JP2016162648A - Manufacturing method for fuel battery single cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a fuel battery single cell that can suppress occurrence of cracks in an adhesive layer or a membrane electrode assembly below the adhesive layer.SOLUTION: A method for manufacturing a fuel battery single cell 1 having a membrane electrode assembly 5, gas diffusion layers 3c, 3a, a support frame 2 and separators 4c, 4a comprises a step of preparing the membrane electrode assembly having the gas diffusion layers arranged on both side surfaces 51 and 52 while leaving an outer peripheral edge portion 52e on the one side surface 52 of the membrane electrode assembly, and forming the adhesive layer 10 on the outer periphery edge portion, a step of arranging a support frame on the adhesive layer and sectioning, on the support frame, an inner portion 2e overlapped with the membrane electrode assembly and an outer portion 2f which surrounds the inner portion while protruding to the outside of the membrane electrode assembly, a step of curing the adhesive layer while maintaining the support frame in such a curved shape that a portion of the outer portion extends beyond a reference plane RS containing one side surface of the membrane electrode assembly to the other side of the membrane electrode assembly with the inner portion being in contact with the adhesive layer, and a step of fixing the separators on both the side surfaces of the support frame while flattening the support frame.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method for manufacturing a fuel cell single cell.

  A membrane electrode assembly in which an electrode catalyst layer is formed on both sides of the electrolyte membrane, a gas diffusion layer disposed on each side surface of the membrane electrode assembly, and a membrane electrode assembly supported on the outer periphery of the membrane electrode assembly A support frame, a membrane electrode assembly in which a gas diffusion layer is disposed, and a separator that is disposed on each side surface of the support frame, is fixed to the support frame at the peripheral portion, and is in contact with the gas diffusion layer at the central portion. A fuel cell single cell manufacturing method comprising a membrane electrode assembly in which a gas diffusion layer is disposed on each side surface while leaving an outer peripheral edge on one side surface of the membrane electrode assembly. Forming an adhesive layer on the inner portion of the support frame having an outer portion and an inner portion protruding inwardly from the outer portion; and the adhesive layer on one side of the membrane electrode assembly of A step of disposing the support frame on the membrane electrode assembly so as to overlap the peripheral portion, a step of curing the adhesive layer, and a step of fixing the peripheral portions of the separator on both side surfaces of the outer peripheral portion of the support frame, There is known a method for manufacturing a fuel cell single cell comprising (see, for example, Patent Document 1).

JP 2014-137936 A

  The adhesive layer between the membrane electrode assembly having gas diffusion layers on both sides and the support frame shrinks when cured. Therefore, as the support frame on the adhesive layer shrinks, the portion that does not overlap with the outer peripheral edge of the support frame curves from the other side of the membrane electrode assembly to the one side. When the separator is bonded to both side surfaces of the support frame in a state where the support frame is curved to one side surface of the membrane electrode assembly, the support frame becomes straight following the shape of the separator, and the adhesive in the support frame The portion that is not bonded to the layer is pushed from one side surface of the membrane electrode assembly to the other side surface by the separator. At this time, the adhesive layer is pulled in the direction from the other side surface side to the one side surface side of the membrane electrode assembly, that is, the direction in which the adhesive layer is peeled off. When the fuel cell unit cell is placed in a low-temperature environment when the fuel cell unit cell is used, for example, in the case of cold operation, if the support frame contracts, the force with which the support frame pulls the adhesive layer becomes greater. Therefore, the tensile force may cause a crack in the adhesive layer or the membrane electrode assembly below the adhesive layer. A technique for suppressing the occurrence of cracks in the adhesive layer or the membrane electrode assembly below the adhesive layer is desired.

  According to the present invention, a membrane electrode assembly in which an electrode catalyst layer is formed on each side of an electrolyte membrane, a gas diffusion layer disposed on each side surface of the membrane electrode assembly, and the membrane electrode assembly A support frame that supports the membrane electrode assembly on the outer periphery, the membrane electrode assembly on which the gas diffusion layer is disposed, and each side surface of the support frame, and is fixed to the support frame at a peripheral portion, A separator for contacting the gas diffusion layer at a central portion, and a method for producing a single cell of a fuel cell, on both sides while leaving an outer peripheral edge on one side of the membrane electrode assembly A step of preparing the membrane electrode assembly in which the gas diffusion layer is disposed, a step of forming an adhesive layer on an outer peripheral edge on one side surface of the membrane electrode assembly, and the support frame. Previous Arranged on the adhesive layer, the support frame is divided into an inner portion overlapping the membrane electrode assembly and an outer portion surrounding the inner portion while projecting outward from the membrane electrode assembly. And the membrane beyond the reference plane including at least one part of the outer part of the support frame including one side of the membrane electrode assembly while the inner part of the support frame is in contact with the adhesive layer The step of curing the adhesive layer while maintaining the support frame in a curved shape extending toward the other side of the electrode assembly, and on both sides of the outer peripheral edge of the support frame while flattening the support frame And a step of fixing each of the peripheral portions of the separator.

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

It is a fragmentary sectional view which shows the structural example of a fuel cell single cell. It is the elements on larger scale of FIG. It is sectional drawing which shows the state of a support frame when the separator in a fuel cell single cell is not assembled | attached. 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 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 the fuel cell single cell of a comparative example. It is a fragmentary sectional view which shows the process of the manufacturing method of the fuel cell single cell of a comparative example. It is a fragmentary sectional view which shows the process of the manufacturing method of the fuel cell single cell of a comparative example. It is a fragmentary sectional view which shows the process of the manufacturing method of the fuel cell single cell of another Example. It is a fragmentary sectional view which shows the process of the manufacturing method of the fuel cell single cell of another Example.

  FIG. 1 is a partial cross-sectional view showing a configuration example of a fuel cell single cell 1, and FIG. 2 is a partially enlarged view thereof. The fuel cell stack A is formed by a stacked body in which a plurality of the single fuel cell 1 shown in FIG. 1 is stacked in the thickness direction S of the single fuel 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 supplied to the fuel cell via a plurality of wires (not shown) extending from the terminal plates (not shown) arranged at both ends of the laminate to the outside of the fuel cell stack A. It is taken out of the stack A. The electric power taken out from the fuel cell stack A is supplied to, for example, an electric motor for driving an electric vehicle or a capacitor.

  The single fuel cell 1 includes a membrane electrode assembly 5. The membrane electrode assembly 5 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 membrane electrode assembly 5 side of the porous body.

  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. FIG. 2 shows a case where the single fuel cell 1 is at a normal temperature (for example, 20 ° C.). In this case, the adhesive layer 10 has a direction P that connects the support frame 2 and the cathode gas diffusion layer 3c to each other. Compressive stress is generated. 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. In the embodiment shown in FIG. 2, the support frame 2 has an inner portion 2e that overlaps with the membrane electrode assembly 5 and an outer portion 2f that protrudes outward from the membrane electrode assembly 5 and surrounds the inner portion 2e. ing. The inner portion 2 e 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 inner part 2e is bonded to the outer peripheral edge 52e of the membrane electrode assembly 5, a gap G is formed between the inner part 2e and the outer part 3ce of the cathode gas diffusion layer 3c. That is, the support frame 2 is disposed apart from the cathode gas diffusion layer 3c.

The support frame 2 is formed of a material having electrical insulation and airtightness. Examples of the material of the support frame 2 include resin plates such as polypropylene resin, phenol resin, epoxy resin, polyethylene terephthalate resin, and polyethylene naphthalate resin. In the embodiment shown in FIG. 2, as the material of the support frame 2, 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. The typical linear expansion coefficient of these materials is, for example, about 100 × 10 ⁻⁶ / ° C.

  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 the other side surface 20sc of the support frame 2 with an adhesive (not shown) 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. The central portion 4 cm of the cathode separator 4 c is provided with a plurality of grooves for an oxidant gas supply path, and a plurality of oxidant gas supply paths 8 are formed by these grooves and the cathode gas diffusion layer 3 c as shown in FIG. It is formed. 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 one side surface 20sa of the support frame 2 with an adhesive (not shown) 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. The central portion 4am of the anode separator 4a is provided with a plurality of grooves for fuel gas supply paths, and a plurality of fuel gas supply paths 7 are formed by these grooves and the anode gas diffusion layer 3a as shown in FIG. The 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 4c of one fuel cell single cell 1 and the anode separator 4a of the other fuel cell single cell 1 are in contact with each other via a seal member (not shown). 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. 1, 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 layer 10 to bond the separators 4c, 4a and the support frame 2, or during the cold operation of the single fuel cell 1, the shrinkage amount of the support frame 2 is This is much larger than the shrinkage amount of the separators 4c and 4a. If this happens, a large tensile stress is generated in the adhesive layer 10 and the membrane electrode assembly 5 due to the shrinkage of the support frame 2, causing a crack in the adhesive layer 10, damage to the membrane electrode assembly 5, and the like. There is a risk of becoming.

  Therefore, in this embodiment, as shown in FIG. 3, the cathode separator 4c and the anode separator 4a are assembled on both sides of the membrane electrode assembly 5 and the support frame 2 having the cathode gas diffusion layer 3c and the anode gas diffusion layer 3a. When not, the support frame 2 has a curved shape. That is, the support frame 2 has the inner portion 2e fixed to the adhesive layer 10 and at least a part of the outer portion 2f exceeds the reference plane RS including one side surface 52 of the membrane electrode assembly 5 and It has a curved shape extending toward the other side surface 51. This curved shape is provided in order to make the above-described compressive stress inherent in the adhesive layer 10 after the fuel cell unit cell 1 is assembled. In the embodiment shown in FIG. 3, the support frame 2 has a curved shape in which at least the distal end portion of the outer portion 2f extends toward the other side surface 51 of the membrane electrode assembly 5 beyond the reference plane RS. The frame 2 is curved so as to form a concave surface on one side contacting the adhesive layer 10.

  When the fuel cell unit cell 1 is formed, the support frame 2 having a curved shape is sandwiched between the separators 4c and 4a together with the membrane electrode assembly 5 including the gas diffusion layers 3c and 3a as shown in FIG. Shape. At that time, since the inner portion 2e of the support frame 2 in contact with the adhesive layer 10 pushes the adhesive layer 10, particularly the adhesive layer 10 in the gap G, toward the cathode gas diffusion layer 3c, the adhesive layer 10 is supported by the support frame. 2 is sandwiched between the inner part 2e of the 2 and the outer part 3ce of the cathode gas diffusion layer 3c and compressed. That is, compressive stress is generated in the adhesive layer 10. Such a compressive stress is caused by the shrinkage of the support frame 2 during the cooling process after heating when the separators 4c and 4a are bonded to the support frame 2, or during the cold operation of the fuel cell unit cell 1, and the adhesive layer. 10 and the tensile stress generated in the membrane electrode assembly 5 can be relaxed. Thereby, destruction of the adhesive layer 10 can be suppressed, and damage to the membrane electrode assembly 5 can be suppressed.

  Next, the manufacturing method of a fuel cell single cell is demonstrated. 4-11 is a fragmentary sectional view which shows each process of the manufacturing method of the fuel cell single cell 1. FIG.

  First, as shown in FIG. 4, 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. 5, the cathode gas diffusion layer 3 c is disposed so that the outer peripheral edge portion 52 e remains on one side surface 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. 6, the adhesive layer 10 having ultraviolet curability is formed on the outer peripheral edge portion 52e. In the embodiment shown in FIG. 6, a UV curable adhesive using a radical polymerizable resin is used as the material of the adhesive layer 10. 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), a thermosetting adhesive is used as the material of the adhesive layer 10. In still 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. 7, a flat frame-like support frame 2 is prepared. In the embodiment shown in FIG. 7, a polypropylene resin is used as the material of the support frame 2. Subsequently, the support frame 2 is disposed on the adhesive layer 10. In the embodiment shown in FIG. 7, by disposing the support frame 2 on the adhesive layer 10, the support frame 2 has an inner portion 2 e that overlaps the membrane electrode assembly 5 and an outer side than the membrane electrode assembly 5. And an outer portion 2f surrounding the inner portion 2e. As a result, the inner portion 2e of the support frame 2 contacts 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, as shown in FIG. 8, the membrane electrode assembly 5 in which the support frame 2 and the gas diffusion layers 3 c and 3 a are arranged is arranged on a flat plate base 62. On the support frame 2, a substantially flat frame-shaped pressing member 61 is disposed facing each other. The pressing member 61 is formed in a size capable of simultaneously contacting the inner portion 2e and the outer portion 2f of the support frame 2, and includes an inner portion 61e for applying a load to the inner portion 2e of the support frame 2, and a support And an outer portion 61 f for applying a load to the outer portion 2 f of the frame 2. Here, one side surface 61sa of the pressing member 61 that contacts the support frame 2 has a step 61k at the boundary between the outer portion 61f and the inner portion 61e, and the outer portion 61f of the pressing member 61 is the outer portion 2f of the supporting frame 2. A slight gap D is formed between the inner portion 61e of the pressing member 61 and the inner portion 2e of the support frame 2 when the pressure member 61 abuts against the inner surface 2e. At this time, the position of the step 61k is outside of the anode gas diffusion layer 3a in the planar direction.

  Subsequently, as illustrated in FIG. 9, a load in a direction toward the adhesive layer 10 is applied to the inner portion 2 e of the support frame 2 by the inner portion 61 e of the pressing member 61 so that the support frame 2 is deformed into a curved shape. At the same time, a load in a direction from one side surface 52 to the other side surface 51 of the membrane electrode assembly 5 is applied to the outer portion 2 f of the support frame 2 by the outer portion 61 f of the pressing member 61. In the embodiment shown in FIG. 9, the outer portion 61f near the step 61k applies a load to the outer portion 2f. As a result, the inner portion 2e of the support frame 2 is in contact with the adhesive layer 10 and the outer portion 2f of the support frame 2 exceeds the reference plane RS including one side surface 52 of the membrane electrode assembly 5 and the other portions of the membrane electrode assembly 5 The support frame 2 is deformed into a curved shape extending toward the side surface 51. At this time, the load applied to the outer portion 2f of the support frame 2 by the outer portion 61f is larger than the load applied to the inner portion 2e of the support frame 2 by the inner portion 61e.

  Along with the application of the load, the adhesive layer 10 is irradiated with ultraviolet rays UV having a predetermined wavelength (example: 365 nm). Here, since the pressing member 61 is made of quartz and the support frame 2 is also made of polypropylene resin, both of them can transmit ultraviolet rays UV having a predetermined wavelength. 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. In another embodiment (not shown) using an adhesive having thermosetting properties, the adhesive layer 10 and its surroundings are heated instead of irradiating the adhesive layer 10 with ultraviolet rays UV.

  Thereafter, as shown in FIG. 10, the membrane electrode assembly 5 in which the support frame 2 and the gas diffusion layers 3 c and 3 a are arranged is removed from the pressing member 61 and the pedestal 62. At this time, the support frame 2 is maintained in a curved shape as shown in FIG. When the pressing member 61 is removed, the support frame 2 may be slightly deformed to return to the original flat shape, and in this case, the degree of bending is slightly relaxed.

  Next, as shown in FIG. 11, the cathode separator 4 c is disposed on the support frame 2 via an adhesive so that the peripheral portion 4 ce of the cathode separator 4 c is in contact with the other side surface 20 sc of the support frame 2. At the same time, the anode separator 4a is disposed on the support frame 2 via an adhesive so that the peripheral portion 4ae of the anode separator 4a is in contact with one side surface 20sa of the support frame 2. At this time, the curved support frame 2 is sandwiched between the separators 4c and 4a and becomes flat. Therefore, since the inner portion 2e of the support frame 2 pushes the adhesive layer 10 toward the cathode gas diffusion layer 3c, the adhesive layer 10 can be in a state where compression stress is inherent. Then, the adhesive between the separators 4c and 4a and the support frame 2 is 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 and the support frame 2 are bonded. . 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. At that time, the adhesive layer 10 which is made flat and has compressive stress maintains the state in which compressive stress is inherent. 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.

  Here, in order to explain the effect of the above manufacturing method (hereinafter referred to as “manufacturing method of the example”), a typical manufacturing method (hereinafter referred to as “comparative example”) different from the manufacturing method of the above example. The manufacturing method will be described with reference to FIGS.

  In the manufacturing method of the comparative example, first, the cathode gas diffusion layer 103c and the anode gas diffusion layer 103a are arranged on both side surfaces 152 and 151 by the same steps as the steps of FIGS. In the membrane electrode assembly 105, the adhesive layer 110 is formed on the outer peripheral edge 152 e, and the support frame 102 is disposed on the adhesive layer 110.

  Next, as shown in FIG. 12, the membrane electrode assembly 105 in which the support frame 102 and the gas diffusion layers 103 c and 103 a are arranged is arranged on a flat plate 162. On the support frame 102, a flat plate frame-shaped pressing member 161 having no step is disposed facing each other. Subsequently, UV light having a predetermined wavelength is applied to the adhesive layer 110 while applying a load in a direction from the one side surface 152 of the membrane electrode assembly 5 to the other side surface 151 of the membrane electrode assembly 5 by the pressing member 161. Irradiate to cure the adhesive layer 110. Thereby, the support frame 102 and the membrane electrode assembly 105 are bonded. At this time, the adhesive layer 110 is cured while the support frame 102 is maintained in a state substantially parallel to the membrane electrode assembly 105. As a result, shrinkage stress is inherent in the surface of the adhesive layer 110, particularly the adhesive layer 110.

  Thereafter, as shown in FIG. 13, the membrane electrode assembly 105 in which the support frame 102 and the gas diffusion layers 103 c and 103 a are arranged is removed from the pressing member 161 and the pedestal 162. As a result, the support frame 102 bends toward the side surface 152 of the membrane electrode assembly 105 due to the shrinkage stress inherent in the adhesive layer 110. That is, it curves to the opposite side to the case of the process of FIG.

  Next, as shown in FIG. 14, the cathode separator 104 c and the anode separator 104 a are arranged on both side surfaces of the membrane electrode assembly 105 having the cathode gas diffusion layer 103 c and the anode gas diffusion layer 103 a and the support frame 2. At this time, the curved support frame 102 is sandwiched between the separators 104c and 104a and becomes flat. Therefore, the inner portion 102e of the support frame 102 pulls the adhesive layer 110 toward the inner portion 102e of the support frame 102, and tensile stress is generated in the adhesive layer 110. Thereafter, the peripheral portion 104ce of the cathode separator 104c and the other side surface 120sc of the support frame 102 are bonded with an adhesive, and the peripheral portion 104ae of the anode separator 104a and one side surface 120sa of the support frame 102 are bonded with an adhesive. At this time, the tensile stress inherent in the adhesive layer 110 increases in the cooling process after heating the adhesive. The same applies to the subsequent cold operation.

  Therefore, in the manufacturing method of the comparative example, tensile stress is generated in the adhesive layer 110 when the separators 104c and 104a are arranged, and in the cooling process after heating when the separators 104c and 104a are bonded to the support frame 102, or During the cold operation, the tensile stress inherent in the adhesive layer 110 increases, so that the adhesive layer 110 is easily cracked. Therefore, in the manufacturing method of the comparative example, the adhesive layer 110 is easily cracked, the membrane electrode assembly 105 is easily damaged, and cross leaks are likely to occur.

  On the other hand, in the manufacturing method of the embodiment, as described together with the steps of FIGS. 4 to 11, the support frame 2 is curved on the membrane electrode assembly 5 so as to bend toward the other side 51 of the membrane electrode assembly 5. The adhesive layer 10 is cured while being fixed by the adhesive layer 10. Therefore, when the support frame 2 is sandwiched between the separators 4c and 4a and is in a flat state, the adhesive layer 10 is compressed in the direction of the cathode gas diffusion layer 3c and is in a state where compression stress is inherent. Such compressive stress can relieve the tensile stress generated in the adhesive layer 10 and the membrane electrode assembly 5 during the subsequent process or use. Thereby, the crack in the adhesive bond layer 10 can be suppressed, and the damage of the membrane electrode assembly 5 can be suppressed. In other words, considering the difference from the manufacturing method of the comparative example, when the support frame 2 is sandwiched between the separators 4c and 4a and is in a flat state, there is a state in which compressive stress is generated in the adhesive layer 10. is necessary. Even in the manufacturing method of the embodiment, when the adhesive layer 10 is cured while the support frame 2 is curved, the shrinkage stress is inherent in the adhesive layer 10. Next, when the pressing member 61 is removed, the degree of curvature of the support frame is slightly relieved by the shrinkage stress of the adhesive layer 10.

  Next, another embodiment of the manufacturing method will be described with reference to FIGS. In the manufacturing method of this another embodiment, the configuration of the pressing member used in the step of bending the support frame 2 is different from the manufacturing method of the embodiment shown in FIGS. The differences will be mainly described below.

  In the manufacturing method of this another embodiment, first, the cathode gas diffusion layer 3c and the anode gas diffusion layer 3a are formed on the both side surfaces 52 and 51 of the membrane electrode assembly 5 by the same process as the process of FIGS. The adhesive layer 10 is formed on the outer peripheral edge 52 e of the membrane electrode assembly 5, and the support frame 2 is disposed on the adhesive layer 10.

  Next, as shown in FIG. 15, the membrane electrode assembly 5 in which the support frame 2 is disposed on the adhesive layer 10 and the gas diffusion layers 3 c and 3 a are disposed on both side surfaces 52 and 51 is placed on the pedestal 62. Deploy. In addition, a flat frame-shaped pressing member 61 a is disposed on the inner portion 2 e of the support frame 2. The load in the direction toward the adhesive layer 10 is applied to the inner portion 2e of the support frame 2 by the pressing member 61a without applying a load to the outer portion 2f of the support frame. At this time, the support frame 2 is not deformed into a curved state. At the same time, the adhesive layer 10 is incompletely cured by irradiating the adhesive layer 10 with ultraviolet rays UV having a predetermined wavelength (example: 365 nm). That is, the adhesive layer 10 is not completely cured, and when the support frame 2 is curved in a subsequent process, the adhesive layer 10 is cured to such an extent that the inner portion 2e can be held without being peeled off from the outer peripheral edge 52e. Irradiation conditions (eg, the amount of ultraviolet light, irradiation time, etc.) are appropriately selected depending on the material of the adhesive layer 10.

  Thereafter, as shown in FIG. 16, the pressing member 61 a is removed, and the flat plate-shaped pressing member 61 b is disposed on the outer portion 2 f of the support frame 2. Then, the load in the direction from the one side surface 52 to the other side surface 51 of the membrane electrode assembly 5 is applied to the outer portion 2 f of the support frame 2 by the pressing member 61 b without applying a load to the inner portion 2 e of the support frame 2. As a result, the support frame 2 is deformed into a curved shape. At the same time, the adhesive layer 10 is completely cured by irradiating the adhesive layer 10 with ultraviolet rays UV having a predetermined wavelength (example: 365 nm). Irradiation conditions (eg, the amount of ultraviolet light, irradiation time, etc.) are appropriately selected depending on the material of the adhesive layer 10.

  Subsequently, the cathode separator 4c and the anode separator 4a are fixed to the both side surfaces 20sc and 20sa of the support frame 2 by a process similar to the process of FIG.

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

  Also in this case, the same effects as those of the manufacturing method of the embodiment shown in FIGS. 4 to 11 can be obtained. Moreover, the structure of the pressing member can be simplified.

  In the embodiment of FIGS. 4 to 11 and the embodiment of FIGS. 15 to 16, the initially flat support frame 2 is deformed into a curved shape in the middle of the process. In still another embodiment (not shown), the support frame 2 having the curved shape is used from the beginning. In that case, in the step of placing the support frame 2 on the adhesive layer 10 (step shown in FIG. 7), the support frame 2 is placed on the adhesive layer 10 so that the support frame 2 takes a curved shape.

  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 2e Inner part 2f Outer part 3a Anode gas diffusion layer 3c Cathode gas diffusion layer 5 Membrane electrode assembly 10 Adhesive layer 51 Other side surface (membrane electrode assembly)
52 One side (membrane electrode assembly)
52e Outer peripheral edge RS Reference plane

Claims (5)

A membrane electrode assembly in which electrode catalyst layers are respectively formed on both sides of the electrolyte membrane; a gas diffusion layer disposed on each side surface of the membrane electrode assembly; and the membrane electrode junction on the outer periphery of the membrane electrode assembly A support frame for supporting the body, the membrane electrode assembly on which the gas diffusion layer is disposed, and both sides of the support frame, fixed to the support frame at a peripheral portion, and the gas diffusion at a central portion A separator that contacts the layer, and a method of manufacturing a fuel cell single cell comprising:
Preparing the membrane electrode assembly in which the gas diffusion layers are respectively disposed on both side surfaces while leaving an outer peripheral edge on one side surface of the membrane electrode assembly; and
Forming an adhesive layer on the outer peripheral edge on one side of the membrane electrode assembly;
The support frame is disposed on the adhesive layer, thereby enclosing the inner portion of the support frame overlapping the membrane electrode assembly and the inner portion while projecting outward from the membrane electrode assembly. A step in which the outer portion is partitioned;
While the inner portion of the support frame is in contact with the adhesive layer, at least a part of the outer portion of the support frame exceeds a reference plane including one side surface of the membrane electrode assembly, and the other side surface of the membrane electrode assembly. Curing the adhesive layer while maintaining the support frame in a curved shape extending toward
Fixing each of the peripheral portions of the separator on both side surfaces of an outer peripheral edge of the support frame while flattening the support frame;
Comprising
A method for producing a single fuel cell. Prior to the step of curing the adhesive layer, the support frame has a flat shape,
The step of curing the adhesive layer includes:
While applying a load in a direction from one side surface of the membrane electrode assembly to the other side surface of the membrane electrode assembly on the outer portion of the support frame so that the support frame is deformed into the curved shape, A step of curing the adhesive layer,
The manufacturing method of the fuel cell single cell of Claim 1. The pressing member is formed in a size capable of simultaneously contacting the inner part and the outer part of the support frame,
The step of curing the adhesive layer while applying a load with the pressing member,
At the portion of the pressing member that contacts the inner portion of the support frame, a load in the direction toward the adhesive layer is applied to the inner portion of the support frame, and at the same time, the portion of the pressing member that contacts the outer portion of the support frame. Curing the adhesive layer while applying the load to an outer portion of a support frame,
The manufacturing method of the fuel cell single cell of Claim 2. Without applying a load to the outer part of the support frame, the adhesive layer is cured incompletely while applying a load in a direction toward the adhesive layer to the inner part of the support frame with another pressing member. Further comprising a process,
The step of curing the adhesive layer while applying a load with the pressing member,
Without applying a load to the inner portion of the support frame after the adhesive layer has been incompletely cured, the pressure member completely applies the load to the outer portion of the support frame while applying the load to the outer portion of the support frame. A curing step;
including,
The manufacturing method of the fuel cell single cell of Claim 2. The support frame has a curved shape before being placed on the adhesive layer, and the step of placing the support frame on the adhesive layer causes the support frame to take the curved shape. The support frame is disposed on the adhesive layer;
The manufacturing method of the fuel cell single cell of Claim 1.

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