment shown in FIG. 1, the plurality of grooves in the central portion 4 cm are unidirectional flow paths, and in another embodiment (not shown), serpentine type flow paths. Of the peripheral edge portion 4ce outside the central portion 4cm of the cathode separator 4c, in the vicinity of both ends in the longitudinal direction of the cathode separator 4c, through holes 6c1, 6c2 for oxidant gas manifolds and cooling water are provided so as to penetrate the cathode separator 4c. Manifold through holes 6w1 and 6w2 and fuel gas manifold through holes 6a1 and 6a2 are formed. On the side opposite to the membrane electrode assembly 5 (the side shown in the figure) in the peripheral portion 4ce, a recess 15 for receiving the seal member 14 is formed around each through-hole and around the central portion 4am.

  The central part 4am of the anode separator 4a has a plurality of grooves for the fuel gas supply path formed by integral molding on the membrane electrode assembly 5 side (the side shown in the figure). The plurality of grooves in the central portion 4am are unidirectional flow paths in the embodiment shown in FIG. 1, and are serpentine type flow paths in another embodiment (not shown). Of the peripheral edge portion 4ae outside the central portion 4am of the anode separator 4a, in the vicinity of both ends in the longitudinal direction of the anode separator 4a, the oxidant gas manifold through-holes 6c3 and 6c4, cooling water are provided so as to penetrate the anode separator 4a. Manifold through holes 6w3 and 6w4 and fuel gas manifold through holes 6a3 and 6a4 are formed. On the side opposite to the membrane electrode assembly 5 in the peripheral portion 4ae (the side not shown), a flat surface on which a sealing member 14 such as a gasket can be disposed is formed around each through-hole and around the central portion 4cm. .

  Near both ends in the longitudinal direction of the support frame 2, the oxidant gas manifold through-holes 6 c 5 and 6 c 6, the coolant manifold through-holes 6 w 5 and 6 w 6, and the fuel gas manifold through-holes are provided so as to penetrate the support frame 2. Mouth 6a5 and 6a6 are formed.

  When the fuel cell unit cell 1 is formed, when the cathode separator 4c and the anode separator 4a are assembled on both sides of the membrane electrode assembly 5 supported by the support frame 2, the cathode separator 4c, the support frame 2 and the anode separator 4a Oxidant gas manifold through holes 6c1, 6c5, 6c3 and 6c2, 6c6, 6c4, cooling water manifold through holes 6w1, 6w5, 6w3 and 6w2, 6w6, 6w4, and fuel gas manifold through holes 6a1, 6a5, 6a3 6a2, 6a6, 6a4 are aligned with each other in the thickness direction S. As a result, a passage extending in the thickness direction S, that is, an oxidant gas manifold, a coolant manifold, and a fuel gas manifold are defined as fluid passages.

  FIG. 2 shows a cross section of the fuel cell single cell 1 corresponding to E2-E2 of FIG. A fuel cell stack is formed by a stacked body in which a plurality of fuel cell single cells 1 are stacked in the thickness direction S of the fuel cell single cell 1. The single fuel cell 1 generates electric power by an electrochemical reaction between a fuel gas (example: hydrogen gas) and an oxidant gas (example: air). The electric power generated in the single fuel cell 1 is taken out of the fuel cell stack through a plurality of wires reaching the outside of the fuel cell stack from terminal plates arranged at both ends of the laminate. The electric power taken out from the fuel cell stack is supplied to, for example, an electric motor for driving an electric vehicle or a battery.

  The membrane electrode assembly 5 of the fuel cell single cell 1 includes an electrolyte membrane 5e, and a cathode electrode catalyst layer 5c and an anode electrode catalyst layer 5a formed on both sides of the electrolyte membrane 5e. The electrolyte membrane 5e, the cathode electrode catalyst layer 5c, and the anode electrode catalyst layer 5a have substantially the same size. When the cathode electrode catalyst layer 5c and the anode electrode catalyst layer 5a are arranged on both sides of the electrolyte membrane 5e to form the membrane electrode assembly 5, the electrolyte membrane 5e, the cathode electrode catalyst layer 5c, and the anode electrode catalyst layer 5a substantially overlap each other. . In another embodiment not shown, at least one of the cathode electrode catalyst layer 5c and the anode electrode catalyst layer 5a is smaller than the electrolyte membrane 5e.

  Examples of the material of the electrolyte membrane 5e include a fluorine-based polymer membrane having ion conductivity. In the embodiment shown in FIG. 2, an ion-exchange membrane having proton conductivity including perfluorosulfonic acid is used. Examples of the material for the cathode electrode catalyst layer 5c and the anode electrode catalyst layer 5a include catalyst-supported carbon that supports a catalyst such as platinum or a platinum alloy. In the embodiment shown in FIG. 2, catalyst-carrying carbon carrying a platinum alloy is used. In another embodiment not shown, an ionomer made of the same material as the electrolyte membrane 5e is further added to the catalyst-supporting carbon.

  The cathode gas diffusion layer 3 c is disposed on one side surface 52 of the membrane electrode assembly 5, that is, on the cathode electrode catalyst layer 5 c, whereby the cathode gas diffusion layer 3 c is electrically connected to the membrane electrode assembly 5. An anode gas diffusion layer 3a is disposed on the other side surface 51 of the membrane electrode assembly 5, that is, on the anode electrode catalyst layer 5a, whereby the anode gas diffusion layer 3a is electrically connected to the membrane electrode assembly 5. The The cathode gas diffusion layer 3 c has a size slightly smaller than that of the membrane electrode assembly 5. When the cathode gas diffusion layer 3c is disposed on one side surface 52 of the membrane electrode assembly 5, an outer peripheral edge 52e is formed in a frame shape on the one side surface 52 of the membrane electrode assembly 5 around the cathode gas diffusion layer 3c. The On the other hand, the anode gas diffusion layer 3 a has substantially the same size as the membrane electrode assembly 5. When the anode gas diffusion layer 3a is disposed on the other side surface 51 of the membrane electrode assembly 5, the membrane electrode assembly 5 and the anode gas diffusion layer 3a substantially overlap each other.

  Examples of the material for the cathode gas diffusion layer 3c and the anode gas diffusion layer 3a include conductive porous materials such as carbon porous materials such as carbon paper, carbon cloth, and glassy carbon, metal mesh, and foam metal. A metal porous body is mentioned. In the embodiment shown in FIG. 2, carbon cloth is used. In another embodiment (not shown), a material having high water repellency such as polytetrafluoroethylene is impregnated to such an extent that the porous body does not lose porosity. In still another embodiment (not shown), a water-repellent layer in which a material having strong water repellency and carbon particles are mixed is formed on the porous membrane electrode assembly 5 side.

  An adhesive layer 10 is formed on the outer peripheral edge 52e. The adhesive layer 10 is formed in the same frame shape as the outer peripheral edge portion 52e. In the embodiment shown in FIG. 2, the adhesive layer 10 is formed on the entire outer peripheral edge 52e so as to cover the outer peripheral edge 52e. The adhesive layer 10 has an outer portion 32 positioned on the outer side in the planar direction in the outer peripheral edge portion 52e, and an inner portion 31 positioned on the inner side in the planar direction in the outer peripheral edge portion 52e. The inner end portion of the inner portion 31 is in contact with the outer portion 3ce of the cathode gas diffusion layer 3c.

  The adhesive layer 10 is formed of a thermosetting adhesive or an ultraviolet (UV) curable adhesive. Examples of the material for the thermosetting adhesive layer 10 include an epoxy resin adhesive, and examples of the material for the ultraviolet curable adhesive layer 10 include UV curing using a radical polymerizable resin or a cationic polymerizable resin. Mold adhesives. In the embodiment shown in FIG. 2, a UV curable adhesive using a radical polymerizable resin is used. Examples of the method of applying the adhesive for the adhesive layer 10 include a screen printing method and a method of applying with a dispenser. In the embodiment shown in FIG. 2, a screen printing method is used.

  The support frame 2 is disposed on the adhesive layer 10. The support frame 2 has a frame shape, and supports the membrane electrode assembly 5 including the cathode gas diffusion layer 3 c and the anode gas diffusion layer 3 a on the outer periphery of the membrane electrode assembly 5. FIG. 3 is a cross-sectional view illustrating a configuration example of the support frame 2. In the embodiment shown in FIG. 3, the support frame 2 includes the support frame main body 20 and the support frame main body 20 via the joint portion 22 so as to extend from the inner edge portion 20 a of the support frame main body 20 to the inside of the support frame main body 20. And a protruding portion 21 joined to the inner edge portion 20a.

  In the embodiment shown in FIG. 3, the protruding portion 21 and the joining portion 22 are formed integrally, have the same thickness, and are thinner than the support frame main body 20. For example, the thickness of the inner edge portion 20a of the support frame main body 20 is 1 mm, and the thickness of the protruding portion 21 is 0.3 mm. As shown in FIG. 2, the protruding portion 21 is bonded to the outer peripheral edge 52 e of the membrane electrode assembly 5 by being bonded onto the outer portion 32 of the adhesive layer 10. When the protrusion 21 is bonded to the outer peripheral edge 52e of the membrane electrode assembly 5, a gap G is formed between the protrusion 21 and the outer portion 3ce of the cathode gas diffusion layer 3c. That is, the support frame 2 is disposed apart from the cathode gas diffusion layer 3c. On the other hand, as shown in FIG. 3, the joint portion 22 is joined to the support frame body 20 so that one side surface 22 s 1, the end surface 22 s 2, and the other side surface 22 s 3 are surrounded (covered) by the support frame body 20. . Therefore, the joint portion 22 is joined to the support frame main body 20 on the three surfaces 22s1, 22s2, and 22s3.

  In the embodiment shown in FIG. 3, the joint portion 22 is joined to the support frame body 20 so as to be surrounded by the inner edge portion 20a of the support frame body 20, but in another embodiment shown in FIG. 4, the joint portion 22 is joined to the support frame body. 20 is joined to the end face of the inner edge portion 20a. At this time, in the support frame 2 shown in FIG. 4, the end surface 22 s 4 of the joint portion 22 is joined to the support frame main body 20. Therefore, the joint area between the joint portion 22 and the support frame body 20, that is, the area of one surface 22s4 is equal to the cross-sectional area in the thickness direction S of the protrusion 21. On the other hand, in the support frame 2 shown in FIG. 3, the one side surface 22 s 1, the end surface 22 s 2, and the other side surface 22 s 3 are surrounded (covered) by the support frame body 20. In this case, the joint area between the joint portion 22 and the support frame main body 20, that is, the sum of the areas of the three surfaces 22s1, 22s2, and 22s3 is larger than the cross-sectional area of the protrusion 21 in the thickness direction S. 2 is larger than the bonding area. Therefore, compared with the support frame 2 of FIG. 4, the support frame 2 of FIG. 3 has a larger joint area between the joint portion 22 and the support frame main body 20, and therefore the joint between the joint portion 22 and the support frame main body 20 is peeled off. Since it becomes difficult, the fall of the intensity | strength of the support frame 2 can be suppressed. In addition, since the joining portion 22 and the support frame main body 20 are joined at the inner edge portion 20a of the support frame main body 20, that is, a portion thicker than the protruding portion 21, it is possible to suppress a decrease in the strength of the support frame 2.

  The support frame 2 is formed by injection molding using, for example, an injection molding machine. First, the material for the projecting portion 21 and the joining portion 22 is injected by the injection device into the first mold for the projecting portion 21 and the joining portion 22 attached to the mold clamping device. Thereby, the protrusion part 21 and the junction part 22 are integrally molded. Next, the projecting portion 21 and the joint portion 22 that are integrally formed by injection molding are placed in a second mold for the support frame main body 20 that is attached to the mold clamping device, and then the support frame main body 20 is formed by the injection device. Material is injected. Thereby, the support frame main body 20 is formed so as to surround the joint portion 22 of the integrally formed protrusion 21 and joint portion 22. At this time, the support frame main body 20 and the joint portion 22 are thermally welded on the three surfaces 22s1, 22s2, and 22s3 by the heat of the support frame main body 20 material at the time of injection molding of the support frame main body 20.

The support frame 2 is formed of a material having electrical insulation and airtightness. Further, the support frame main body 20 of the support frame 2 maintains the shape of the single fuel cell 1 so that the single fuel cell 1 is not easily deformed by an external force applied to the single fuel cell 1. It is made of a highly rigid material, that is, a material having a high Young's modulus. For example, a material having a Young's modulus of 1000 MPa or more is used. Examples of the material of the support frame main body 20 include resins such as a polypropylene resin, a phenol resin, an epoxy resin, a polyethylene terephthalate resin, and a polyethylene naphthalate resin. In the embodiment shown in FIG. 3, as the material of the support frame main body 20, a polypropylene resin that can transmit ultraviolet rays having a predetermined wavelength (for example, 365 nm) used for curing the adhesive layer 10 is used. Typical Young's modulus of these materials is, for example, about 1000 to 3000 MPa. The typical linear expansion coefficient of these materials is, for example, about 100 × 10 ⁻⁶ / ° C.

  On the other hand, the protruding portion 21 and the joining portion 22 of the support frame 2 are formed of a low-rigidity material, that is, a material having a low Young's modulus so that the supporting frame 2 is easily deformed by an external force. For example, a material having a Young's modulus smaller than that of the material forming the support frame body 20 such as a material having a Young's modulus of 500 MPa or less is used. Examples of the material forming the protruding portion 21 and the joining portion 22 include elastomer. Examples of the elastomer include a polyester resin, an olefin resin, a polyurethane resin, a styrene resin, and an amide resin. The elastomer is appropriately selected according to the material of the support frame body 20. For example, when a thermoplastic elastomer is used, it is preferable to use the same resin as the material of the support frame main body 20 for the molecular constraint component (hard segment) in order to strengthen the connection between the support frame main body 20 and the joint portion 22. . In the embodiment shown in FIG. 3, an elastomer in which ethylene-propylene rubber (EPDM, EPM) is mixed in polypropylene is used. Typical Young's modulus of these materials is, for example, about 10 to 500 MPa. In the embodiment shown in FIG. 3, the protruding portion 21 and the joining portion 22 are made of the same material, but in another embodiment (not shown), the protruding portion 21 and the joining portion 22 are made of different materials.

  A pair of cathode separator 4c and anode separator 4a sandwiching the membrane electrode assembly 5 having the cathode gas diffusion layer 3c and the anode gas diffusion layer 3a and the both sides of the support frame 2 are disposed.

  The peripheral portion 4ce of the cathode separator 4c is fixed to one side surface of the support frame body 20 of the support frame 2 with an adhesive layer 13c having thermoplasticity or thermosetting property. A central portion 4 cm inside the peripheral portion 4ce of the cathode separator 4c contacts the cathode gas diffusion layer 3c, whereby the cathode separator 4c is electrically connected to the cathode gas diffusion layer 3c. A plurality of oxidant gas supply paths 8 are formed as shown in FIG. 2 by the plurality of grooves for the oxidant gas supply path in the central portion 4 cm and the cathode gas diffusion layer 3c. The oxidant gas supplied from the plurality of oxidant gas supply paths 8 is supplied to the membrane electrode assembly 5 through the cathode gas diffusion layer 3c.

  On the other hand, the peripheral portion 4ae of the anode separator 4a is fixed to the other side surface of the support frame body 20 of the support frame 2 with an adhesive layer 13a having thermoplasticity or thermosetting property. A central portion 4am inside the peripheral edge portion 4ae of the anode separator 4a contacts the anode gas diffusion layer 3a, whereby the anode separator 4a is electrically connected to the anode gas diffusion layer 3a. As shown in FIG. 2, a plurality of fuel gas supply passages 7 are formed by the plurality of grooves for the fuel gas supply passages in the central portion 4am and the anode gas diffusion layer 3a. The fuel gas supplied from the plurality of fuel gas supply paths 7 is supplied to the membrane electrode assembly 5 through the anode gas diffusion layer 3a.

  In two adjacent fuel cell single cells 1, the cathode separator 4 c of one fuel cell single cell 1 and the anode separator 4 a of the other fuel cell single cell 1 are in contact via a seal member 14. As a result, a cooling water supply path (not shown) surrounded by the two oxidant gas supply paths 8 and the two fuel gas supply paths 7 is formed.

The cathode separator 4c and the anode separator 4a are made of a conductive material that does not transmit oxidant gas, fuel gas, and cooling water. Examples of the material of the cathode separator 4c and the anode separator 4a include metals such as stainless steel and titanium. In the embodiment shown in FIG. 2, titanium is used as the material of the cathode separator 4c and the anode separator 4a. The typical linear expansion coefficient of these materials is, for example, about 10 × 10 ⁻⁶ / ° C.

  The linear expansion coefficient of the support frame 2 is very large compared to the linear expansion coefficients of the cathode separator 4c and the anode separator 4a. Therefore, in the cooling process after heating the adhesive layers 13c and 13a to bond the separators 4c and 4a and the support frame 2, or during the cold operation of the single fuel cell 1, the support frame 2 contracts. The amount can be much greater than the shrinkage of the separators 4c, 4a. That is, there can be a large difference in the amount of shrinkage. Here, in the embodiment of FIG. 2, since the support frame body 20 is fixed to the separators 4c and 4a by the adhesive layers 13c and 13a, the amount of contraction does not increase. On the other hand, since the protrusion 21 is not bonded to the separators 4c and 4a, it tends to shrink. Here, if the Young's modulus of the material forming the protruding portion 21 is made large, for example, the same as the Young's modulus of the support frame body 20, the protruding portion 21 is difficult to elastically deform against tensile stress. Almost no expansion occurs, and the amount of contraction of the protrusion 21 increases. Therefore, a large tensile stress is generated in the adhesive layer 10 and the membrane electrode assembly 5. As a result, cracks in the adhesive layer 10 and damage to the membrane electrode assembly 5 may occur, which may cause cross leakage.

  Therefore, in the support frame 2 of the present embodiment, the Young's modulus of the material forming the protruding portion 21 is small, for example, smaller than the Young's modulus of the support frame main body 20. Thereby, since the protrusion part 21 is easy to elastically deform with respect to a tensile stress, the protrusion part 21 expand | extends and the contraction amount of the protrusion part 21 becomes small. Therefore, the tensile stress of the adhesive layer 10 and the membrane electrode assembly 5 is reduced. As a result, cracks in the adhesive layer 10, damage to the membrane electrode assembly 5, and the like are suppressed, and cross leakage is suppressed.

  Next, the manufacturing method of a fuel cell single cell is demonstrated. 5 to 9 are partial cross-sectional views showing the respective steps of the method for manufacturing the fuel cell single cell 1.

  First, as shown in FIG. 5, a membrane electrode assembly 5 in which the anode gas diffusion layer 3a is disposed on the other side surface 51 and the one side surface 52 is exposed is prepared. The anode gas diffusion layer 3a and the membrane electrode assembly 5 are heated and compressed by, for example, a hot press process and bonded in advance.

  Next, as shown in FIG. 6, the cathode gas diffusion layer 3 c is disposed so that the outer peripheral edge 52 e remains on one side 52 of the membrane electrode assembly 5. Thereafter, the cathode gas diffusion layer 3c and the membrane electrode assembly 5 are joined by being heated and compressed by, for example, a hot press process.

  Next, as shown in FIG. 7, the adhesive layer 10 having ultraviolet curability is formed on the outer peripheral edge portion 52e. In the embodiment shown in FIG. 7, as the material for the adhesive layer 10, a UV curable adhesive using a radical polymerizable resin is used. Further, the adhesive layer 10 is formed on the entire outer peripheral edge portion 52e. As a method of forming the adhesive layer 10, a method of applying a UV curable adhesive on the outer peripheral edge 52e by screen printing is used. In another embodiment (not shown), the adhesive layer 10 is first formed on one side surface 52 of the membrane electrode assembly 5, and then the cathode gas diffusion layer 3c is formed.

  Subsequently, as shown in FIG. 8, the support frame 2 shown in FIG. 3 is prepared. In the embodiment shown in FIG. 8, a polypropylene resin is used as the material of the support frame body 20, and ethylene-propylene rubber (EPDM, EPM) is mixed in polypropylene as the material of the projecting portion 21 and the joint portion 22. Elastomer is used. Subsequently, the support frame 2 is disposed on the adhesive layer 10. In the embodiment shown in FIG. 8, the protruding portion 21 of the support frame 2 is disposed on the adhesive layer 10. As a result, the protruding portion 21 of the support frame 2 comes into contact with the outer portion 32 of the adhesive layer 10 and the inner portion 31 of the adhesive layer 10 is exposed. Thereby, the support frame 2 is adhered to the adhesive layer 10.

  Thereafter, the adhesive layer 10 is irradiated with ultraviolet rays UV having a predetermined wavelength (for example, 365 nm) while pressing the support frame 2 in a direction from the one side surface 52 side to the other side surface 51 side of the membrane electrode assembly 5. Here, since the protruding portion 21 is a polypropylene-based resin, ultraviolet rays UV having a predetermined wavelength can be transmitted. Therefore, the adhesive layer 10 is cured by receiving ultraviolet rays. Irradiation conditions (eg, the amount of ultraviolet light, irradiation time, etc.) are appropriately selected depending on the material of the adhesive layer 10. As a result, the adhesive layer 10 adheres to the membrane electrode assembly 5, thereby adhering the support frame 2 and the membrane electrode assembly 5.

  Thereafter, as shown in FIG. 9, the peripheral portion 4ce of the cathode separator 4c and the peripheral portion 4ae of the anode separator 4a are arranged on the support frame 2 via the adhesive layers 13c and 13a, respectively. Then, the adhesive layers 13c and 13a are heated, melted, cooled and cured, and the peripheral portion 4ce of the cathode separator 4c and the peripheral portion 4ae of the anode separator 4a are bonded to the support frame 2. Thereby, the membrane electrode assembly 5 having the gas diffusion layers 3c and 3a and the support frame 2 are sandwiched between the separators 4c and 4a. In this way, the membrane electrode assembly 5, the gas diffusion layers 3c and 3a, the support frame 2, and the separators 4c and 4a are integrated.

  The fuel cell single cell 1 is formed by the above steps.

  Next, a support frame 2 according to another embodiment will be described with reference to FIG. In the support frame 2, the side surface 22 s 5 and the end surface 22 s 6 of the joint portion 22 are joined to the support frame body 20 so as to be covered by the support frame body 20. Therefore, the joint portion 22 is joined to the support frame main body 20 on the two surfaces 22s5 and 22s6. The thickness of the protruding portion 21 is substantially the same as or slightly thinner than the thickness of the joint portion 22. In this case, since it is not necessary to form the support frame main body 20 so as to surround the joint portion 22, it is easier to form the support frame 2 than in the case of FIG. 3.

  Next, a support frame 2 of still another embodiment will be described with reference to FIG. In the support frame 2, the end surface 22 s 7 of the joint portion 22 is joined to the support frame body 20 so as to be in contact with the support frame body 20. The thickness of the protruding portion 21 is smaller than the thickness of the joint portion 22. In this case, since it is not necessary to form the support frame main body 20 so as to surround the joint portion 22, it is easier to form the support frame 2 than in the case of FIG. 3.

  In each of the above embodiments, one side surface 52 of the membrane electrode assembly 5 is a cathode electrode side surface, and the other side surface 51 is an anode electrode side surface. In still another embodiment (not shown), one side surface of the membrane electrode assembly 5 is the anode electrode side surface, and the other side surface is the cathode electrode side surface.

DESCRIPTION OF SYMBOLS 1 Fuel cell single cell 2 Support frame 3a Anode gas diffusion layer 3c Cathode gas diffusion layer 4a Anode separator 4c Cathode separator 5 Membrane electrode assembly 10 Adhesive layer 20 Support frame main body 21 Projection part 22 Joining part 51 Other side surface (Membrane electrode joining) body)
52 One side (membrane electrode assembly)
52e outer peripheral edge

Claims (4)

A membrane electrode assembly in which electrode catalyst layers are respectively formed on both side surfaces of the electrolyte membrane;
Gas diffusion layers respectively disposed on both side surfaces of the membrane electrode assembly while leaving an outer peripheral edge on one side surface of the membrane electrode assembly,
A first adhesive layer formed on the outer peripheral edge;
A support frame fixed on the outer peripheral edge by the first adhesive layer ;
A second adhesive layer formed on the support frame;
Separators fixed on the support frame by the second adhesive layer at a peripheral portion and respectively disposed on both sides of the support frame and the gas diffusion layer so as to contact the gas diffusion layer at a central portion; ,
With
The support frame is
A support frame body in which the separators are fixed by the second adhesive layer,
A projecting portion joined to an inner edge portion of the support frame body through a joining portion so as to extend from an inner edge portion of the support frame body to an inner side of the support frame body, and is formed on the first adhesive layer A protrusion that is fixed to the outer peripheral edge and is thinner than the support frame body;
Including
In the plane direction parallel to the side surface of the membrane electrode assembly, the first adhesive layer is disposed closer to the membrane electrode assembly than the second adhesive layer,
The protrusion is not bonded to the separator,
The Young's modulus of the material forming the protruding portion is lower than the Young's modulus of the material forming the support frame body,
Fuel cell single cell. The joining portion is joined to the support frame body on two or more surfaces;
The fuel cell single cell according to claim 1. The joint portion is joined to the support frame main body on three surfaces.
The fuel cell single cell according to claim 2. The joint area between the joint portion and the support frame main body is larger than the cross-sectional area in the thickness direction of the protrusion,
The fuel cell single cell according to any one of claims 1 to 3.

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