JP2020198201A - Fuel cell stack - Google Patents

Abstract

To provide a fuel cell stack in which sealability is improved between a bead part and a frame.SOLUTION: A first separator 20 includes a first proximal region 21, and a first bead part 24, the first bead part includes a first crown 25 located at a position closer to a first frame 50 than the first proximal region, a first side part 26 continuous between one end of the first crown and the first proximal region in the first direction, and a second side part 27 continuous between the other end of the first crown and the first proximal region in the first direction. A first elastic part 60 is provided between the first crown and the first frame, and includes first and second end regions 61, 62 abutting on the one and the other end of the first crown, respectively, and a first central region 63 located between the first and second end regions. Degree of elasticity of the first central region is larger than those of the first and second end regions, in a fuel cell stack 1.SELECTED DRAWING: Figure 6

Description

The present invention relates to a fuel cell stack.

The fuel cell stack is composed of a plurality of single cells stacked together. In each single cell, an elastic body is arranged between the bead portion formed on the separator and the frame supporting the membrane electrode gas diffusion layer joint body, and the sealing property between the bead portion and the frame is ensured ( For example, see Patent Document 1).

JP-A-2018-129164

However, in a state where a plurality of single cells are fastened, a compressive load acts in the stacking direction, and the central portion of the top of the bead portion in contact with the elastic body may be curved so as to be separated from the frame. When deformed in this way, a portion where the surface pressure of the top portion of the bead portion is low in the width direction is generated, and the sealing property between the bead portion and the frame may be deteriorated.

Therefore, an object of the present invention is to provide a fuel cell stack having an improved sealing property between the bead portion and the frame.

For the above purpose, in a fuel cell stack in which a plurality of single cells are laminated, at least one of the plurality of single cells supports a first film electrode gas diffusion layer junction and the first membrane electrode gas diffusion layer junction. The first frame includes the first film electrode gas diffusion layer junction and the first separator facing the first frame, and the first separator is the first base portion and the first frame from the first base portion. The first bead portion includes a first bead portion that protrudes toward the surface and has a width along the first direction, and the first bead portion is a first top portion that is closer to the first frame than the first base portion. Between one end of the first apex in the first direction and a continuous first side portion between the first base, and between the other end of the first apex and the first base in the first direction. A first elastic portion is provided between the first top portion and the first frame, including a continuous second side portion, and the first elastic portion is one end of the first top portion and the said. The elastic coefficient of the first central region includes a first and second end region that abuts on the other end of the first top, respectively, and a first central region that is located between the first and second end regions. Can be achieved with a fuel cell stack that is greater than each of the first and second end regions.

Further, the above object is in a fuel cell stack in which a plurality of single cells are laminated, and at least one of the plurality of single cells is a first film electrode gas diffusion layer junction and the first membrane electrode gas diffusion layer junction. The first frame includes the first film electrode gas diffusion layer junction and the first separator facing the first frame, and the first separator is the first base portion and the first to the first base portion. The first bead portion includes a first bead portion that protrudes toward one frame and has a width along the first direction, and the first bead portion is a first top portion located closer to the first frame than the first base portion. , The first side portion continuous between one end of the first top portion in the first direction and the first base portion, and the other end of the first top portion in the first direction and the first base portion. A first elastic portion is provided between the first top portion and the first frame, including a second side portion continuous between the first elastic portions, and the first elastic portion is one end of the first top portion. The elasticity of the first central region, including the first and second end regions abutting the other end of the first top and the first central region located between the first and second end regions, respectively. The rate can be achieved by a fuel cell stack that is less than each elastic rate in the first and second end regions.

The width of the first central region may be narrower than the total width of the first and second end regions.

The width of the first central region may be wider than the total width of the first and second end regions.

The first elastic portion may be integrally formed with the first frame in advance.

The first elastic portion may include a first separation region that is continuously formed in the first end region and is separated from the first top portion.

The width of the first separation region may be wider than the total width of the first and second end regions and the first central region.

The first separation region may be formed of the same material as the first end region.

The first separation region may be formed of the same material as the first central region.

The first elastic portion may include a second separated region that is continuously formed in the second end region and separated from the first top portion.

The width of the second separation region may be wider than the total width of the first and second end regions and the first central region.

The second separation region may be formed of the same material as the second end region.

The second separation region may be formed of the same material as the first central region.

The at least one of the plurality of single cells includes the first film electrode gas diffusion layer junction and the second separator facing the first separator on the side opposite to the first frame, and the plurality of single cells. The other single cell adjacent to the at least one includes the second membrane electrode gas diffusion layer junction and the second frame supporting the second membrane electrode gas diffusion layer junction, and the second membrane electrode gas. The diffusion layer joint and the second frame face the second separator, and the second separator projects from the second base portion abutting the first base portion and the second base portion toward the second frame. The second bead portion includes a second bead portion having a width along the first direction, and the second bead portion is a second top portion located closer to the second frame than the second base portion, in the first direction. A third side portion continuous between one end of the second apex and the second base portion, and a fourth continuous portion between the other end of the second apex portion in the first direction and the second base portion. A second elastic portion is provided between the second top portion and the second frame, including a side portion, and the second elastic portion is formed on one end of the second top portion and the second top portion. The elastic coefficient of the second central region includes the third and fourth end regions that come into contact with the other ends and the second central region located between the third and fourth end regions, respectively. And may be larger than each elastic coefficient of the fourth end region.

The at least one of the plurality of single cells includes the first film electrode gas diffusion layer junction and the second separator facing the first separator on the side opposite to the first frame, and the plurality of single cells. The other single cell adjacent to the at least one includes the second membrane electrode gas diffusion layer junction and the second frame supporting the second membrane electrode gas diffusion layer junction, and the second membrane electrode gas. The diffusion layer joint and the second frame face the second separator, and the second separator projects from the second base portion abutting the first base portion and the second base portion toward the second frame. The second bead portion includes a second bead portion having a width along the first direction, and the second bead portion is a second top portion located closer to the second frame than the second base portion, in the first direction. A third side portion continuous between one end of the second apex and the second base portion, and a fourth continuous portion between the other end of the second apex portion in the first direction and the second base portion. A second elastic portion is provided between the second top portion and the second frame, including a side portion, and the second elastic portion is formed on one end of the second top portion and the second top portion. The elastic coefficient of the second central region includes the third and fourth end regions that come into contact with the other ends and the second central region located between the third and fourth end regions, respectively. And may be smaller than each elastic coefficient of the fourth end region.

The width of the second central region may be narrower than the total width of the third and fourth end regions.

The width of the second central region may be wider than the total width of the third and fourth end regions.

The second elastic portion may be integrally formed with the second frame in advance.

The second elastic portion may include a third separated region that is continuously formed in the third end region and separated from the second top portion.

The second elastic portion may include a fourth separated region that is continuously formed in the fourth end region and separated from the second top portion.

It is possible to provide a fuel cell stack with improved sealing performance between the bead portion and the frame.

FIG. 1 is an exploded perspective view of a single cell of a fuel cell stack. FIG. 2 is a front view of the separator. FIG. 3 is a cross-sectional view of a single cell corresponding to the line AA shown in FIG. FIG. 4A is an explanatory diagram of a comparative example, and FIG. 4B is a graph showing a surface pressure distribution in the + X direction acting on each top of the separator of the comparative example. FIG. 5A is an explanatory diagram of the present embodiment, and FIG. 5B is a graph showing the surface pressure distribution in the + X direction acting on the tops of the separators of the present embodiment. FIG. 6A is a partial cross-sectional view showing the periphery of the bead portion of the single cell before fastening, FIG. 6B is a partial cross-sectional view showing the periphery of the bead portion of the single cell after fastening, and FIG. 6C is a partial cross-sectional view after fastening. It is a graph which showed the surface pressure distribution of the top of the bead part of. FIG. 7A is a partial cross-sectional view showing the periphery of the bead portion of the single cell before fastening in the first modified example, and FIG. 7B shows the periphery of the bead portion of the single cell after fastening in the first modified example. FIG. 7C is a partial cross-sectional view shown, and FIG. 7C is a graph showing the surface pressure distribution of the top of the single cell after fastening in the first modification. FIG. 8A is a partial cross-sectional view showing the periphery of the bead portion of the single cell before fastening in the second modified example, and FIG. 8B shows the periphery of the bead portion of the single cell after fastening in the second modified example. FIG. 8C is a partial cross-sectional view shown, and FIG. 8C is a graph showing the surface pressure distribution of the top of the single cell after fastening in the second modification. FIG. 9A is a partial cross-sectional view showing the periphery of the bead portion of the single cell before fastening in the third modified example, and FIG. 9B shows the periphery of the bead portion of the single cell after fastening in the third modified example. FIG. 9C is a partial cross-sectional view shown, and FIG. 9C is a graph showing the surface pressure distribution of the top of the single cell after fastening in the third modification. FIG. 10A is a partial cross-sectional view showing the periphery of the bead portion of the single cell before fastening in the fourth modified example, and FIG. 10B shows the periphery of the bead portion of the single cell after fastening in the fourth modified example. FIG. 10C is a partial cross-sectional view shown, and FIG. 10C is a graph showing the surface pressure distribution of the top of a single cell after fastening in the fourth modification.

[Outline configuration of fuel cell stack]
FIG. 1 is an exploded perspective view of a single cell 2 of the fuel cell stack 1. The fuel cell stack 1 is formed by stacking a plurality of single cells 2. In FIG. 1, only one single cell 2 is shown, and the other single cells are omitted. Note that FIG. 1 shows the X direction, the Y direction, and the Z direction that are orthogonal to each other. The X direction and the Y direction correspond to the lateral direction and the longitudinal direction of the single cell 2 formed in a substantially rectangular shape. The Z direction corresponds to the direction in which a plurality of single cells 2 are laminated.

The fuel cell stack 1 is a polymer electrolyte fuel cell that generates electricity by being supplied with an anode gas (for example, hydrogen) and a cathode gas (for example, oxygen) as reaction gases. The single cell 2 includes a membrane electrode gas diffusion layer assembly 10 (hereinafter referred to as MEGA (Membrane Electrode Gas diffusion layer assembly)), a frame-shaped frame 50, and an anode separator 20 and a cathode separator 40 (hereinafter referred to as a separator). including. The separator 20 is arranged on the + Z direction side of the MEGA 10 and the frame 50 and faces them. The separator 40 is arranged on the + Z direction side of the separator 20 and faces the separator 40. The frame 50 has an insulating property, and is a frame-shaped member whose inner peripheral portion is joined to the outer peripheral portion of the MEGA 10. MEGA10 is an example of a first film electrode gas diffusion layer bonded body. The frame 50 is an example of the first frame. The separator 20 is an example of the first separator. The separator 40 is an example of a second separator.

MEGA10 has an anode gas diffusion layer 16a and a cathode gas diffusion layer 16c (hereinafter, referred to as a diffusion layer). In addition, MEGA 10 includes a membrane electrode assembly (hereinafter referred to as MEA (Membrane Electrode Assembly)) sandwiched between diffusion layers 16a and 16c. The MEA includes an electrolyte membrane and an anode catalyst layer and a cathode catalyst layer. The anode catalyst layer is formed on the surface of the electrolyte membrane on the separator 20 side, and the diffusion layer 16a is bonded to the anode catalyst layer. The cathode catalyst layer is formed on the surface of the electrolyte membrane opposite to the separator 20, and the diffusion layer 16c is bonded to the cathode catalyst layer. The electrolyte membrane is a solid polymer thin film that exhibits good proton conductivity in a wet state, and is, for example, a fluorine-based ion exchange membrane. The catalyst layer is formed by applying a catalyst ink containing, for example, a carbon carrier carrying platinum (Pt) or the like and ionomer having proton conductivity to an electrolyte membrane. The diffusion layers 16a and 16c are formed of a material having gas permeability and conductivity, for example, a porous fiber base material such as carbon fiber or graphite fiber.

The separators 20 and 40 and the frame 50 are formed so that the holes a1 to a6 penetrate. Holes a1 to a3 are formed on one side of the two short sides of the separators 20 and 40, and the frame 50, and holes a4 to a6 are formed on the other side. The hole a1 defines the cathode inlet manifold. The hole a2 defines the cooling water inlet manifold. Hole a3 defines the anode outlet manifold. Hole a4 defines the anode inlet manifold. The hole a5 defines the cooling water outlet manifold. Hole a6 defines the cathode outlet manifold.

On the surface of the separator 20 facing the MEGA 10, an anode flow path portion 20A (hereinafter, referred to as a flow path portion) is formed in which the anode gas flows through the anode inlet manifold and the anode outlet manifold. On the surface opposite to the surface of the separator 20 facing the MEGA 10, a cooling water flow path portion 20B (hereinafter referred to as a flow path portion) through which the cooling water inlet manifold and the cooling water outlet manifold are communicated and the cooling water flows flows. It is formed. On the surface of the separator 40 facing the separator 20, the cooling water flow path portion 40B (hereinafter referred to as a flow path portion) through which the cooling water flows through the cooling water inlet manifold and the cooling water outlet manifold together with the flow path portion 20B. Is formed. On the surface opposite to the surface of the separator 40 facing the separator 20, a cathode flow path portion 40A (hereinafter, referred to as a flow path portion) is formed in which the cathode gas flows through the cathode inlet manifold and the cathode outlet manifold. Has been done. The flow path portions 20A and 20B are composed of a plurality of groove portions extending in the Y direction, which is the longitudinal direction of the separator 20, and arranged side by side in the X direction. The same applies to the flow path portions 40A and 40B.

The flow path portions 20B and 40B are integrally formed on the front and back sides of the flow path portions 20A and 40A, respectively. The separators 20 and 40 are thin plate-shaped members formed of a material having gas-blocking property and conductivity, and formed of press-formed stainless steel or a metal such as titanium or a titanium alloy.

The separator 20 is formed with a bead portion 24 that circulates along the outer peripheral edge, which will be described in detail later. Similarly, the separator 40 is also formed with a bead portion 44. The bead portion 24 surrounds the flow path portions 20A and 20B and the holes a1 to a6, and the bead portion 44 surrounds the flow path portions 40A and 40B and the holes a1 to a6. The bead portions 24 and 44 face each other in the Z direction in a state where the separators 20 and 40 are laminated. Further, the separator 20 is formed with bead portions 291 to 296 surrounding each of the holes a1 to a6, and similarly, the separator 40 is provided with bead portions 491 to 496 surrounding each of the holes a1 to a6. It is formed. The bead portions 291 to 296 also face each other in the Z direction with the bead portions 491 to 496, respectively. These bead portions 24, 44, 291-296, and 491-496 prevent leakage of anode gas, cathode gas, and cooling water.

FIG. 2 is a front view of the separator 40. FIG. 2 shows a case where the separator 40 is viewed from the + Z direction side. In FIG. 2, the welding lines L1, L3, L4, L6, and L10 between the separator 40 and the separator 20 are shown by dotted lines. Welding lines L1, L3, L4, and L6 surround the bead portions 491, 493, 494, and 496, respectively. The welding line L10 surrounds the bead portion 44. The separators 20 and 40 are welded along these welding lines before the plurality of single cells 2 are laminated. The method of joining the separators 20 and 40 is not limited to welding, and an adhesive may be used.

[State before fastening]
FIG. 3 is a cross-sectional view of the single cell 2 corresponding to the line AA shown in FIG. FIG. 3 shows another single cell 2-1 adjacent to the single cell 2 on the + Z direction side, and another single cell frame 50-2 adjacent to the single cell 2-1 in the + Z direction. The single cell 2-1 is the same member as the single cell 2, but has different reference numerals for convenience of explanation. Therefore, the separators 20 and 20-1 are the same members, the separators 40 and 40-1 are also the same members, and the frames 50, 50-1 and 50-2 are also the same members. Further, the elastic portions 60, 60-1, 70-1, and 70-2, which will be described in detail later, are the same member. The separators 20-1 and 40-1, the frame 50-1, and the elastic portions 60-1 and 70-1 are included in the single cell 2-1. The elastic portion 70-2 and the frame 50-2 are included in another single cell adjacent to the single cell 2-1 on the + Z direction side.

As described above, the separators 20 and 40 are welded, and the separators 20-1 and 40-1 are similarly welded. FIG. 3 shows a state in which the separators 20 and 40 and the separators 20-1 and 40-1 are displaced in the X direction before the plurality of stacked single cells 2, 2-1 and the like are fastened. Is shown. In the state before fastening, the compressive load does not act on the stacked single cells 2, 2-1 and the like in the Z direction, which is the stacking direction. In the fastening work, terminal plates, insulators, and end plates are laminated in order from the laminate side on one end side and the other end side of the laminate composed of a plurality of single cells 2, 2-1 and the like, and the terminal plates, insulators, and end plates are laminated on both ends. This is done by connecting the arranged end plates with a plurality of tension plates.

[Structure of bead portions 24 and 44]
The structure of the bead portion 24 will be described. The bead portion 24 of the separator 20 projects from the base portion 21 in the −Z direction, that is, toward the frame 50. In FIG. 3, the bead portion 24 has a width in the X direction and extends in the Y direction. The base 21 has a flat plate shape extending substantially parallel to the XY plane. The bead portion 24 includes a top portion 25 and side portions 26 and 27. The top 25 is closer to the frame 50 than the base 21 and is substantially parallel to the XY plane. The side portion 26 is continuous between the base portion 21 and one end of the top portion 25 in the + X direction and is inclined with respect to the base portion 21. Specifically, the side portion 26 is tilted at an angle greater than 90 degrees with the base portion 21 on the frame 50 side. The side portion 27 is continuous between the base portion 21 and the other end of the top portion 25 in the + X direction and is inclined with respect to the base portion 21. The side portion 27 is also inclined at an angle larger than 90 degrees with respect to the base portion 21 on the frame 50 side. The side portions 26 and 27 face each other in the X direction.

The bead portion 24 is an example of the first bead portion. The base 21 is an example of the first base. The top 25 is an example of the first top. The side portions 26 and 27 are examples of the first and second side portions, respectively. A plurality of groove portions and other bead portions that integrally form the flow path portions 20A and 20B on the front and back sides are also provided so as to project from the base portion 21 in the −Z direction, similarly to the bead portion 24.

Next, the bead portion 44 will be described. The bead portion 44 of the separator 40 projects from the base portion 41 in the + Z direction, that is, toward the frame 50-1. Similar to the bead portion 24 of the separator 20, the bead portion 44 also has a width in the X direction and extends in the Y direction in FIG. The base portion 41 has a flat plate shape extending substantially parallel to the base portion 21, and is welded to the base portion 21 according to the above-mentioned welding line. The bead portion 44 includes a top portion 45 and side portions 46 and 47. The top 45 is closer to the frame 50-1 than the base 41. The side portion 46 is continuous between the base portion 41 and one end of the top portion 45 in the + X direction and is inclined with respect to the base portion 41. The side portion 47 is continuous between the base portion 41 and the other end of the top portion 45 in the + X direction and is inclined with respect to the base portion 41. The side portions 46 and 47 face the side portions 26 and 27 of the bead portion 24 of the separator 20 in the Y direction, respectively.

Since FIG. 3 shows the state before fastening, the tops 25 and 45 are in a state substantially parallel to the XY plane. The bead portion 44 is an example of the second bead portion. The base 41 is an example of a second base. The top 45 is an example of a second top. The side portions 46 and 47 are examples of the third and fourth side portions, respectively. A plurality of groove portions and other bead portions that integrally form the flow path portions 40A and 40B on the front and back sides are also provided so as to project from the base portion 41 in the + Z direction, similarly to the bead portion 44.

[Rough configuration of elastic parts 60 and 70-1]
An elastic portion 60 is arranged between the top 25 of the bead portion 24 of the single cell 2 and the frame 50. The elastic portion 60 has substantially the same width as the top portion 25 and extends in the Y direction like the top portion 25. The elastic portion 60 is previously adhered to the top 25 of the separator 20, but is not limited thereto. Similarly, an elastic portion 70-1 is arranged between the top 45 of the bead portion 44 of the separator 40 of the single cell 2 and the frame 50-1 of the single cell 2-1. The elastic portion 70-1 has substantially the same width as the top portion 45 and extends in the Y direction like the top portion 45. Like the elastic portion 60, the elastic portion 70-1 is previously adhered to the top 45 of the separator 40, but the present invention is not limited to this. The same applies to the elastic portions 60-1 and 70-2. These elastic parts may be foamed rubber, non-foamed rubber, thermoplastic elastomer, or a mixture of rubber and thermoplastic elastomer. Further, the elastic portion 60 includes end regions 61 and 62 and a central region 63 having different elastic moduli, which will be described in detail later. The same applies to the other elastic portions 60-1, 70-1, and 70-2.

The frame 50 is made of a material having a higher elastic modulus than these elastic portions, and is made of a synthetic resin such as polyethylene terephthalate, polyethylene naphthalate, or polybutylene naphthalate. The elastic portion 60 is an example of the first elastic portion. The elastic portion 70-1 is an example of the second elastic portion. Single cell 2-1 is an example of another single cell adjacent to single cell 2. The frame 50-1 is an example of the second frame and supports MEGA (not shown). MEGA supported by the frame 50-1 is an example of a second film electrode gas diffusion layer bonded body.

It is desirable that a plurality of single cells are fastened without the misalignment as shown in FIG. 3, but the misalignment may occur depending on the positioning accuracy of each single cell during the fastening work, dimensional error, and the like. It is possible that it will occur. When a plurality of single cells or the like are fastened in a state where the misalignment occurs in this way, problems such as the comparative example described below may occur.

[State after conclusion of comparative example]
FIG. 4A is an explanatory diagram of a comparative example. FIG. 4A shows a state in which the separators 20 and 40 and the separators 20-1 and 40-1 are displaced in the X direction, and the single cells 2x, 2x-1, etc. are fastened. In the single cells 2x and 2x-1 of the fuel cell stack 1x of the comparative example, the elastic portions 60x, 60x-1, 70x-1 and 70x-2 are used. Unlike the present embodiment described above, these elastic portions are formed of a single material having the same elastic modulus.

When the single cells 2x and 2x-1 are fastened and a compressive load is applied in the Z direction, the bead portion 24 of the separator 20 is deformed so as to be crushed. Specifically, the side portions 26 and 27 are deformed so as to fall, and the central portion of the top portion 25 is curved so as to be separated from the frame 50. As a result, the elastic portion 60x is also deformed following the top portion 25, and a gap is created between the central portion of the elastic portion 60x and the frame 50. The bead portion 44 of the separator 40 is similarly deformed, and a gap is formed between the central portion of the elastic portion 70x-1 and the frame 50-1. The same applies to the elastic portions 60x-1 and 70x-2.

FIG. 4B is a graph showing the surface pressure distribution in the + X direction acting on each top 25 of the separators 20 and 20-1 of the comparative example. The surface pressure of the top 25 of the separator 20 is relatively high at both ends of the top 25 and relatively low at the center. This is because the elastic portion 60x is deformed like the top portion 25, and the central portion of the elastic portion 60x is separated from the frame 50. The same applies to the surface pressure of the top 25 of the separator 20-1. The surface pressure distribution of the top 45 of the separator 40 is substantially the same as the surface pressure distribution of the top 25 of the separator 20, and the surface pressure distribution of the top 45 of the separator 40-1 is the surface of the top 25 of the separator 20-1. It is almost the same as the pressure distribution.

As described above, the positions of the separators 20 and 40 and the separators 20-1 and 40-1 are displaced in the X direction. Therefore, as shown in FIG. 4B, the positions of both ends of the top 25 of the separator 20 having high surface pressure. And the positions of both ends where the surface pressure of the top 25 of the separator 20-1 is high may not overlap in the Z direction. Therefore, between the top 25 of the separator 20 and the frame 50, between the top 45 of the separator 40 and the frame 50-1, between the top 25 of the separator 20-1 and the frame 50-1, the separator 40-1 The sealability between the top 45 of the frame and the frame 50-2 may be reduced.

[State after conclusion of this embodiment]
FIG. 5A is an explanatory diagram of this embodiment. FIG. 5A shows a state after fastening the single cells 2, 2-1 and the like in a state where the separators 20 and 40 and the separators 20-1 and 40-1 are displaced in the X direction. In this example as well, the top portions 25 and 45 are elastically deformed as in the comparative example, but the method of deformation of the elastic portions 60 and 70-1 is different from that of the above-mentioned comparative example. For example, the elastic portion 60 is deformed so as to increase the thickness of the central portion, and is in close contact with the frame 50 without being separated from the frame 50. The same applies to the elastic portions 60-1, 70-1, and 70-2.

FIG. 5B is a graph showing the surface pressure distribution in the + X direction acting on the top 25 of each of the separators 20 and 20-1 of this embodiment. The elastic portion 60 is deformed so as to be in close contact with both the top portion 25 and the frame 50, and the surface pressure of the top portion 25 becomes substantially equal. The same applies to the surface pressure acting on the top 25 of the separator 20-1. Therefore, even if the separator is misaligned, the position of the portion where the surface pressure of the top 25 of the separator 20 is high and the position of the portion where the surface pressure of the top 25 of the separator 20-1 is high are in the Z direction. The amount of overlap can be secured. Therefore, the sealing property between the bead portions facing each other and the frame is improved.

It is desirable that the surface pressure at the top of the bead portion is uniform even when the above-mentioned misalignment does not occur. For example, if the surface pressure of the top 25 of the separator 20 is non-uniform as shown in FIG. 4A, there is a possibility that a portion having insufficient adhesion between the elastic portion 60x and the frame 50 may occur, and the sealing property may deteriorate. Because there is.

[Details of elastic parts 60 and 70-1]
The elastic portions 60 and 70-1 will be described in detail. FIG. 6A is a partial cross-sectional view showing the periphery of the bead portions 24 and 44 of the single cell 2 before fastening. FIG. 6B is a partial cross-sectional view showing the periphery of the bead portions 24 and 44 of the single cell 2 after fastening. FIG. 6C is a graph showing the surface pressure distribution of the top 25 of the bead portion 24 after fastening.

The elastic portion 60 includes end regions 61 and 62 and a central region 63. The end regions 61 and 62 are located at one end and the other end in the + X direction, which is the width direction of the bead portion 24. The central region 63 is located between the end regions 61 and 62. The elastic modulus of the central region 63 is larger than the elastic modulus of each of the end regions 61 and 62. The elastic modulus is a physical property value indicating the difficulty of deformation. Therefore, the central region 63 is less likely to be elastically deformed than the end regions 61 and 62. The end regions 61 and 62 are made of the same material, and the central region 63 is made of a different material than the end regions 61 and 62. For example, the material of the end regions 61 and 62 is a styrene-based or olefin-based thermoplastic elastomer, and the material of the central region 63 is a urethane-based, ester-based, or amide-based thermoplastic elastomer.

The thicknesses of the end regions 61 and 62 and the central region 63 in the Z direction are substantially the same in the state before fastening. The widths W1, W2, and W3 of the end region 61, the end region 62, and the center region 63 are also substantially the same size in the state before fastening. Further, in the state before fastening, the width W3 of the central region 63 is narrower than the sum of the width W1 of the end region 61 and the width W2 of the end region 62. Similarly, the elastic portion 70-1 includes end regions 71 and 72 and a central region 73, and has the same material, size, and shape as the end regions 61 and 62 and the central region 63, respectively. The end regions 61 and 62 are examples of the first and second end regions, respectively. The central region 63 is an example of the first central region. The end regions 71 and 72 are examples of the third and fourth end regions, respectively. The central region 73 is an example of the second central region.

As shown in FIG. 6B, in the state after fastening, a large compressive load acts on the end regions 61 and 62 from one end and the other end of the top 25 of the bead portion 24 in the + X direction, and the top 25 is the central region. Curve away from 63. When a large compressive load acts on the end regions 61 and 62, the end regions 61 and 62 tend to elastically deform so as to extend in the X direction. Here, the portion of the end region 61 near the central region 63 is restricted from extending in the + X direction by the central region 63, which is less elastically deformed than the end region 61, and the portion of the end region 62 near the central region 63 is the end. The central region 63, which is less elastically deformed than the region 62, regulates the extension in the −X direction. As a result, the portion near the central region 63 of the end region 61 and the portion near the central region 63 of the end region 62 get over the central region 63 and enter between the central region 63 and the central portion of the curved top 25.

As described above, even if the top 25 of the bead portion 24 is curved, the elastic portion 60 is deformed so as not to form a gap between the top 25 and the frame 50, following the shape of the top 25. Therefore, the elastic portion 60 is in close contact with the top 25 and the frame 50, and the surface pressure of the top 25 becomes uniform as shown in FIG. 6C. Similarly, both the elastic portion 70-1 and the end regions 71 and 72 are deformed so as to enter between the central region 73 and the central portion of the curved top 45, and the surface pressure of the top 45 becomes uniform. In this way, the sealing property between the bead portion 24 and the frame 50 and the sealing property between the bead portion 44 and the frame 50-1 are improved.

As described above, it is desirable that the width W3 of the central region 63 is narrower than the sum of the width W1 of the end region 61 and the width W2 of the end region 62. This is because when a compressive load is applied to the end regions 61 and 62, the volume of the end regions 61 and 62 required to extend so as to fill the gap between the central region 63 and the top 25 can be secured. is there. As shown in FIG. 6B, the width of the central region 63 is narrower than the sum of the width of the end region 61 and the width of the end region 62 even in the state after fastening.

Since the elastic portion 60 is adhered to the top 25 of the bead portion 24, it is desirable that the adhesive force between the central region 63 and the top 25 is not too strong. Specifically, as shown in FIG. 6B, the compressive load due to fastening acts on the elastic portion 60, so that a part of the end regions 61 and 62 enters between the central region 63 and the top 25, and the central region It is preferable that 63 is adhered with an adhesive force such that it is peeled off from the top 25. The same applies to the elastic portion 70-1.

The elastic portion 60 may be integrally formed with the frame 50 in advance without being adhered to the top portion 25. In this case, a similar elastic portion may be integrally formed in advance on the surface of the frame 50 opposite to the surface on which the elastic portion 60 is formed. Also in this case, the surface pressure of the bead portion can be made uniform and the sealing property can be improved. Further, since the elastic portion 60 is integrally formed with the frame 50 in advance, the work of adhering the elastic portion 60 to the separator 20 becomes unnecessary, and the assembly process can be simplified. Similarly, the elastic portion 70-1 may not be adhered to the top portion 45 of the separator 40, but may be integrally formed with the frame 50-1 in advance.

For example, when the elastic portions 60-1 and 70-1 are integrally formed in advance on the frame 50-1 shown in FIG. 3, the elastic portions are formed as the separator is displaced as shown in FIG. It is considered that the positions of 60-1 and 70-1 do not shift. However, as described above, even if the separator is not misaligned, the sealing performance can be improved by making the surface pressure of the bead portion uniform. Therefore, the elastic portion formed integrally with the frame is also carried out. It is preferable to use an elastic portion as in the example.

The elastic moduli of the end regions 61 and 62 are the same, but are not limited to this, and the elastic moduli of the end regions 61 and 62 may be different as long as they are smaller than the elastic modulus of the central region 63. Therefore, the materials of the edge regions 61 and 62 may be different.

The thicknesses of the edge regions 61 and 62 and the central region 63 are substantially the same, but not limited to this. Since the end regions 61 and 62 may be extended so as to enter between the central region 63 and the top 25 so as to follow the deformation of the top 25 of the bead portion 24, the thicknesses of the end regions 61 and 62 and the central region 63 are increased. It may be different.

As shown in FIGS. 6A and the like, the shapes of the bead portions 24 and 44 are substantially symmetrical with respect to the XY plane passing through the contact surfaces of the base portions 21 and 41, but are not limited thereto. For example, the protruding height of the bead portion 24 from the base portion 21 in the −Z direction and the protruding height of the bead portion 44 from the base portion 41 in the + Z direction may be different.

In the above description, the elastic portion 60 arranged between the bead portion 24 and the frame 50 that circulates along the outer peripheral edge of the separator 20 has been described, but the bead portions 291 to 296 that surround the holes a1 to a6, respectively. An elastic portion 60 may be provided between either of them and the frame 50. Similarly, the elastic portion 70 may be provided between any of the bead portions 491 to 496 and the frame 50-1.

[First modification]
Next, a plurality of modified examples will be described. The modified example will be described with reference to the same reference numerals for the same configuration as that of the present embodiment described above. FIG. 7A is a partial cross-sectional view showing the periphery of the bead portions 24 and 44 of the single cell 2a before fastening in the first modification. FIG. 7B is a partial cross-sectional view showing the periphery of the bead portions 24 and 44 of the single cell 2a after fastening in the first modification. FIG. 7C is a graph showing the surface pressure distribution of the top 25 of the single cell 2 after fastening in the first modification.

In the fuel cell stack 1a in the first modification, elastic portions 60a and 70a-1 are adopted. The elastic portion 60a includes end regions 61a and 62a and a central region 63a. Unlike the present embodiment described above, the elastic modulus of the central region 63a is smaller than the elastic modulus of each of the end regions 61a and 62a. For example, the material in the central region 63a is a styrene-based or olefin-based thermoplastic elastomer, and the materials in the end regions 61a and 62a are urethane-based, ester-based, or amide-based thermoplastic elastomers.

In the state before fastening, the width W3a of the central region 63a is larger than the sum of the width W1a of the end region 61a and the width W2a of the end region 62a. In the first modification, each of the widths W1a and W2a is about one-eighth of the total width of the elastic portion 60a, and the width W3a is about three-quarters of the total width of the elastic portion 60a. Similarly, the elastic portion 70a-1 includes end regions 71a and 72a and a central region 73a, and has the same material, size, and shape as the end regions 61a and 62a and the central region 63a, respectively. As shown in FIG. 7B, the width of the central region 63a is larger than the sum of the width of the end region 61a and the width of the end region 62a even in the state after fastening.

When a compressive load is applied to the elastic portion 60a, the end regions 61a and 62a having a large elastic modulus are difficult to be deformed, but the central region 63a having a small elastic modulus tends to be deformed so as to extend in the X direction. However, such deformation of the central region 63a is regulated by the end regions 61a and 62a, and the central region 63a is deformed so as to bulge toward the central portion of the top 25 of the bead portion 24. In this way, the elastic portion 60a is deformed so that a gap is not formed between the top portion 25 and the frame 50, so that the surface pressure of the top portion 25 can be made uniform. Similarly, the central region 73a also extends so as to bulge toward the central portion of the curved top 45, and the surface pressure of the top 45 becomes uniform. In this way, the sealing property is improved.

Each of the widths W1a and W2a is less than one-fourth of the total width of the elastic portion 60a, and the width W3a may be one-half or more of the total width of the elastic portion 60a. Preferably, each of the widths W1a and W2a is less than one-fifth of the total width of the elastic portion 60a, and the width W3a may be three-fifths or more of the total width of the elastic portion 60a. More preferably, each of the widths W1a and W2a is less than one-sixth of the total width of the elastic portion 60a, and the width W3a may be two-thirds or more of the total width of the elastic portion 60a. .. More preferably, each of the widths W1a and W2a is less than one-seventh of the total width of the elastic portion 60a, and the width W3a may be five-sevenths or more of the total width of the elastic portion 60a. .. This is because if the width W3a is too narrow, it is not possible to secure the volume of the central region 63a for filling the gap between the central portion of the top 25 of the bead portion 24 and the frame 50.

Further, each of the widths W1a and W2a may be larger than 1/16 of the total width of the elastic portion 60a, and the width W3a may be less than 7/8 of the total width of the elastic portion 60a. If the widths W1a and W2a are too narrow, the rigidity of the end regions 61a and 62a cannot be ensured, and it is difficult to regulate the deformation of the central region 63a that tends to extend in the X direction by the end regions 61a and 62a. Because it becomes.

The elastic moduli of the end regions 61a and 62a are the same, but the elastic moduli of the end regions 61a and 62a may be different as long as they are larger than the elastic modulus of the central region 63a. The elastic portion 60a may be provided separately from the frame 50 and adhered to the top 25 of the bead portion 24, or may be integrally formed with the frame 50 in advance. The same applies to the elastic portion 70a-1. The elastic portion 60a shown in the first modification and the elastic portion 70-1 shown in the above-described embodiment may be used, or the elastic portion 70a-1 shown in the first modification and the above-described present embodiment may be used. The elastic portion 60 shown in the above may be used.

[Second modification]
FIG. 8A is a partial cross-sectional view showing the periphery of the bead portions 24 and 44 of the single cell 2b before fastening in the second modification. FIG. 8B is a partial cross-sectional view showing the periphery of the bead portions 24 and 44 of the single cell 2b after fastening in the second modification. FIG. 8C is a graph showing the surface pressure distribution of the top 25 of the single cell 2b after fastening in the second modification.

An elastic portion 60b is integrally formed in advance on one surface of the frame 50 of the single cell 2b of the fuel cell stack 1b of the second modification. The elastic portion 60b includes end regions 61b and 62b, and a central region 63. The end regions 61b and 62b are formed of the same material as the end regions 61 and 62 of this embodiment, and have the same elastic modulus. The end regions 61b and 62b extend away from the top 25 to a non-contact region. The regions of the end regions 61b and 62b that are separated from the top 25 and do not contact are larger than the width of the region that contacts the top 25. Similarly, the elastic portion 70b-1 includes end regions 71b and 72b and a central region 73, and has the same material, shape, and size as the end regions 61b and 62b and the central region 63, respectively. An elastic portion similar to the elastic portion 60b is integrally formed in advance on the surface of the frame 50 opposite to the surface on which the elastic portion 60b is provided.

The region of the end region 61b facing one end of the top 25 is an example of the first end region, and the region of the end region 61b that does not contact the top 25 is the first distance formed continuously in the first end region. It is an example of the area. The region of the end region 62b facing the other end of the top 25 is an example of the second end region, and the region of the end region 62b that does not contact the top 25 is a second portion continuously formed in the second end region. This is an example of a separation region. The region of the end region 71b facing one end of the top 45 is an example of the third end region, and the region of the end region 71b that does not contact the top 45 is the third distance formed continuously in the third end region. It is an example of the area. The region of the end region 72b facing the other end of the top 45 is an example of the fourth end region, and the region of the end region 72b that does not contact the top 45 is the fourth portion continuously formed in the fourth end region. This is an example of a separation region.

When a compressive load acts on the elastic portion 60b, the end regions 61b and 62b are compressed, and the portions of the end regions 61b and 62b near the central region 63 are the central region 63 and the top, as in the present embodiment shown in FIG. 6B. It can be deformed so as to enter between the top 25 and the surface pressure of the top 25 can be made uniform. The same applies to the elastic portion 70b-1. This improves the sealing property.

As described above, since the regions of the end regions 61b and 62b that are separated from the top 25 and do not contact are larger than the width of the region that contacts the top 25, the overall rigidity of the frame 50 and the elastic portion 60b is ensured. Has been done. Therefore, it is possible to prevent the entire frame 50 and the elastic portion 60b from bending in the state after fastening, and to secure the sealing property. The elastic portion 60b may be integrally formed in advance over the entire surface of one surface of the frame 50. As a result, the overall rigidity of the frame 50 and the elastic portion 60b can be further secured.

Further, in the second modification, although not shown, an elastic portion similar to the elastic portion 60b is integrally formed on the other surface of the frame 50. Here, when the elastic portion 60b is integrally formed only on one surface of the frame 50 and the elastic portion different from the frame 50 is provided on the other surface of the frame 50, the frame 50 and the elastic portion are provided. Warpage may occur in response to temperature changes due to the difference in thermal expansion coefficient from 60b. In the second modification, the occurrence of such a problem can be suppressed.

Since the end regions 61b and 62b extend to a region that is separated from the top 25 and does not come into contact with each other, even if the end regions 61b and 62b are fastened with the center of the central region 63 slightly offset from the center of the top 25, one end of the top 25 If the central region 63 is located between the other end and the other end, one end and the other end of the top 25 come into contact with the end regions 61b and 62b, respectively. Therefore, even in such a state, the portions of the end regions 61b and 62b near the central region 63 extend so as to enter between the central region 63 and the top 25, and the sealing property is improved.

Further, since the end region 61b is formed of the same material in both the region in contact with the top portion 25 and the region in contact with the top 25, an increase in material cost can be suppressed and an increase in manufacturing cost is suppressed. The same applies to the end regions 62b, 71b, and 72b.

The elastic portion 60b may be formed on one surface of the frame 50 over the entire surface, or the elastic portion 60b is provided so as to expose one surface of the frame 50 at a portion away from the bead portion 24. There may be parts that are not covered.

[Third variant]
FIG. 9A is a partial cross-sectional view showing the periphery of the bead portions 24 and 44 of the single cell 2c before fastening in the third modification. FIG. 9B is a partial cross-sectional view showing the periphery of the bead portions 24 and 44 of the single cell 2c after fastening in the third modification. FIG. 9C is a graph showing the surface pressure distribution of the top 25 of the single cell 2c after fastening in the third modification.

An elastic portion 60c is formed integrally with the frame 50 over the entire surface on one surface of the frame 50 of the single cell 2c of the fuel cell stack 1c of the third modification. The elastic portion 60c includes end regions 61a and 62a, a central region 63a, and separation regions 64c and 65c. The separation regions 64c and 65c are formed of the same material as the central region 63a, and the elastic moduli of the separation regions 64c and 65c are the same as the elastic modulus of the central region 63a. Each of the separation regions 64c and 65c is formed wider than the total width of the central region 63a and the end regions 61a and 62a without facing the top 25. Similarly, the elastic portion 70c-1 includes end regions 71a and 72a, a central region 73a, and a separation region 74c and 75c, the end regions 61a and 62a, the central region 63a, and the separation regions 64c and 65c, respectively, and the material. The size and shape are the same. The separation regions 64c and 65c are examples of the first and second separation regions, respectively. The separation regions 74c and 75c are examples of the third and fourth separation regions, respectively.

In the third modification as well, as in the first modification, the end regions 61a and 62a regulate the deformation of the central region 63a in the X direction, and the central region 63a is the center of the top 25 of the bead portion 24. Since it is deformed so as to rise toward the part, the sealing property is improved. The same applies to the elastic portion 70c-1.

Also in the third modification, since the separation regions 64c and 65c that do not contact the top 25 are formed wide, the rigidity of the entire frame 50 and the elastic portion 60c can be ensured. Further, although not shown, since an elastic portion similar to the elastic portion 60c is formed on the other surface of the frame 50, the occurrence of warpage can be suppressed as in the second modification.

Further, since the separation regions 64c and 65c are formed of the same material as the central region 63a, an increase in material cost can be suppressed, and an increase in manufacturing cost is suppressed. The same applies to the separation regions 74c and 75c.

The elastic portion 60c may be formed on one surface of the frame 50 over the entire surface, or the elastic portion 60c is provided so as to expose one surface of the frame 50 at a portion away from the bead portion 24. There may be parts that are not covered.

The elastic portion 60c shown in the third modification and the elastic portion 70b-1 shown in the second modification may be used, or the elastic portion 70c-1 and the second modification shown in the third modification may be used. The elastic portion 60b may be used.

[Fourth variant]
FIG. 10A is a partial cross-sectional view showing the periphery of the bead portions 24 and 44 of the single cell 2d before fastening in the fourth modification. FIG. 10B is a partial cross-sectional view showing the periphery of the bead portions 24 and 44 of the single cell 2d after fastening in the fourth modification. FIG. 10C is a graph showing the surface pressure distribution of the top 25 of the single cell 2d after fastening in the fourth modification.

An elastic portion 60d is formed integrally with the frame 50 over the entire surface on one surface of the frame 50 of the single cell 2d of the fuel cell stack 1d of the fourth modification. The elastic portion 60d includes end regions 61d and 62d and a central region 63a. One end of the end region 61d abuts on one end of the top 25 of the bead portion 24, one end of the end region 62d abuts on the other end of the top 25 of the bead portion 24, but the end regions 61d and 62d respectively abut on the top of the bead portion 24. It extends away from 25 to a non-contact area. The regions of the end regions 61d and 62d that do not contact the top 25 are formed wider than the regions that contact the top 25. Similarly, the elastic portion 70d-1 includes end regions 71d and 72d and a central region 73a, and has the same material, size, and shape as the end regions 61d and 62d and the central region 63a, respectively.

The region of the end region 61d facing one end of the top 25 is an example of the first end region, and the region of the end region 61d that does not contact the top 25 is an example of the first separation region. The region of the end region 62d facing the other end of the top 25 is an example of the second end region, and the region of the end region 62d that does not contact the top 25 is an example of the second separation region. The region of the end region 71d facing one end of the top 45 is an example of the third end region, and the region of the end region 71d that does not contact the top 45 is an example of the third separation region. The region of the end region 72d facing the other end of the top 45 is an example of the fourth end region, and the region of the end region 72d that does not contact the top 45 is an example of the fourth separation region.

In the fourth modification as well, as in the first modification, the end regions 61d and 62d regulate the deformation of the central region 63a in the X direction, and the central region 63a is the center of the top 25 of the bead portion 24. Since it is deformed so as to protrude toward the portion, the sealing property is improved. The same applies to the elastic portion 70d-1.

Since the end regions 61d and 62d having a elastic modulus larger than that of the central region 63a are formed to be wide, the rigidity of the entire frame 50 and the elastic portion 60d can be ensured. Further, although not shown, an elastic portion similar to the elastic portion 60d is formed on the other surface of the frame 50. Therefore, the occurrence of warpage can be suppressed as in the second modification.

Further, since the end region 61d is formed of the same material in both the region in contact with the top portion 25 and the region in contact with the top 25, an increase in material cost can be suppressed and an increase in manufacturing cost is suppressed. The same applies to the end regions 62d, 71d, and 72d.

The elastic portion 60d may be formed on one surface of the frame 50 over the entire surface, or the elastic portion 60d is provided so as to expose one surface of the frame 50 at a portion away from the bead portion 24. There may be parts that are not covered.

The elastic portion 60d shown in the fourth modification and the elastic portion 70b-1 shown in the second modification or the elastic portion 70c-1 shown in the third modification may be used. The elastic portion 70d-1 shown in the fourth modification and the elastic portion 60b shown in the second modification or the elastic portion 60c shown in the third modification may be used.

Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the specific embodiments, and various modifications and variations are made within the scope of the gist of the present invention described in the claims. It can be changed.

1,1a, 1b, 1c, 1d Fuel cell stack 2,2a, 2b, 2c, 2d Single cell 2-1 Single cell (other single cell)
10 Membrane electrode gas diffusion layer joint body (first membrane electrode gas diffusion layer joint body)
20 Anode separator (first separator)
40 Cathode separator (second separator)
21 base (1st base)
41 base (second base)
24 bead part (1st bead part)
44 bead part (second bead part)
25 Top (1st top)
45 Top (2nd top)
26 Side (1st side)
27 side (second side)
46 side (third side)
47 side (4th side)
50 frames (1st frame)
50-1 frame (second frame)
60, 60a, 60b, 60c, 60d Elastic part (first elastic part)
70-1, 70a-1, 70b-1, 70c-1, 70d-1 Elastic part (second elastic part)
61, 61a end area (first end area)
62, 62a end area (second end area)
71, 71a end area (third end area)
72, 72a end area (fourth end area)
61b, 61d end region (first end region, first separation region)
62b, 62d end region (second end region, second separation region)
71b, 71d end regions (third end region, third separation region)
72b, 72d end region (4th end region, 4th separation region)
64c separation area (first separation area)
65c separation area (second separation area)
74c separation area (third separation area)
75c separation area (fourth separation area)
63, 63a Central area (first central area)
73, 73a Central region (second central region)

Claims (20)

In a fuel cell stack in which multiple single cells are stacked
At least one of the plurality of single cells includes a first membrane electrode gas diffusion layer junction, a first frame supporting the first membrane electrode gas diffusion layer junction, and the first membrane electrode gas diffusion layer junction. Includes a first separator, which faces the first frame,
The first separator includes a first base portion and a first bead portion that protrudes from the first base portion toward the first frame and has a width along the first direction.
The first bead portion is a first top portion located closer to the first frame than the first base portion, and a continuous first portion between one end of the first top portion in the first direction and the first base portion. Includes one side and a second side that is continuous between the other end of the first apex in the first direction and the first base.
A first elastic portion is provided between the first top portion and the first frame.
The first elastic portion is located between the first and second end regions and the first and second end regions that abut one end of the first top portion and the other end of the first top portion, respectively. Including the central area,
A fuel cell stack in which the elastic modulus of the first central region is larger than the elastic modulus of each of the first and second end regions. In a fuel cell stack in which multiple single cells are stacked
At least one of the plurality of single cells includes a first membrane electrode gas diffusion layer junction, a first frame supporting the first membrane electrode gas diffusion layer junction, and the first membrane electrode gas diffusion layer junction. Includes a first separator, which faces the first frame,
The first separator includes a first base portion and a first bead portion that protrudes from the first base portion toward the first frame and has a width along the first direction.
The first bead portion is a first top portion located closer to the first frame than the first base portion, and a continuous first portion between one end of the first top portion in the first direction and the first base portion. Includes one side and a second side that is continuous between the other end of the first apex in the first direction and the first base.
A first elastic portion is provided between the first top portion and the first frame.
The first elastic portion is located between the first and second end regions and the first and second end regions that abut one end of the first top portion and the other end of the first top portion, respectively. Including the central area,
A fuel cell stack in which the elastic modulus of the first central region is smaller than the elastic modulus of each of the first and second end regions. The fuel cell stack according to claim 1, wherein the width of the first central region is narrower than the total width of the first and second end regions. The fuel cell stack according to claim 2, wherein the width of the first central region is wider than the total width of the first and second end regions. The fuel cell stack according to any one of claims 1 to 4, wherein the first elastic portion is integrally formed with the first frame in advance. The fuel cell stack according to claim 5, wherein the first elastic portion includes a first separated region continuously formed in the first end region and separated from the first top portion. The fuel cell stack according to claim 6, wherein the width of the first separation region is wider than the total width of the first and second end regions and the first central region. The fuel cell stack according to claim 6 or 7, wherein the first separation region is formed of the same material as the first end region. The fuel cell stack according to claim 6 or 7, wherein the first separation region is formed of the same material as the first central region. The fuel cell stack according to any one of claims 5 to 9, wherein the first elastic portion includes a second separated region continuously formed in the second end region and separated from the first top portion. The fuel cell stack according to claim 10, wherein the width of the second separation region is wider than the total width of the first and second end regions and the first central region. The fuel cell stack according to claim 10 or 11, wherein the second separation region is formed of the same material as the second end region. The fuel cell stack according to claim 10 or 11, wherein the second separation region is formed of the same material as the first central region. The at least one of the plurality of single cells includes the first film electrode gas diffusion layer junction and the second separator facing the first separator on the opposite side of the first frame.
The other single cell adjacent to the at least one of the plurality of single cells includes a second film electrode gas diffusion layer junction and a second frame supporting the second membrane electrode gas diffusion layer junction.
The second film electrode gas diffusion layer joint and the second frame face the second separator.
The second separator includes a second base portion that abuts on the first base portion, and a second bead portion that protrudes from the second base portion toward the second frame and has a width along the first direction. ,
The second bead portion is a second top portion located closer to the second frame than the second base portion, and a continuous second portion between one end of the second top portion in the first direction and the second base portion. Includes three side portions and a fourth side portion that is continuous between the other end of the second apex in the first direction and the second base.
A second elastic portion is provided between the second top portion and the second frame.
The second elastic portion is located between the third and fourth end regions and the third and fourth end regions, which are in contact with one end of the second top and the other end of the second top, respectively. Including the central area,
The fuel cell stack according to any one of claims 1 to 13, wherein the elastic modulus of the second central region is larger than the elastic modulus of each of the third and fourth end regions. The at least one of the plurality of single cells includes the first film electrode gas diffusion layer junction and the second separator facing the first separator on the opposite side of the first frame.
The other single cell adjacent to the at least one of the plurality of single cells includes a second film electrode gas diffusion layer junction and a second frame supporting the second membrane electrode gas diffusion layer junction.
The second film electrode gas diffusion layer joint and the second frame face the second separator.
The second separator includes a second base portion that abuts on the first base portion, and a second bead portion that protrudes from the second base portion toward the second frame and has a width along the first direction. ,
The second bead portion is a second top portion located closer to the second frame than the second base portion, and a continuous second portion between one end of the second top portion in the first direction and the second base portion. Includes three side portions and a fourth side portion that is continuous between the other end of the second apex in the first direction and the second base.
A second elastic portion is provided between the second top portion and the second frame.
The second elastic portion is located between the third and fourth end regions and the third and fourth end regions, which are in contact with one end of the second top and the other end of the second top, respectively. Including the central area,
The fuel cell stack according to any one of claims 1 to 13, wherein the elastic modulus of the second central region is smaller than the elastic modulus of each of the third and fourth end regions. The fuel cell stack according to claim 14, wherein the width of the second central region is narrower than the total width of the third and fourth end regions. The fuel cell stack according to claim 15, wherein the width of the second central region is wider than the total width of the third and fourth end regions. The fuel cell stack according to any one of claims 14 to 17, wherein the second elastic portion is integrally formed with the second frame in advance. The fuel cell stack according to claim 18, wherein the second elastic portion includes a third separated region which is continuously formed in the third end region and is separated from the second top portion. The fuel cell stack according to claim 18 or 19, wherein the second elastic portion includes a fourth separated region continuously formed in the fourth end region and separated from the second top portion.

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