Fuel battery

Abstract

To provide a fuel battery which can be easily processed and can improve the diffusion efficiency of gas into a gas diffusion layer.SOLUTION: A fuel battery includes: a gas diffusion layer; and a separator having a gas flow path for supplying gas to the gas diffusion layer and disposed in contact with the gas diffusion layer so as to face the gas diffusion layer. The gas diffusion layer includes a gas flow path forming part that forms a part of the gas flow path along a flow path direction that is a direction in which the gas flows through the gas flow path. The gas flow path forming part includes a first part and a second part adjacent to the first part in the flow path direction, and an amount of protrusion of the first part to the gas flow path is larger than an amount of protrusion of the second part to the gas flow path.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to fuel cells. [Background technology]

[0002] Patent Document 1 discloses a fuel cell in which a throttle portion that reduces the cross-sectional area of the flow path is arranged in the separator flow path. The technology in Patent Document 1 improves the diffusion efficiency of the reactant gas flowing through the flow path to the cathode diffusion layer by arranging the throttle portion in the flow path. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-102413 Summary of the Invention [Problem to be solved by the invention]

[0004] Separators with constricted gas flow paths have a complex shape, making them difficult to process. Therefore, there is a need for fuel cells that are easier to process and can improve the diffusion efficiency of gas flowing through the gas flow paths to the gas diffusion layer. [Means for solving the problem]

[0005] The present disclosure can be realized in the following forms.

[0006] (1) According to one aspect of the present disclosure, there is provided a fuel cell comprising: a gas diffusion layer; and a separator having a gas flow path for supplying gas to the gas diffusion layer, the separator facing the gas diffusion layer and being in contact with the gas diffusion layer, the gas diffusion layer comprising a gas flow path forming portion that forms a part of the gas flow path along a flow path direction in which the gas flows through the gas flow path, the gas flow path forming portion comprising a first portion and a second portion adjacent to the first portion in the flow path direction, wherein the amount of protrusion of the first portion into the gas flow path is greater than the amount of protrusion of the second portion into the gas flow path. In this fuel cell, the gas diffusion layer having the first and second portions can be fabricated more easily than when a separator having a complex shape is fabricated, and the diffusion efficiency of the gas flowing through the gas flow path to the gas diffusion layer can be improved in the first portion. (2) In the fuel cell of the above aspect, the compressibility of the gas diffusion layer in the first portion may be lower than the compressibility of the gas diffusion layer in the second portion. According to this configuration of the fuel cell, the efficiency of diffusion of the gas flowing through the gas flow passage into the gas diffusion layer can be further improved. (3) In the fuel cell of the above configuration, the area of the first portion of the gas flow path forming portion upstream of the intermediate position in the flow path direction may be larger than the area of the first portion of the gas flow path forming portion downstream of the intermediate position. According to this configuration of the fuel cell, the power generation performance can be further improved on the upstream side of the intermediate position of the gas flow passage. (4) In the fuel cell of the above configuration, the area of the first portion of the gas flow path forming portion downstream of the intermediate position in the flow path direction may be larger than the area of the first portion of the gas flow path forming portion upstream of the intermediate position. According to this configuration of the fuel cell, it is possible to further improve the power generation performance downstream of the intermediate position of the gas flow passage. (5) In the fuel cell of the above aspect, the separator may include a plurality of the gas flow paths arranged parallel to each other, the gas diffusion layer may include a plurality of the gas flow path forming portions arranged parallel to each other, each of the gas flow path forming portions forming a part of a different gas flow path, and the first portions of each of the gas flow path forming portions may be aligned in a direction approximately perpendicular to the flow path direction within the plane of the gas diffusion layer. According to this configuration of the fuel cell, it is possible to align the positions in all the gas flow paths where the gas diffusion efficiency to the gas diffusion layer is high in the flow path direction. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a cross-sectional view showing a schematic configuration of a fuel cell. [Figure 2] View of the cathode diffusion layer from the +Z direction. [Figure 3] FIG. 3 is a cross-sectional view of the cathode diffusion layer and the cathode separator taken along the line III-III in FIG. 2. [Figure 4] FIG. 4 is a cross-sectional view of the cathode diffusion layer and the cathode separator taken along the line IV-IV in FIG. 2. [Figure 5] 5A to 5C are diagrams illustrating a method for processing a cathode diffusion layer. [Figure 6] FIG. [Figure 7] FIG. 10 is a view of the cathode diffusion layer in the second embodiment as viewed from the +Z direction. [Figure 8] FIG. 11 is a view of the cathode diffusion layer in the third embodiment as viewed from the +Z direction. DETAILED DESCRIPTION OF THE INVENTION

[0008] A. First embodiment: FIG. 1 is a cross-sectional view showing the schematic configuration of a fuel cell 100, which is a polymer electrolyte fuel cell. FIG. 1 shows arrows representing mutually orthogonal X, Y, and Z directions. The X, Y, and Z directions in FIG. 1 and the X, Y, and Z directions in other figures indicate the same directions. When specifying a direction, positive and negative signs are used in combination to indicate the direction, with "+" indicating the positive direction indicated by the arrow and "-" indicating the negative direction opposite to the direction indicated by the arrow.

[0009] The fuel cell 100 includes a membrane electrode assembly (MEA) 10, a cathode diffusion layer 50, an anode diffusion layer 60, a cathode separator 70, and an anode separator 80.

[0010] The membrane electrode assembly 10 includes an electrolyte membrane 20, a cathode catalyst layer 30, and an anode catalyst layer 40. The electrolyte membrane 20 is an ion exchange membrane having proton conductivity and formed from a solid polymer material, for example, a fluorine-based resin containing perfluorocarbon sulfonic acid, and exhibits good electrical conductivity in a wet state.

[0011] The cathode catalyst layer 30 and the anode catalyst layer 40 are formed by coating conductive particles, such as carbon particles, carrying a catalyst such as platinum or a platinum alloy, with a proton-conductive polymer electrolyte. The cathode catalyst layer 30 is formed on one side of the electrolyte membrane 20, and the anode catalyst layer 40 is formed on the other side of the electrolyte membrane 20. In this embodiment, the cathode catalyst layer 30 is formed on the surface of the electrolyte membrane 20 facing the +Z direction, and the anode catalyst layer 40 is formed on the surface of the electrolyte membrane 20 facing the -Z direction.

[0012] The cathode diffusion layer 50 and the anode diffusion layer 60 are made of gas-permeable and conductive materials such as carbon cloth or carbon paper. The cathode diffusion layer 50 is formed on the surface of the cathode catalyst layer 30 opposite to the surface that contacts the electrolyte membrane 20. The anode diffusion layer 60 is formed on the surface of the anode catalyst layer 40 opposite to the surface that contacts the electrolyte membrane 20. Hereinafter, when the cathode diffusion layer 50 and the anode diffusion layer 60 are referred to interchangeably, they will be referred to as gas diffusion layers.

[0013] The cathode separator 70 and the anode separator 80 are made of gas-blocking and electrically conductive materials, such as dense carbon made by compressing carbon particles to make them gas-impermeable, or press-molded metal materials such as stainless steel or titanium steel. Hereinafter, when the cathode separator 70 and the anode separator 80 are referred to interchangeably, they will be referred to as separators.

[0014] The cathode separator 70 is disposed in contact with the cathode diffusion layer 50 on the surface of the cathode diffusion layer 50 opposite to the surface that contacts the cathode catalyst layer 30. The cathode separator 70 has a plurality of grooves 71 that open to the surface facing the cathode diffusion layer 50. In this embodiment, the plurality of grooves 71 are arranged parallel to one another along the Y direction. The grooves 71 form part of a cathode gas flow channel 75 of the cathode separator 70. Air is supplied to the cathode gas flow channel 75 as an oxidant gas. The cathode gas flow channel 75 supplies air to the cathode diffusion layer 50.

[0015] The anode separator 80 is disposed in contact with the anode diffusion layer 60 on the surface of the anode diffusion layer 60 opposite to the surface that contacts the anode catalyst layer 40. The anode separator 80 has a plurality of grooves 81 that open to the surface facing the anode diffusion layer 60. In this embodiment, the grooves 81 are arranged parallel to one another along the Y direction. The grooves 81 form part of an anode gas flow channel 85 of the anode separator 80. Hydrogen is supplied to the anode gas flow channel 85 as a reactant gas. The anode gas flow channel 85 supplies hydrogen to the anode diffusion layer 60. Hereinafter, when the cathode gas flow channel 75 and the anode gas flow channel 85 are referred to interchangeably, they will be referred to as the gas flow channel. The direction in which the oxidant gas flows through the cathode gas flow channel 75 and the direction in which the reactant gas flows through the anode gas flow channel 85 will be referred to as the flow channel direction. In this embodiment, the flow channel direction is the +Y direction.

[0016] FIG. 2 is a view of the cathode diffusion layer 50 as viewed from the +Z direction. The cathode diffusion layer 50 includes multiple cathode gas channel formation portions 51. The multiple cathode gas channel formation portions 51 are arranged parallel to one another along the Y direction on the surface of the cathode diffusion layer 50 that contacts the cathode separator 70. The cathode gas channel formation portions 51 form part of the cathode gas channel 75. Specifically, one cathode gas channel formation portion 51 and one groove 71 provided in the cathode separator 70 form one cathode gas channel 75. In other words, each cathode gas channel formation portion 51 forms part of a different cathode gas channel 75. In FIG. 2, the channel direction, i.e., the direction in which the oxidant gas flows, is indicated by an outline arrow.

[0017] The cathode gas flow channel forming portion 51 includes a first portion 52 and a second portion 53. In FIG. 2, the first portion 52 and the second portion 53 are hatched differently to clearly show the first portion 52 and the second portion 53. The second portion 53 is provided adjacent to the first portion 52 in the flow channel direction. In the example shown in FIG. 2, the cathode diffusion layer 50 includes three cathode gas flow channel forming portions 51, and each cathode gas flow channel forming portion 51 includes two first portions 52 and three second portions 53. The first portions 52 of each cathode gas flow channel forming portion 51 are aligned in a direction substantially perpendicular to the flow channel direction within the plane of the cathode diffusion layer 50. In the example shown in FIG. 2, the first portions 52 of each cathode gas flow channel forming portion 51 are aligned in the X direction.

[0018] FIG. 3 is a cross-sectional view of the cathode diffusion layer 50 and the cathode separator 70 taken along the line III-III in FIG. 2 . FIG. 4 is a cross-sectional view of the cathode diffusion layer 50 and the cathode separator 70 taken along the line IV-IV in FIG. 2 . FIG. 3 is a cross-sectional view including the first portion 52, and FIG. 4 is a cross-sectional view including the second portion 53. As shown in FIGS. 3 and 4 , the first portion 52 protrudes into the cathode gas flow channel 75 by a larger amount than the second portion 53 protrudes into the cathode gas flow channel 75. Here, the amount of protrusion into the cathode gas flow channel 75 refers to the distance in the Z direction between the position of the reference plane S, where the surface where the cathode diffusion layer 50 and the cathode separator 70 contact each other, and the position of the first portion 52 or the second portion 53 located furthest in the +Z direction. Protrusion into the gas flow channel is also referred to as bending into the gas flow channel.

[0019] FIG. 5 is a diagram illustrating a method for processing the cathode diffusion layer 50. FIG. 6 is a perspective view of the first roller 110 shown in FIG. 5. The cathode diffusion layer 50 is processed, for example, by compressing the material of the cathode diffusion layer 50, such as carbon cloth, between two rollers. The first roller 110 and the second roller 120 shown in FIG. 5 are cylindrical rollers with axes along the X direction. The cathode diffusion layer 50 is disposed between the first roller 110 and the second roller 120 in the Z direction and moves in the −Y direction relative to the first roller 110 and the second roller 120 as the first roller 110 and the second roller 120 rotate. The first roller 110 has grooves 111 formed on its outer circumferential surface along the X direction. The second roller 120 has no grooves formed on its outer circumferential surface. The cathode diffusion layer 50 is compressed by the first roller 110 and the second roller 120, forming a low-compression portion 131 and a high-compression portion 132 with different compression rates in the cathode diffusion layer 50. The low-compression portion 131 is a portion of the cathode diffusion layer 50 with a lower compression rate than the high-compression portion 132. The low-compression portion 131 is formed along the X direction in a portion of the cathode diffusion layer 50 that contacts the grooves 111 of the first roller 110. The high-compression portion 132 is formed in a portion of the cathode diffusion layer 50 that does not contact the grooves 111 of the first roller 110. The low-compression portion 131 corresponds to the first portion 52 of the cathode gas flow channel forming portion 51 shown in FIG. 2 , and the high-compression portion 132 corresponds to the second portion 53 of the cathode gas flow channel forming portion 51. That is, the compressibility of the cathode diffusion layer 50 in the first portion 52 is lower than the compressibility of the cathode diffusion layer 50 in the second portion 53.

[0020] Here, a high compression ratio of the cathode diffusion layer 50 means that the cathode diffusion layer 50 is crushed to a large extent, and a low compression ratio of the cathode diffusion layer 50 means that the cathode diffusion layer 50 is crushed to a small extent. For example, if the cathode diffusion layer 50 is made of a material in which carbon fibers are bound with a resin binder, the areas with a high compression ratio have fewer gaps between the carbon fibers, while the areas with a low compression ratio have more gaps between the carbon fibers. In other words, the areas with a high compression ratio have low gas permeability, and the areas with a low compression ratio have high gas permeability.

[0021] The anode diffusion layer 60 has a plurality of anode gas flow channel formation portions. The anode gas flow channel formation portions are formed in the anode diffusion layer 60 in the same manner as the cathode gas flow channel formation portions 51 in the cathode diffusion layer 50. The shape of the anode gas flow channel formation portions is the same as that of the cathode gas flow channel formation portions 51, and therefore is not shown in the drawings.

[0022] Similar to the cathode gas channel forming portion 51 shown in FIG. 2 , the multiple anode gas channel forming portions are arranged parallel to one another along the Y direction on the surface of the anode diffusion layer 60 that comes into contact with the anode separator 80. The anode gas channel forming portions form part of the anode gas channel 85. Each anode gas channel forming portion forms part of a different anode gas channel 85. The anode gas channel forming portion includes a first portion 52 and a second portion 53. The first portions 52 of each anode gas channel forming portion are aligned in a direction substantially perpendicular to the channel direction within the plane of the anode diffusion layer 60. The first portions 52 of the anode gas channel forming portions protrude into the anode gas channel 85 by a greater amount than the second portions 53. The anode diffusion layer 60 is processed in the same manner as the cathode diffusion layer 50. The compressibility of the anode diffusion layer 60 in the first portion 52 is lower than the compressibility of the anode diffusion layer 60 in the second portion 53. Hereinafter, when there is no need to distinguish between the cathode gas channel formation portion 51 and the anode gas channel formation portion, they will be referred to as the gas channel formation portion.

[0023] According to the fuel cell 100 of the first embodiment described above, the gas diffusion layer includes a gas flow path forming portion that forms a part of the gas flow path, and the gas flow path forming portion includes a first portion 52 and a second portion 53. The first portion 52 protrudes into the gas flow path by a larger amount than the second portion 53. Therefore, the pressure loss of the gas flowing through the gas flow path in the first portion 52 is larger than the pressure loss in the second portion 53, and the penetration of the gas into the gas diffusion layer is promoted in the first portion 52. Therefore, the diffusion efficiency of the gas flowing through the gas flow path into the gas diffusion layer can be improved in the first portion 52. The gas diffusion layer is processed by compressing the material of the gas diffusion layer with a first roller 110 having grooves and a second roller 120 without grooves. Therefore, a fuel cell 100 with high diffusion efficiency of the gas flowing through the gas flow path into the gas diffusion layer can be produced more easily than when processing a separator with a complex shape.

[0024] In this embodiment, the compression ratio of the gas diffusion layer in the first portion 52 is lower than the compression ratio of the gas diffusion layer in the second portion 53. Therefore, the gas permeability of the gas flowing through the gas flow path to the gas diffusion layer in the first portion 52 is higher than the gas permeability of the gas diffusion layer in the second portion 53. Therefore, the diffusion efficiency of the gas flowing through the gas flow path to the gas diffusion layer can be further improved.

[0025] In this embodiment, the separator includes multiple gas flow paths arranged parallel to one another, and the gas diffusion layer includes multiple gas flow path forming portions arranged parallel to one another, each forming a part of a different gas flow path. The first portions 52 of the gas flow path forming portions are aligned in a direction substantially perpendicular to the flow path direction within the plane of the gas diffusion layer. This allows all gas flow paths to be aligned at positions where gas diffusion efficiency to the gas diffusion layer is high in the flow path direction.

[0026] B. Second embodiment: In the second embodiment, the positions of the first portion 52 and the second portion 53 of the gas flow channel forming portion are different from those of the first embodiment. The configuration of each portion of the fuel cell 100 other than the gas flow channel forming portion is the same as that of the first embodiment.

[0027] FIG. 7 is a view of a cathode diffusion layer 50b according to the second embodiment, viewed from the +Z direction. In the second embodiment, the first portion 52 and the second portion 53 of the cathode gas flow channel formation portion 51b are arranged such that the area of the first portion 52 in the cathode gas flow channel formation portion 51b upstream of a middle position C in the flow channel direction is larger than the area of the first portion 52 in the cathode gas flow channel formation portion 51b downstream of the middle position C. Here, the middle position C is a position that equally divides the cathode gas flow channel formation portion 51b in the flow channel direction. The upstream side in the flow channel direction is the −Y side of the middle position C, and the downstream side in the flow channel direction is the +Y side of the middle position C. When the cathode gas flow channel formation portion 51b includes multiple first portions 52, the area of the first portions 52 refers to the total area of all of the first portions 52. The first portion 52 and the second portion 53 may be arranged such that the density of the first portion 52 in the cathode gas flow path forming portion 51b upstream of the intermediate position C is higher than the density of the first portion 52 in the cathode gas flow path forming portion 51b downstream of the intermediate position C.

[0028] Similar to the first portion 52 and the second portion 53 of the cathode gas flow channel forming portion 51b, the first portion 52 and the second portion 53 of the anode gas flow channel forming portion are arranged such that the area of the first portion 52 in the anode gas flow channel forming portion upstream of the intermediate position in the flow channel direction is larger than the area of the first portion 52 in the anode gas flow channel forming portion downstream of the intermediate position in the flow channel direction. The anode gas flow channel forming portion is not shown. When the anode gas flow channel forming portion includes multiple first portions 52, the area of the first portions 52 refers to the total area of all the first portions 52. The first portion 52 and the second portion 53 may be arranged such that the density of the first portions 52 in the anode gas flow channel forming portion upstream of the intermediate position is higher than the density of the first portions 52 in the anode gas flow channel forming portion downstream of the intermediate position.

[0029] The upstream side of the cathode gas flow channel 75 has a higher oxygen concentration than the downstream side, and the amount of water produced by the electrochemical reaction between the reactant gas and the oxidant gas is smaller, so the upstream side has higher power generation performance than the downstream side. According to the fuel cell 100 of the second embodiment, the area of the first portion 52 in the cathode gas flow channel formation section 51b upstream of the intermediate position C in the flow channel direction is larger than the area of the first portion 52 in the cathode gas flow channel formation section 51b downstream of the intermediate position C, so the power generation performance of the cathode gas flow channel 75 upstream of the intermediate position C can be further improved.

[0030] The upstream side of the anode gas flow channel 85 has a higher hydrogen concentration than the downstream side, and therefore has higher power generation performance than the downstream side. In the fuel cell 100 of the second embodiment, the area of the first portion 52 in the anode gas flow channel formation section upstream of the intermediate position in the flow channel direction is larger than the area of the first portion 52 in the anode gas flow channel formation section downstream of the intermediate position in the flow channel direction, thereby further improving the power generation performance upstream of the intermediate position in the anode gas flow channel 85.

[0031] C. Third embodiment: In the third embodiment, the positions of the first portion 52 and the second portion 53 of the gas flow channel forming portion are different from those of the first embodiment. The configuration of each portion of the fuel cell 100 other than the gas flow channel forming portion is the same as that of the first embodiment.

[0032] 8 is a view of a cathode diffusion layer 50c according to the third embodiment, viewed from the +Z direction. In the third embodiment, the first portions 52 and second portions 53 of the cathode gas flow channel forming portion 51c are arranged such that the area of the first portions 52 in the cathode gas flow channel forming portion 51c downstream of an intermediate position C in the flow channel direction is larger than the area of the first portions 52 in the cathode gas flow channel forming portion 51c upstream of the intermediate position C. When the cathode gas flow channel forming portion 51c includes a plurality of first portions 52, the area of the first portions 52 refers to the total area of all the first portions 52. Note that the first portions 52 and the second portions 53 may be arranged such that the density of the first portions 52 in the cathode gas flow channel forming portion 51c upstream of the intermediate position C is higher than the density of the first portions 52 in the cathode gas flow channel forming portion 51c downstream of the intermediate position C.

[0033] Similar to the first portion 52 and the second portion 53 of the cathode gas flow channel forming portion 51c, the first portion 52 and the second portion 53 of the anode gas flow channel forming portion are arranged such that the area of the first portion 52 in the anode gas flow channel forming portion downstream of the intermediate position in the flow channel direction is larger than the area of the first portion 52 in the anode gas flow channel forming portion upstream of the intermediate position in the flow channel direction. The anode gas flow channel forming portion is not shown. When the anode gas flow channel forming portion includes multiple first portions 52, the area of the first portions 52 refers to the total area of all the first portions 52. The first portion 52 and the second portion 53 may be arranged such that the density of the first portions 52 in the anode gas flow channel forming portion upstream of the intermediate position is higher than the density of the first portions 52 in the anode gas flow channel forming portion downstream of the intermediate position.

[0034] In the fuel cell 100 of the third embodiment, the area of the first portion 52 in the cathode gas flow channel formation section 51c downstream of the intermediate position C in the flow channel direction is larger than the area of the first portion 52 in the cathode gas flow channel formation section 51c upstream of the intermediate position C. This further improves the power generation performance downstream of the intermediate position C of the cathode gas flow channel 75.

[0035] In this embodiment, the area of the anode gas flow channel formation portion downstream of the intermediate position in the flow channel direction of the first portion 52 is larger than the area of the anode gas flow channel formation portion upstream of the intermediate position in the flow channel direction of the first portion 52. This further improves the power generation performance downstream of the intermediate position of the anode gas flow channel 85.

[0036] D. Other Embodiments: (D-1) In the above embodiment, the compressibility of the gas diffusion layer in the first portion 52 is lower than the compressibility of the gas diffusion layer in the second portion 53. In contrast, the compressibility of the gas diffusion layer in the first portion 52 does not have to be lower than the compressibility of the gas diffusion layer in the second portion 53.

[0037] (D-2) In the above embodiment, the separator has multiple gas flow channels and the gas diffusion layer has multiple gas flow channel formation portions. In contrast, the separator only needs to have at least one gas flow channel. Also, the gas diffusion layer only needs to have at least one gas flow channel formation portion.

[0038] (D-3) In the above embodiment, the multiple gas flow paths are arranged parallel to one another. Furthermore, the multiple gas flow path forming portions are arranged parallel to one another. In contrast, the gas flow paths and the gas flow path forming portions need only be arranged so that the separator and the gas diffusion layer come into contact with each other to form the gas flow paths. The multiple gas flow paths do not have to be arranged parallel to one another, and the multiple gas flow path forming portions do not have to be arranged parallel to one another.

[0039] (D-4) In the first embodiment, the gas flow path forming portion includes two first portions 52 and three second portions 53. In contrast, it is sufficient for the gas flow path forming portion to include at least one first portion 52 and at least one second portion 53.

[0040] (D-5) In the above embodiment, both the cathode diffusion layer 50 and the anode diffusion layer 60 have a gas flow channel formation portion including the first portion 52 and the second portion 53. Alternatively, only one of the cathode diffusion layer 50 and the anode diffusion layer 60 may have a gas flow channel formation portion including the first portion 52 and the second portion 53. For example, if only the cathode diffusion layer 50 has a cathode gas flow channel formation portion 51 including the first portion 52 and the second portion 53, the amount by which the anode gas flow channel formation portion of the anode diffusion layer 60 protrudes into the anode gas flow channel 85 may be constant regardless of the position in the flow channel direction.

[0041] (D-6) In the above embodiment, the gas diffusion layer is processed by compressing the material of the gas diffusion layer, such as carbon cloth, with two rollers. In contrast, the gas diffusion layer may be processed so that the amount of protrusion of the first portion 52 into the gas flow path is greater than the amount of protrusion of the second portion 53 into the gas flow path, and the processing method is not limited to the above method.

[0042] The present disclosure is not limited to the above-described embodiments and can be realized in various configurations without departing from the spirit thereof. For example, the technical features in the embodiments corresponding to the technical features in each aspect described in the Summary of the Invention section can be appropriately replaced or combined to solve some or all of the above-described problems or achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted. [Explanation of symbols]

[0043] 10... membrane electrode assembly, 20... electrolyte membrane, 30... cathode catalyst layer, 40... anode catalyst layer, 50, 50b, 50c... cathode diffusion layer, 51, 51b, 51c... cathode gas flow channel forming portion, 52... first portion, 53... second portion, 60... anode diffusion layer, 70... cathode separator, 71... groove, 75... cathode gas flow channel, 80... anode separator, 81... groove, 85... anode gas flow channel, 100... fuel cell, 110... first roller, 111... groove, 120... second roller, 131... low compression portion, 132... high compression portion, C... intermediate position, S... reference surface

Claims

1. A fuel cell, a gas diffusion layer; a separator having a gas flow path for supplying gas to the gas diffusion layer, the separator facing the gas diffusion layer and being in contact with the gas diffusion layer; the gas diffusion layer includes a gas flow path forming portion that forms a part of the gas flow path along a flow path direction that is a direction in which the gas flows through the gas flow path, The gas flow path forming portion is A first part; and a second portion adjacent to the first portion in the flow path direction, a protruding amount of the first portion into the gas flow path is greater than a protruding amount of the second portion into the gas flow path; fuel cell.

2. 2. The fuel cell according to claim 1, a compressibility of the gas diffusion layer in the first portion is lower than a compressibility of the gas diffusion layer in the second portion; fuel cell.

3. 2. The fuel cell according to claim 1, an area of the first portion occupying the gas flow path forming portion upstream of an intermediate position in the flow path direction is larger than an area of the first portion occupying the gas flow path forming portion downstream of the intermediate position; fuel cell.

4. 2. The fuel cell according to claim 1, an area of the first portion occupying the gas flow path forming portion downstream of an intermediate position in the flow path direction is larger than an area of the first portion occupying the gas flow path forming portion upstream of the intermediate position; fuel cell.

5. 2. The fuel cell according to claim 1, the separator includes a plurality of the gas flow channels arranged in parallel to each other, the gas diffusion layer includes a plurality of the gas flow path forming portions arranged in parallel to each other, each of the gas flow path forming portions forms a part of a different gas flow path; the first portions of the gas flow path forming portions are arranged in a direction substantially perpendicular to the flow path direction within the surface of the gas diffusion layer; fuel cell.

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