JP2021093243A - Fuel cell module and fuel cell stack, and manufacturing method of fuel cell module - Google Patents

Abstract

To provide a fuel cell module enabling the power generation performance thereof to be improved.SOLUTION: A fuel cell module comprises: a film-electrode joined body having a polymer electrolyte membrane, an anode electrode provided in a first principal plane of the polymer electrolyte membrane and a cathode electrode provided in a second principal plane of the polymer electrolyte membrane; a pair of separators that sandwich the film-electrode joined body; and a sealing member that adheres the film-electrode joined body to the pair of separators to seal them. The sealing member includes an opening penetrated in a thickness direction on an inner side region in a surface direction inner than an external peripheral portion of the film-electrode joined body, adheres the external peripheral portion of the film-electrode joined body to the external peripheral portion of each of the pair of separators facing the film-electrode joined body, and a distance between the pair of separators on an inner edge portion of the sealing member is larger than the distance between the pair of separators on an external edge portion of the sealing member.SELECTED DRAWING: Figure 4

Description

The present disclosure relates to a fuel cell module and a fuel cell stack, and a method for manufacturing the fuel cell module.

In the fuel cell module described in Patent Document 1, a membrane-electrode assembly is sandwiched between a pair of separators, and each of the membrane-electrode assembly and the pair of separators is a resin portion containing fibers at least in part. They are glued together and joined together.

The fuel cell stack described in Patent Document 2 includes a membrane-electrode assembly having a structure in which an electrolyte membrane is sandwiched between a pair of electrode layers, and a pair of separators forming a gas flow path between the membrane-electrode assembly. It is provided with a displacement absorbing member capable of absorbing the displacement in the stacking direction in a state where the fuel cell single cells are stacked. The displacement absorbing member has conductivity and is interposed between one separator and a fuel cell single cell adjacent to each other at the time of stacking.

Japanese Patent Application No. 2016-507916 JP-A-2017-216255

However, according to the conventional fuel cell module and fuel cell stack, there is still room for improvement from the viewpoint of improving the power generation performance.

Therefore, an object of the present disclosure is to provide a fuel cell module and a fuel cell stack capable of improving power generation performance, and a method for manufacturing the fuel cell module in order to solve the above problems.

The fuel cell module of the present disclosure includes a polymer electrolyte membrane, an anode electrode provided on the first main surface of the polymer electrolyte membrane, and a cathode electrode provided on the second main surface of the polymer electrolyte membrane. A membrane-electrode assembly, a pair of separators sandwiching the membrane-electrode assembly, and a sealing member for adhering and sealing each of the membrane-electrode assembly and the pair of separators. The sealing member has an opening penetrating in the thickness direction on the inner region inside in the plane direction from the outer peripheral portion of the membrane-electrode assembly, and forms the outer peripheral portion of the membrane-electrode assembly and the membrane-electrode assembly. The outer peripheral portions of the pair of separators facing each other are adhered to each other, and the distance between the pair of separators on the inner edge portion of the sealing member is larger than the distance between the pair of separators on the outer edge portion of the sealing member.

The fuel cell stack of the present disclosure has at least two of the above-mentioned fuel cell modules, and at least two fuel cell modules are laminated and fastened.

The method for manufacturing a fuel cell module of the present disclosure includes a polymer electrolyte membrane, an anode electrode provided on the first main surface of the polymer electrolyte membrane, and a cathode electrode provided on the second main surface of the polymer electrolyte membrane. A preparatory step for preparing a membrane-electrode assembly, a pair of separators, and a sealing member, and a sealing member is arranged so as to sandwich the outer peripheral portion of the membrane-electrode assembly. It also includes an arrangement step of arranging a pair of separators so as to sandwich the sealing member, and a sealing step of sealing with a pressure larger than the inner edge of the sealing member applied to the outer edge of the sealing member.

According to the fuel cell module, the fuel cell stack, and the method for manufacturing the fuel cell module according to the present disclosure, the power generation performance can be improved.

An exploded perspective view of the fuel cell stack according to the first embodiment of the present disclosure. Top view of the membrane-electrode assembly and the sealing member of the fuel cell module according to the first embodiment of the present disclosure. A-A cross-sectional view of the membrane-electrode assembly of FIG. Partial sectional view showing the state before fastening of the fuel cell module according to the first embodiment of the present disclosure. Partial sectional view of a fuel cell stack showing a state in which the fuel cell modules according to the first embodiment of the present disclosure are laminated and fastened. Simulation result showing the relationship between the surface pressure applied to the membrane-electrode assembly according to the first embodiment of the present disclosure and the contact area between adjacent separators. An exemplary flowchart of a method for manufacturing a fuel cell module according to the first embodiment of the present disclosure. Top view of the sealing member and the membrane-electrode assembly according to the second embodiment of the present disclosure. BB line sectional view of the sealing member and the membrane-electrode assembly of FIG. Top view of the sealing member and membrane-electrode assembly of the modified example Cross-sectional view of the components of a conventional polymer electrolyte fuel cell Partial sectional view of a conventional fuel cell module

(Background to this disclosure)
The polymer electrolyte fuel cell is a device that simultaneously generates electric power and heat by electrochemically reacting a fuel gas containing hydrogen with an oxidant gas containing oxygen such as air. Hereinafter, the polymer electrolyte fuel cell will be referred to as PEFC (Polymer Electrolyte Fuel Cell). The basic configuration of PEFC is shown in the cross-sectional view of FIG. The PEFC includes a polymer electrolyte membrane 150 that selectively transports hydrogen ions, and an anode electrode 190 and a cathode electrode 200 formed on both sides of the electrolyte membrane 150.

The anode electrode 190 has an anode catalyst layer 160 formed on the first main surface 151 of the electrolyte membrane 150, and an anode gas diffusion layer 181 laminated on the anode catalyst layer 160. The cathode electrode 200 has a cathode catalyst layer 170 formed on the second main surface 152 of the electrolyte membrane 150, and a cathode gas diffusion layer 182 laminated on the cathode catalyst layer 170. The anode gas diffusion layer 181 and the cathode gas diffusion layer 182 have a breathable and electron conductive function. Hereinafter, the gas diffusion layer may be referred to as GDL (Gas Diffusion Layer).

The membrane-electrode assembly 100 is assembled by integrally joining the electrolyte membrane 150 and the electrodes 190 and 200 in this way. Hereinafter, the membrane-electrode assembly 100 may be referred to as MEA (Membrane Electrode Assembly).

A cross-sectional view of the fuel cell module 210 is shown in FIG. The anode separator 111 is provided on the anode electrode 190 (FIG. 11) side of the MEA100, and the cathode separator 112 is provided on the cathode electrode 200 (FIG. 11) side of the MEA100. The anode separator 111 and the cathode separator 112 mechanically sandwich and fix the MEA 100. As described above, the structure in which the MEA 100 is sandwiched between the pair of separators 111 and 112 is the fuel cell module (cell module) 210.

The separators 111 and 112 are members for electrically connecting adjacent fuel cell modules 210 in series with each other. A gas flow path groove 131 for supplying the reaction gas to the anode electrode 190 and carrying away the generated water and excess gas is formed in the portion of the anode separator 111 that comes into contact with the MEA 100. Similarly, a gas flow path groove 132 is formed in a portion of the cathode separator 112 that comes into contact with the MEA 100.

In order to supply the reaction gas to the gas flow path grooves 131 and 132, manifold holes are provided at the edges of the separators 111 and 112 to distribute the reaction gas. Further, the pair of separators 111, so as to surround the electrode forming portion in the MEA 100, that is, the outer periphery of the power generation region, so that the reaction gas and the like supplied to the gas flow path grooves 131 and 132 do not leak to the outside or mix with each other. A sealing member 90 is arranged between the 112.

A resin frame and an elastic seal for holding the MEA 100 are used for the sealing member 90. In this case, it is necessary to fill the gap between the resin frame and the electrolyte membrane 150 with an elastic seal, which requires high component dimensional accuracy and assembly accuracy. Therefore, as in Patent Document 1, there is known a method of realizing a thin module by using an insulating thermosetting resin as a sealing member 90.

Further, when a plurality of fuel cell modules 210 are stacked in series to form a fuel cell stack, the anode separator 111 and the cathode separator 112 of the adjacent fuel cell modules 210 come into contact with each other and are electrically connected. At this time, the contact area between the anode separator 111 and the cathode separator 112 can be reduced due to the influence of the thickness variation of the separator and the warp of the separator. As a result, the electric resistance may increase and the power generation performance may decrease.

Therefore, as in Patent Document 2, there is known a method of improving electrical resistance by installing a member capable of absorbing displacement between the anode separator 111 and the cathode separator 112.

However, when the displacement absorbing member is provided, the manufacturing process may be complicated and the manufacturing cost may increase due to the increase in the number of parts. Therefore, it is difficult to improve the electric resistance of the fuel cell stack and secure the power generation performance while reducing the manufacturing cost.

As a result of diligent studies to improve the power generation performance, the present inventors have determined that the distance between the pair of separators on the inner edge of the sealing member provided with the opening is the pair on the outer edge of the sealing member. We found a configuration that was larger than the distance between the separators. Specifically, on the outer surface of the separator, the central portion has a shape that bulges in the thickness direction from the outer peripheral portion. As a result, the portion (central portion) of the separator located on the membrane-electrode assembly is deformed at the time of fastening to become a flat (substantially flat) state, so that the separator is provided at the central portion and outside in the thickness direction of the separator. The contact area between the members can be increased. As a result, it has been found that the electric resistance can be reduced and the power generation performance can be improved.

Based on these novel findings, the present inventors have arrived at the following inventions.

According to the first aspect of the present disclosure, the polymer electrolyte membrane, the anode electrode provided on the first main surface of the polymer electrolyte membrane, and the cathode electrode provided on the second main surface of the polymer electrolyte membrane. A membrane-electrode assembly having the above, a pair of separators sandwiching the membrane-electrode assembly, a membrane-electrode assembly, and a sealing member for adhering and sealing each of the pair of separators. The sealing member has an opening penetrating in the thickness direction on the inner region inside in the plane direction from the outer peripheral portion of the membrane-electrode assembly, and the outer peripheral portion of the membrane-electrode assembly and the membrane-electrode assembly. The outer periphery of each of the pair of separators facing the body is adhered, and the distance between the pair of separators on the inner edge of the sealing member is larger than the distance between the pair of separators on the outer edge of the sealing member. Provides a large fuel cell module.

According to the second aspect of the present disclosure, there is provided the fuel cell module according to the first aspect, wherein at least one of the pair of separators is formed to bulge in the thickness direction from the outer peripheral portion to the central portion. ..

According to a third aspect of the present disclosure, at least a portion of the outer edge of the sealing member is inside the outer edge of at least one of the pair of separators when viewed from a direction perpendicular to the first main surface. The fuel cell module according to the first aspect or the second aspect which is located is provided.

According to a fourth aspect of the present disclosure, at least a portion of the outer edge of the sealing member is located inside both outer edges of the pair of separators when viewed from a direction perpendicular to the first main surface. The fuel cell module according to the third aspect is provided.

According to a fifth aspect of the present disclosure, the outer edge of the sealing member is a pair of separators at positions symmetrically arranged from the center of the sealing member when viewed from a direction perpendicular to the first main surface. The fuel cell module according to the third or fourth aspect, which is located inside the outer edge of at least one of them.

According to a sixth aspect of the present disclosure, the outer edge of the sealing member is a pair of separators at positions symmetrically arranged from the center of the sealing member when viewed from a direction perpendicular to the first main surface. A fuel cell module according to a fifth aspect, which is located inside both outer edges.

According to the seventh aspect of the present disclosure, at least two fuel cell modules according to any one of the first to sixth aspects are provided, and at least two fuel cell modules are laminated and fastened. , Provides a fuel cell stack.

According to the eighth aspect of the present disclosure, the polymer electrolyte membrane, the anode electrode provided on the first main surface of the polymer electrolyte membrane, and the cathode electrode provided on the second main surface of the polymer electrolyte membrane are provided. A preparatory step for preparing the membrane-electrode assembly, the pair of separators, and the sealing member to have, and the sealing member is arranged so as to sandwich the outer peripheral portion of the membrane-electrode assembly, and the membrane-electrode assembly and the sealing member are arranged. A fuel including an arrangement step of arranging a pair of separators so as to sandwich the sealing member and a sealing step of sealing with a pressure larger than the inner edge of the sealing member applied to the outer edge of the sealing member. A method for manufacturing a battery module is provided.

Hereinafter, embodiments according to the present disclosure will be described in detail with reference to the drawings. The present disclosure is not limited by this embodiment. In addition, the dimensions of each member in the drawing do not indicate the actual dimensions, and include a part emphasized for explanation.

(Embodiment 1)
FIG. 1 is an exploded perspective view of the fuel cell stack 1 according to the first embodiment. FIG. 2 is a plan view of the membrane-electrode assembly 10 and the sealing member (gasket) 9 in the fuel cell module 2 according to the present embodiment. FIG. 3 is a sectional view taken along line AA of the membrane-electrode assembly 10 of FIG. FIG. 1 shows a state in which one fuel cell module 2 is disassembled and another fuel cell module is laminated.

[overall structure]
The fuel cell stack 1 according to the present embodiment is, for example, a polymer electrolyte fuel cell (PEFC). PEFC generates electric power, heat, and water at the same time by electrochemically reacting a fuel gas containing hydrogen with an oxidant gas containing oxygen such as air.

As shown in FIG. 1, the fuel cell stack 1 includes, for example, a fuel cell module (fuel cell) 2 which is a cell cell module, a current collector plate 3, an end plate 4, and a spring 5. In the fuel cell stack 1, a plurality of fuel cell modules 2 are stacked so as to be connected in series. At both ends of the fuel cell stack 1, an end plate 4 and a current collector plate 3 arranged inside the end plate 4 are arranged. A plurality of springs 5 are arranged on the inner surface of the end plate 4, that is, the surface on the fuel cell module 2 side. The fuel cell stack 1 is fastened with fastening bolts 7 and nuts 8 which are inserted into the bolt holes 6 from both ends.

As shown in FIGS. 1 to 3, the fuel cell module 2 includes a membrane-electrode assembly 10, a pair of separators (anode separator 11A and cathode separator 11C), an anode sealing member 9A, and a cathode sealing member 9C. And.

The membrane-electrode assembly 10 is provided on the polymer electrolyte membrane 15, the anode electrode 14A provided on the first main surface 15a of the polymer electrolyte membrane 15, and the second main surface 15b of the polymer electrolyte membrane 15. It has a cathode electrode 14C and the like. The anode electrode 14A has an anode catalyst layer 16 provided on the first main surface 15a of the polymer electrolyte film 15, and an anode gas diffusion layer 18A laminated on the anode catalyst layer 16. The cathode electrode 14C has a cathode catalyst layer 17 provided on the second main surface 15b of the polymer electrolyte film 15, and a cathode gas diffusion layer 18C laminated on the cathode catalyst layer 17.

The anode separator 11A is arranged on the anode gas diffusion layer 18A side of the membrane-electrode assembly 10. The cathode separator 11C is arranged on the cathode gas diffusion layer 18C side of the membrane-electrode assembly 10 and is paired with the anode separator 11A to sandwich the membrane-electrode assembly 10.

The anode sealing member 9A has an opening 26 and adheres the membrane-electrode assembly 10 and the anode separator 11A. The cathode sealing member 9C has an opening 26 and adheres the membrane-electrode assembly 10 and the cathode separator 11C. A cooling water separator 11W may be arranged outside the anode separator 11A and the cathode separator 11C.

In the present embodiment, the membrane-electrode assembly may be referred to as MEA. Further, the anode sealing member 9A and the cathode sealing member 9C may be collectively referred to as a sealing member 9. Further, the anode separator 11A, the cathode separator 11C, and the cooling water separator 11W may be collectively referred to as the separator 11. Further, the anode gas diffusion layer 18A and the cathode gas diffusion layer 18C may be collectively referred to as the gas diffusion layer 18.

Next, each component of the fuel cell stack 1 will be described in detail.

<Current collector plate>
The current collector plate 3 is arranged outside the laminate of the fuel cell module 2. The current collector plate 3 is formed by, for example, gold-plating a copper plate so that the electricity generated by the fuel cell module 2 can be efficiently collected. For the current collector plate 3, a metal material having good electrical conductivity, for example, iron, stainless steel, aluminum, or the like may be used. Further, surface treatment such as tin plating or nickel plating may be applied.

<End plate>
The end plate 4 is arranged outside the current collector plate 3. The end plate 4 is formed of, for example, an electrically insulating material, and also functions as an insulating plate. The end plate 4 is formed by injection molding using, for example, a polyphenylene sulfide resin. The pipe integrated with the end plate 4 is pressed against, for example, the manifold hole 12 of the laminated body of the fuel cell module 2 via a gasket (not shown). A spring 5 for applying a load to the fuel cell module 2 is arranged on the inner surface of the end plate 4, that is, the surface on the fuel cell module 2 side. The springs 5 are centrally arranged in a portion of the fuel cell module 2 that overlaps with the MEA 10 when stacked. The fuel cell stack 1 is fastened by the fastening bolts 7 and nuts 8 so that the urging force of the spring 5 becomes a predetermined value.

<Polymer electrolyte membrane>
For the polymer electrolyte membrane 15, a solid polymer material exhibiting proton conductivity, for example, a perfluorosulfonic acid membrane can be used. As the perfluorosulfonic acid membrane, for example, a Nafion membrane manufactured by DuPont can be adopted.

<Membrane-electrode assembly>
The MEA10 is an anode catalyst layer containing, for example, a carbon powder carrying a platinum ruthenium alloy catalyst as a main component on the anode side surface of the polymer electrolyte membrane 15 that selectively transports hydrogen ions, that is, the first main surface 15a. 16 is formed. Further, on the cathode side surface of the polymer electrolyte membrane 15, that is, the second main surface 15b, for example, a cathode catalyst layer 17 containing carbon powder supporting a platinum catalyst as a main component is formed. The anode gas diffusion layer 18A is laminated on the anode catalyst layer 16, and the cathode gas diffusion layer 18C is laminated on the cathode catalyst layer 17.

The outer peripheral shape of the MEA 10 is, for example, a quadrangular shape. The outer peripheral shape of the MEA is not limited to a quadrangular shape, and may be any shape such as a circular shape, an elliptical shape, or a polygonal shape other than a quadrangular shape.

<Gas diffusion layer>
The anode gas diffusion layer 18A is laminated on the anode catalyst layer 16 and has the functions of air permeability and electrical conductivity of fuel gas. Further, the cathode gas diffusion layer 18C is laminated on the cathode catalyst layer 17 and has the functions of air permeability and electrical conductivity of the oxidant gas. For the gas diffusion layer 18, for example, carbon paper or carbon cloth is used.

<Separator>
The anode separator 11A and the cathode separator 11C are formed in a flat plate shape. On the surfaces of the anode separator 11A and the cathode separator 11C that come into contact with the MEA 10, that is, the inner surfaces 11Ai and the inner surface 11Ci shown in FIG. The road groove 13C is formed. Cooling water flow path grooves 13W are formed on both sides of the outer surfaces 11Ao and 11Co and the cooling water separator 11W shown in FIG. 4 to be described later.

The separator 11 is made of a gas-impermeable conductive material. As the separator 11, for example, a resin-impregnated carbon material cut into a predetermined shape, a molded mixture of carbon powder and a resin material, a molded metal, or the like can be used.

<Sealing member>
FIG. 2 is a view of the MEA 10 and the sealing member 9 as viewed from a direction perpendicular to the first main surface 15a. Hereinafter, the direction perpendicular to the first main surface 15a may be referred to as a thickness direction. Further, a state viewed from a direction perpendicular to the first main surface 15a may be referred to as a plan view.

As shown in FIG. 2, in the opening 26 of the sealing member 9, a through hole 28 penetrating in the thickness direction, that is, in the Z-axis direction of FIG. 2 is formed in the central portion of the sealing member 9. That is, the sealing member 9 is formed in a shape (frame shape) in which the central portion of the member extending in the surface direction is cut off and the outer circumference is bordered. The through hole 28 of the present embodiment is formed in a quadrangular shape. The shape of the through hole 28 is not limited to a quadrangular shape, and may be any shape such as a circular shape, an elliptical shape, or a polygonal shape other than the quadrangular shape. The shape of the through hole 28 is, for example, the same as the outer peripheral shape of the sealing member 9. As a result, the frame-shaped sealing member 9 can be easily arranged on the outer peripheral portion 10a of the MEA 10.

The opening 26 is formed so as to penetrate in the thickness direction on the inner region A1 inside the outer peripheral portion 10a of the MEA 10 in the plane direction. Specifically, the opening 26 is formed so that the outer edge of the through hole 28 (the edge 26a of the opening 26) is located inside the outer peripheral portion 10a of the MEA 10 in the plane direction in a plan view.

The sealing member 9 adheres the outer peripheral portion 10a of the MEA10, the outer peripheral portion of the anode separator 11A on the MEA10 side surface, and the outer peripheral portion of the cathode separator 11C on the MEA10 side surface. The sealing member 9 (anode sealing member 9A and cathode sealing member 9C) of the present embodiment adheres the anode separator 11A and the cathode separator 11C with the polymer electrolyte membrane 15 on the outer peripheral portion 10a of the MEA 10 interposed therebetween. ing.

The anode sealing member 9A of the present embodiment is arranged so as to overlap the MEA 10 in the thickness direction in a region outside the end edge 26a in the surface direction. Similarly, the cathode sealing member 9C is also arranged so as to overlap in the thickness direction of the MEA 10 in a region outside the end edge 26a in the surface direction. The portion where the anode sealing member 9A, the cathode sealing member 9C, and the MEA 10 overlap is referred to as a region F1. In the present embodiment, the region F1 is a region from the edge 26a to a position separated by a predetermined length on the outside in the plane direction in a plan view.

The sealing member 9 is, for example, a thermosetting resin sheet. The sealing member 9 is not limited to this as long as the outer peripheral portion of the MEA 10 and the separator 11 can be adhered to each other. The sealing member 9 may be, for example, a fiber sheet enclosed in an insulating resin. The fiber sheet encapsulated in the resin may be, for example, a prepreg in which glass fibers are impregnated with an epoxy resin in consideration of insulation, heat resistance, gas permeability, and the like. Further, as the resin and the fiber, for example, an inorganic fiber such as a ceramic fiber may be used depending on the strength, the thickness, the coefficient of linear expansion, the contained substance and the like. Further, the resin may be another thermosetting resin such as a phenol resin, an unsaturated polyester resin, or a polyurethane resin, or a structure in which a resin containing fibers and another resin are laminated in multiple layers, or The composition may be partially different.

As shown in FIGS. 1 and 2, the outer peripheral portion of the separator 11 and the sealing member 9 are provided with manifold holes 12 and bolt holes 6 penetrating in the thickness direction, respectively. Although the bolt holes 6 are provided in the separator 11 in FIGS. 1 and 2, the fastening bolts 7 are arranged outside the separator 11 without providing the bolt holes 6 in the separator 11 to fasten the fuel cell module 2. You may. The manifold hole 12 is a through hole through which each of the fuel gas, the oxidant gas, and the cooling water flows. In a state where a plurality of fuel cell modules 2 are stacked, the manifold holes 12 of the respective fuel cell modules 2 are laminated and coupled to form a fuel gas manifold, an oxidant gas manifold, and a cooling water manifold.

Next, the configuration of the fuel cell module 2 will be described in detail with reference to FIG. FIG. 4 is a cross-sectional view of the fuel cell module 2 in a state before fastening.

As shown in FIG. 4, the fuel cell module 2 is configured to be sandwiched between the anode separator 11A and the cathode separator 11C in a state where the sealing member 9 is located on the outer peripheral portion 10a of the MEA 10. The fuel cell module 2 of the present embodiment has a pair of separators 11 in a state where the sealing member 9 is located on the first main surface 15a (FIG. 3) and the second main surface 15b of the polymer electrolyte membrane 15. It is composed by sandwiching it between. Further, in the fuel cell module 2, the positions of the outer peripheral portion of the separator 11 and the positions of the outer peripheral portion of the sealing member 9 are aligned in the thickness direction.

The distance t1 between the pair of separators 11 on the inner edge portion 20 of the sealing member 9 is larger than the distance t2 between the pair of separators 11 on the outer edge portion 22 of the sealing member 9. Specifically, the distance between the inner surface 11Ai on the MEA10 side of the anode separator 11A and the inner surface 11Ci on the MEA10 side of the cathode separator 11C is larger on the inner edge portion 20 than on the outer edge portion 22 of the sealing member 9. Further, in the present embodiment, the distance t1 between the pair of separators 11 is larger than the distance t3 between the pair of separators 11 on the outer peripheral portion 10a of the MEA 10.

Here, the outer edge portion 22 of the sealing member 9 means the outer peripheral portion of the frame-shaped sealing member 9 in a plan view. The inner edge portion 20 of the sealing member 9 means an inner peripheral portion of the frame-shaped sealing member 9 in a plan view, that is, an outer edge portion of the through hole 28.

The distance Da from the outer surface 11Ao of the anode separator 11A to the MEA10 (polymer electrolyte membrane 15) gradually increases from the outer peripheral portion to the central portion. Further, in the present embodiment, similarly to the anode side, the distance Dc from the outer surface 11Co of the cathode separator 11C to the MEA10 (polymer electrolyte membrane 15) gradually increases from the outer peripheral portion to the central portion. That is, both the outer surface 11Ao of the anode separator 11A and the outer surface 11Co of the cathode separator 11C swell in the thickness direction from the outer peripheral portion to the central portion.

Since the distance t1 between the separators 11 is larger than t2, the anode separator 11A and the cathode separator 11C can be shaped (drum-shaped) so that the region corresponding to the MEA 10 is convex. Specifically, the anode separator 11A and the cathode separator 11C can be shaped so that the portions of the MEA 10 located on the electrodes (anode electrode 14A, cathode electrode 14C) are convex. Therefore, the fuel cell module 2 can be formed into a shape that slightly swells from the outer peripheral portion toward the central portion.

Next, a configuration in which the fuel cell modules 2 are laminated and fastened will be described with reference to FIG. FIG. 5 is a partial cross-sectional view of the fuel cell stack 1 in a state where the fuel cell modules 2 are laminated and fastened.

As shown in FIG. 5, in the fuel cell stack 1, a plurality of fuel cell modules 2 are stacked in the thickness direction. In the fuel cell module 2 before fastening shown in FIG. 4, the outer surface of the separator 11 was formed in a convex shape, but in the fuel cell module 2 after fastening shown in FIG. 5, the central portion of the separator 11 is flat or omitted. It is in a flat state.

When the fuel cell module 2 is fastened, pressure is applied to the separator 11 in a state where the central portions of the convex separators 11 of the fuel cell module 2 are in contact with each other. At this time, the fastening makes it particularly easy to apply pressure to the region corresponding to the MEA 10 in the fuel cell module 2. That is, at the time of fastening, pressure is particularly likely to be applied to the bulging portion in the central portion of the fuel cell module 2. As a result, the central portion of the separator 11 is deformed toward the MEA10 side and becomes flat (substantially flat). The fuel cell module 2 shown in FIG. 5 includes a non-contact region in which the outer peripheral portion of the anode separator 11A and the outer peripheral portion of the adjacent cathode separator 11C are not in contact with each other.

Since the central portion of the separator 11 has a convex shape before fastening, a repulsive force acts on the central portion of the separator 11 which is in a flat state after fastening against the pressure of fastening. At the central portion of the separator 11 on which the repulsive force acts, the contact area between the separators 11 of the adjacent fuel cell modules 2 can be increased. Specifically, the contact area between the anode separator 11A of the fuel cell module 2 and the cathode separator 11C of the adjacent fuel cell module 2 can be increased. As a result, the electric resistance between the fuel cell modules 2 can be reduced, and the power generation performance of the fuel cell stack 1 can be improved.

Further, in order to increase the contact area between the separators 11 of the adjacent fuel cell modules 2 and reduce the electric resistance, the contact area between the separators 11 can be increased without using an additional member such as a displacement absorbing member. Can be done. Therefore, the number of parts of the fuel cell stack 1 can be reduced, the manufacturing process of the fuel cell stack 1 can be simplified, and the manufacturing cost can be reduced. That is, it is possible to manufacture the fuel cell stack 1 with improved power generation performance with a small number of parts and low cost.

Next, the relationship between the thickness and surface pressure of the separator and the contact area between the fuel cell modules 2 will be described with reference to FIG. FIG. 6 is a simulation result showing the relationship between the surface pressure applied to the MEA 10 (central surface pressure) and the contact area between adjacent separators 11.

In the simulation of FIG. 6, the thickness of the separator 11 is calculated in the range of 0.75 mm, 1.5 mm, and 3.0 mm, and the distance between the anode separator 11A and the cathode separator 11C is calculated in the range of 0.3 mm to 0.4 mm. did. Further, it is assumed that the central portion of the separator 11 bulges 0.01 mm in the thickness direction from the outer peripheral portion. FIG. 6 shows a simulation result when pressure is applied from the outside of the pair of separators 11 in such a configuration. In FIG. 6, the round marker shows the result when the thickness of the separator 11 is 0.75 mm, and the square marker shows the result when the thickness of the separator 11 is 1.5 mm, and the triangular marker shows the result. Shows the result when the thickness of the separator 11 is 3.0 mm.

Further, it is assumed that the thicknesses of the anode separator 11A and the cathode separator 11C are not uniform and are 0.01 mm thinner at the MEA10 portion. The simulation result shown in FIG. 6 is an example result and may be affected by the material physical characteristics and shape of each constituent member.

As shown in FIG. 6, regardless of whether the thickness of the separator 11 is 0.75 mm, 1.5 mm, or 3.0 mm, the larger the surface pressure applied to the MEA 10 at the time of fastening, the more the contact between the adjacent separators 11 is. The area has increased. When the surface pressure applied to the MEA 10 was the same, the thinner the separator 11, the larger the contact area between the adjacent separators 11.

From the results of FIG. 6, it was found that the thinner the thickness of the separator 11, the easier it is for the separator 11 to change its shape from a convex shape to a planar shape at the time of fastening, so that the contact area between adjacent separators 11 increases. In particular, by using a thin separator having a thickness of 1 mm or less, the contact area between adjacent separators 11 can be increased, and the influence on the pressure fluctuation of fastening can be reduced. Further, when the separator 11 in the portion in contact with the MEA 10 is thick, the contact area between the adjacent separators 11 becomes large as a whole, but even in this case, the contact area between the adjacent separators 11 at the time of fastening is increased. Can be increased.

Next, a method of manufacturing the fuel cell module 2 will be described with reference to FIG. 7. FIG. 7 is an exemplary flowchart of a method for manufacturing the fuel cell module 2. As shown in FIG. 7, the method for manufacturing the fuel cell module 2 includes a preparation step ST10, an arrangement step ST20, and a sealing step ST30.

In the preparation step ST10, the MEA 10, the pair of separators 11, and the sealing member 9 (anode sealing member 9A and cathode sealing member 9C) are prepared.

In the arrangement step ST30, the anode sealing member 9A and the cathode sealing member 9C are arranged so as to sandwich the MEA 10. Specifically, the sealing members 9A and 9C are arranged on the outer peripheral portion 10a of the MEA 10. That is, the anode sealing member 9A is arranged on the outer peripheral portion 10a on the first main surface 15a side of the MEA 10, and the cathode sealing member 9C is arranged on the outer peripheral portion 10a on the second main surface 15b side of the MEA 10. Further, a pair of separators 11 are arranged so as to sandwich the sealing member 9 and the MEA 10.

In the sealing step ST30, the MEA 10 and the anode separator 11A and the cathode separator 11C are bonded and sealed by the anode sealing member 9A and the cathode sealing member 9C. By sandwiching the MEA 10 and the sealing member 9 between the anode separator 11A and the cathode separator 11C and heating the MEA 10 and the sealing member 9, the pair of sealing members 9 can be integrated and the MEA 10 and the separator 11 can be adhered to each other.

In the sealing step ST30, a pressure larger than that of the inner edge portion 20 of the sealing member 9 is applied to the outer edge portion 22 of the sealing member 9 for sealing. As a result, the fuel cell module 2 is formed in which the distance t1 between the pair of separators 11 on the inner edge portion 20 of the sealing member 9 is larger than the distance t2 between the pair of separators 11 on the outer edge portion 22 of the sealing member 9. can do. That is, the central portion of the separator 11 can be formed by expanding in the thickness direction.

As described above, the fuel cell module 2 according to the present embodiment is manufactured through the preparation step ST10, the arrangement step ST20, and the sealing step ST30. The fuel cell stack 1 is completed by stacking and fastening the fuel cell modules 2 manufactured in this manner. As a result, it is possible to obtain the fuel cell stack 1 in which the electric resistance between the plurality of fuel cell modules 2 is reduced as well as in the individual fuel cell modules 2.

[effect]
The fuel cell module 2 according to the first embodiment includes a membrane-electrode assembly 10, a pair of separators 11 sandwiching the membrane-electrode assembly 10, a membrane-electrode assembly 10, and a pair of separators 11, respectively. A sealing member 9 for adhering and sealing the fuel cell 9 is provided. The membrane-electrode assembly 10 is provided on the polymer electrolyte membrane 15, the anode electrode 14A provided on the first main surface 15a of the polymer electrolyte membrane 15, and the second main surface 15b of the polymer electrolyte membrane 15. It has a cathode electrode 14C and the like. The sealing member 9 has an opening 26 penetrating in the thickness direction on the inner region A1 inside the outer peripheral portion 10a of the membrane-electrode assembly 10 in the plane direction. The sealing member 9 adheres the outer peripheral portion 10a of the membrane-electrode assembly 10 and the outer peripheral portions of the pair of separators 11 facing the membrane-electrode assembly 10. The distance t1 between the pair of separators 11 on the inner edge portion 20 of the sealing member 9 is larger than the distance t2 between the pair of separators 11 on the outer edge portion 22 of the sealing member 9.

According to this configuration, the contact area between the separator 11 and the member provided on the outside of the separator 11 can be increased. As a result, the electric resistance can be reduced and the power generation performance can be improved.

Further, at least one of the pair of separators 11 is formed so as to bulge in the thickness direction from the outer peripheral portion to the central portion.

According to this configuration, the contact area between the separator 11 and the member provided on the outside of the separator 11 can be further increased.

Further, the fuel cell stack 1 according to the first embodiment has at least two fuel cell modules 2, and at least two fuel cell modules 2 are laminated and fastened.

According to this configuration, the contact area between the separators 11 of the adjacent fuel cell modules 2 can be increased, and the electric resistance can be reduced.

Further, the method for manufacturing the fuel cell module 2 according to the first embodiment includes a preparation step ST10, an arrangement step ST20, and a sealing step ST30. In the preparation step ST10, the membrane-electrode assembly 10, the pair of separators 11, and the sealing member 9 are prepared. In the arrangement step ST20, the sealing member 9 is arranged so as to sandwich the outer peripheral portion 10a of the membrane-electrode assembly 10, and the pair of separators 11 are arranged so as to sandwich the membrane-electrode assembly 10 and the sealing member 9. In the sealing step ST30, a pressure larger than that of the inner edge portion 20 of the sealing member 9 is applied to the outer edge portion 22 of the sealing member 9 for sealing.

According to this manufacturing method, the distance t1 between the pair of separators 11 on the inner edge portion 20 of the sealing member 9 is made larger than the distance t2 between the pair of separators 11 on the outer edge portion 22 of the sealing member 9. Can be done.

The present disclosure is not limited to the above-described first embodiment, and can be carried out in various other modes. In the above-described embodiment, in the sealing step ST30, a pressure larger than that of the inner edge portion 20 of the sealing member 9 is applied to the outer edge portion 22 of the sealing member 9 for sealing, but the present invention is not limited to this. Another method as long as the distance t1 between the pair of separators 11 on the inner edge portion 20 of the sealing member 9 can be formed larger than the distance t2 between the pair of separators 11 on the outer edge portion 22 of the sealing member 9. May be.

For example, a step may be provided on the pressed surface so as to push the outer edge portion 22 of the sealing member 9 more strongly than the inner edge portion 20. Specifically, on the press surface of the press machine, the portion of the sealing member 9 that contacts the outer edge portion 22 may be formed so as to be located on the MEA side of the portion that contacts the inner edge portion 20.

Further, for example, a material may be selected such that the sealing member 9 is thinner than the MEA 10 (specifically, the anode electrode 14A and the cathode electrode 14C) when a constant pressure is applied. Further, by making the pressed surface an elastic body and pressing it, the distance between the separators 11 can be made different. That is, the central portion of the separator 11 can be formed by expanding in the thickness direction.

Moreover, although the fuel cell stack 1 having a plurality of fuel cell modules 2 has been described, the present invention is not limited to this. There may be one fuel cell module 2. At this time, for example, the fuel cell module 2 may be sandwiched between a pair of current collector plates 3 and a pair of end plates 4 and fastened to form a fuel cell. With such a configuration, the contact area between the separator 11 and the member (for example, the current collector plate 3) provided on the outside of the separator 11 can be increased.

Further, the sealing member 9 is said to have the anode separator 11A and the cathode separator 11C bonded to each other with the polymer electrolyte membrane 15 on the outer peripheral portion 10a of the MEA 10 interposed therebetween, but the present invention is not limited to this. The sealing member 9 may be arranged on the anode electrode 14A and the cathode electrode 14C to bond the MEA 10 and the separator 11.

(Embodiment 2)
The fuel cell module 30 according to the second embodiment of the present disclosure will be described. In the second embodiment, the points different from the first embodiment will be mainly described. In the second embodiment, the same or equivalent configurations as those in the first embodiment will be described with the same reference numerals. Further, in the second embodiment, the description overlapping with the first embodiment is omitted.

In the first embodiment, the configuration is described in which the ends of the separator 11 and the sealing member 9 are aligned on the entire circumference of the fuel cell module 2, but in the second embodiment, a part of the sealing member is the outer edge of the separator 11. A configuration located inside in the plane direction will be described.

FIG. 8 is a plan view of the sealing member 32 and the MEA 10 of the fuel cell module 30 according to the second embodiment. FIG. 9 is a sectional view taken along line BB of the sealing member 32 and MEA10 shown in FIG.

As shown in FIG. 8, in a plan view, at least a part of the outer edge of the sealing member 32 is located inside the outer edge of at least one of the separators 11A and 11C. In the present embodiment, in a plan view, at least a part of the outer edge of the sealing member 32 is located inside the outer edges of both the separators 11A and 11C. That is, the sealing member 32 shown in FIGS. 8 and 9 has a shape in which at least a part of the outer edge of the sealing member 9 of FIG. 2 is cut out in the thickness direction in the region A2.

By providing the notch region A2, when pressure is applied to the separator 11 in the thickness direction toward the notch region A2, the central portion of the separator 11 can be expanded more than the outer peripheral portion, so that the distance between the separators is t1. The inclination angle between and t2 can be increased.

Further, by providing the notch region A2, the sealing member 32 is housed in the notch region A2 even when the sealing member 32 shown in FIG. 9 is deformed in the plane direction by receiving pressure in the sealing process. be able to. Therefore, it is possible to prevent the sealing member 32 from protruding from the outer edges of the anode separator 11A and the cathode separator 11C.

Since the sealing member 32 does not protrude from the outer edge of the separator 11 to the outside in the surface direction, the fuel cell modules 30 can be easily aligned when the fuel cell modules 30 are laminated, and a highly accurate fuel cell stack can be formed. Can be done.

[effect]
In the fuel cell module 2 according to the second embodiment, when viewed from a direction perpendicular to the first main surface 15a, at least a part of the outer edge of the sealing member 32 is at least one of the pair of separators 11. Located inside the outer edge of.

According to this configuration, when pressure is applied to the separator 11 on the notch region A2, the central portion of the separator 11 can be expanded in the thickness direction with respect to the outer peripheral portion.

Further, when viewed from a direction perpendicular to the first main surface 15a, at least a part of the outer edge of the sealing member 32 is located inside the outer edges of both of the pair of separators 11.

According to this configuration, in both of the pair of separators 11, the central portion of the separator 11 can be more easily expanded in the thickness direction than the outer peripheral portion.

The shape of the sealing member 32 in this embodiment is an example, and is not limited to this. For example, the sealing member 34 as shown in FIG. 10 may be used. FIG. 10 is a plan view of the MEA 10 and the sealing member 34.

As shown in FIG. 10, the sealing member 34 has notched regions A3 at the four corners. The outer edge of the sealing member 34 may be located inside the outer edge of at least one of the separators 11A and 11C at a position symmetrically arranged from the center O1 in a plan view. Further, the outer edge of the sealing member 34 may be located inside the outer edges of both the separators 11A and 11C. The cutout region A3 may be formed symmetrically from the center in the plan view of the sealing member 9. That is, the sealing member 34 may be formed point-symmetrically with respect to the center O1 in a plan view. In this case, when pressure is applied to the fuel cell module in the sealing step ST30, the pressure is likely to be applied symmetrically with respect to the center O1, and a highly accurate fuel cell module can be obtained.

By appropriately combining any of the above-mentioned various embodiments, the effects of each can be achieved.

Although the present disclosure has been fully described in connection with preferred embodiments with reference to the accompanying drawings, various modifications and modifications are obvious to those skilled in the art. It should be understood that such modifications and amendments are included therein, as long as they do not deviate from the scope of the present disclosure by the appended claims. In addition, changes in the combination and order of elements in the embodiments can be realized without departing from the scope and ideas of the present disclosure.

According to the fuel cell module and the fuel cell stack according to the present disclosure, and the method for manufacturing the fuel cell module, it is possible to provide a fuel cell module capable of realizing a fuel cell stack having excellent power generation performance. Therefore, it is useful in the field of fuel cells used for portable power supplies, power supplies for electric vehicles, home cogeneration systems, and the like.

1 Fuel cell stack 2,30 Fuel cell module 3 Current collector plate 4 End plate 5 Spring 6 Bolt hole 7 Fastening bolt 8 Nut 9,32 Sealing member 9A Anode sealing member 9C Cathode sealing member 10 Film-electrode junction 10a Outer circumference 11 Separator 11A Anode separator 11C Cathode separator 11W Cooling water separator 11Ai, 11Ci Inner surface 11Ao, 11Co Outer surface 12 Manifold hole 13A Fuel gas flow path groove 13C Oxidizer gas flow path groove 13W Cooling water flow path groove 14A Anode electrode 14C Cathode electrode 15 Polymer electrolyte membrane 15a 1st main surface 15b 2nd main surface 16 Anode catalyst layer 17 Anode catalyst layer 18 Gas diffusion layer 18A Anode gas diffusion layer 18C Cathode gas diffusion layer 20 Inner edge 22 Outer edge 26 Opening 26a Edge edge 28 Through hole 90 Sealing member 100 Film-electrode junction 111 Anode separator 112 Cathode separator 131, 132 Gas flow path groove 150 Electrolyte membrane 151 First main surface 152 Second main surface 160 Anode catalyst layer 170 Anode catalyst layer 181 Anode gas diffusion layer 182 Anode gas diffusion layer 190 Anode electrode 200 Cathode electrode 210 Fuel cell module A1 Inner area A2, A3 Notch area

Claims (8)

Membrane-electrode assembly having a polymer electrolyte membrane, an anode electrode provided on the first main surface of the polymer electrolyte membrane, and a cathode electrode provided on the second main surface of the polymer electrolyte membrane. With the body
A pair of separators sandwiching the membrane-electrode assembly,
A sealing member that adheres and seals the membrane-electrode assembly and each of the pair of separators.
With
The sealing member has an opening penetrating in the thickness direction on the inner region inside in the plane direction from the outer peripheral portion of the membrane-electrode assembly, and the outer peripheral portion of the membrane-electrode assembly and the film-. The outer peripheral portions of the pair of separators facing the electrode assembly are bonded to each other.
A fuel cell module in which the distance between the pair of separators on the inner edge of the sealing member is greater than the distance between the pair of separators on the outer edge of the sealing member. The fuel cell module according to claim 1, wherein at least one of the pair of separators is formed to bulge in the thickness direction from the outer peripheral portion to the central portion. 1 or claim 1, wherein at least a part of the outer edge of the sealing member is located inside the outer edge of at least one of the pair of separators when viewed from a direction perpendicular to the first main surface. 2. The fuel cell module according to 2. The fuel according to claim 3, wherein at least a part of the outer edge of the sealing member is located inside both outer edges of the pair of separators when viewed from a direction perpendicular to the first main surface. Battery module. The outer edge of the sealing member is at least one outer edge of the pair of separators at a position symmetrically arranged from the center of the sealing member when viewed from a direction perpendicular to the first main surface. The fuel cell module according to claim 3 or 4, which is located inside the fuel cell module. The outer edge of the sealing member is inside the outer edges of both of the pair of separators at positions symmetrically arranged from the center of the sealing member when viewed from a direction perpendicular to the first main surface. The fuel cell module according to claim 5, which is located in. It has at least two fuel cell modules according to any one of claims 1 to 6.
A fuel cell stack in which at least two of the fuel cell modules are stacked and fastened. A membrane-electrode assembly having a polymer electrolyte membrane, an anode electrode provided on the first main surface of the polymer electrolyte membrane, and a cathode electrode provided on the second main surface of the polymer electrolyte membrane. A preparatory step for preparing a pair of separators and a sealing member,
An arrangement step of arranging the sealing member so as to sandwich the outer peripheral portion of the membrane-electrode assembly, and arranging the pair of separators so as to sandwich the membrane-electrode assembly and the sealing member.
A sealing step of sealing with a pressure larger than the inner edge of the sealing member applied to the outer edge of the sealing member.
How to manufacture a fuel cell module, including.

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