Separator for fuel cell

Abstract

A separator for a fuel cell is provided with a plate-shaped main body having a plurality of ribs extending in parallel. The rib is in contact with the gas diffusion layer of the membrane electrode gas diffusion layer assembly by protruding from the main body. A space between the plurality of ribs and between the main body and the gas diffusion layer constitutes a flow path through which a gas supplied / discharged to / from the membrane electrode gas diffusion layer assembly flows. The rib is provided with a partition section that partitions a plurality of flow paths extending in parallel between the upstream and downstream in the flow direction of the gas in the flow paths. The positions of the partitions in the flow path in the direction of flow of the gas are set so as not to be at the same position in the flow paths adjacent to each other in the direction in which the parallel ribs are arranged.

Description

Technical Field

[0001] This disclosure relates to separators for fuel cells. Background Technology

[0002] The fuel cell stack is formed by stacking individual cells along the thickness direction. Each individual cell is formed by clamping the membrane electrode gas diffusion layer assembly from both sides in the thickness direction using plate-like spacers. As shown in Japanese Patent Application Publication No. 2010-3531, the fuel cell spacers have a main body with multiple ribs extending in a parallel manner. The ribs protrude from the main body and contact the gas diffusion layer of the membrane electrode gas diffusion layer assembly. Flow paths for supplying / exhausting gas relative to the membrane electrode gas diffusion layer assembly are formed in the spaces between the multiple ribs and between the gas diffusion layers.

[0003] Fuel gas, such as hydrogen, flows in the flow path between the separator on the anode side and the gas diffusion layer on the anode side, located on both sides of the membrane electrode gas diffusion layer junction in the thickness direction. Additionally, oxidizing gas, such as air, flows in the flow path between the separator on the cathode side and the gas diffusion layer on the cathode side, located on both sides of the membrane electrode gas diffusion layer junction in the thickness direction. Furthermore, in a single cell, power generation is based on the reaction of the fuel gas and the oxidizing gas within the membrane electrode gas diffusion layer junction. The gas diffusion layer of the membrane electrode gas diffusion layer junction serves to diffuse the gas supplied to the membrane electrode gas diffusion layer junction from the aforementioned flow path, thereby ensuring a uniform gas supply relative to the membrane electrode gas diffusion layer junction. Summary of the Invention

[0004] The problem that the invention aims to solve

[0005] In the aforementioned single cell, the gas within the flow path flows along the ribs, making it difficult for it to enter the gas diffusion layer of the membrane electrode gas diffusion layer junction. As a result, the gas supplied from the flow path to the membrane electrode gas diffusion layer junction is difficult to diffuse in the gas diffusion layer, potentially reducing the power generation efficiency of the single cell.

[0006] Solution for solving the problem

[0007] One aspect of the present disclosure is a fuel cell separator comprising a plate-shaped body having a plurality of ribs extending in parallel. The body is configured to be disposed on either side of a membrane electrode gas diffusion layer assembly in the thickness direction. The ribs protrude from the body and contact the gas diffusion layer of the membrane electrode gas diffusion layer assembly. The space between the plurality of ribs and between the body and the gas diffusion layer forms a flow path for supplying / exhausting gas relative to the membrane electrode gas diffusion layer assembly. The ribs have partitions that separate the upstream and downstream of the gas flow path in the flow path. The partitions in the gas flow direction of the flow path are positioned such that adjacent flow paths in the parallel direction of the parallel ribs are not located at the same position. Attached Figure Description

[0008] Figure 1 This is an exploded 3D view representing a single cell of a fuel cell.

[0009] Figure 2 It means to Figure 1 A cross-sectional view of a battery stack composed of stacked individual cells.

[0010] Figure 3 It means Figure 1 A schematic diagram of the separator ribs and flow path in a single cell.

[0011] Figure 4 It indicates that they are stacked. Figure 1 A schematic diagram of the contact points between adjacent single cells when using a single cell.

[0012] Figure 5 This is a schematic diagram showing the ribs of the separator and other examples of flow paths in a single cell.

[0013] Figure 6 This is a schematic diagram showing the ribs of the separator and other examples of flow paths in a single cell.

[0014] Figure 7 This is a schematic diagram showing the ribs of the separator and other examples of flow paths in a single cell.

[0015] Figure 8 This is a schematic diagram showing the ribs of the separator and other examples of flow paths in a single cell.

[0016] Figure 9 This is a schematic diagram showing the ribs of the separator and other examples of flow paths in a single cell. Detailed Implementation

[0017] The following is for reference Figures 1-4 One embodiment of the separator for a fuel cell will be described.

[0018] Figure 1 A single cell 11 for forming a fuel cell stack is shown. The single cell 11 includes a resin plate 12, a membrane electrode gas diffusion layer (MED) assembly 13, and spacers 14. The resin plate 12 is formed in a rectangular frame shape. The outer edge of the MED assembly 13 is joined to the resin plate 12. Furthermore, the resin plate 12 and the MED assembly 13 are held together by spacers 14 disposed on both sides of them in the thickness direction.

[0019] The fuel cell stack is formed by overlapping the aforementioned single cells 11 along the thickness direction. Multiple holes 16 are formed in the resin plate 12 and the separator 14 of the single cell 11. Three of the multiple holes 16 are located at one end along the long side of the single cell 11, and the other three are located at the other end along the long side of the single cell 11. The multiple holes 16 are grouped in pairs by one hole at one end and one hole at the other end along the long side of the single cell 11. Each group of holes 16 is used to supply fluids such as fuel gases like hydrogen, oxidizing gases like air, and refrigerants such as cooling water.

[0020] The separator 14 has a rectangular plate-shaped body 15 formed from a metal such as stainless steel, titanium, or aluminum. Multiple ribs 19 are formed on the body 15 in a parallel arrangement extending along its long side. A sealing member 17 is disposed between the body 15 of the separator 14 and the resin plate 12. The sealing member 17 can be disposed on both the front and back surfaces of the resin plate 12 in the thickness direction.

[0021] A sealing member 17 disposed on the surface side of the resin plate 12 surrounds the resin plate 12 and the two sets of holes 16 located on one of the two diagonals of the separator 14, as well as the anode side of the membrane electrode gas diffusion layer junction 13. The sealing member 17 also surrounds a plurality of ribs 19 in the separator 14 located on the anode side. Furthermore, a flow path 18 for supplying fuel gas is formed between the plurality of ribs 19 in the separator 14. The fuel gas can flow through the two sets of holes 16 in the flow path 18.

[0022] A sealing member 17 disposed on the back side of the resin plate 12 surrounds the resin plate 12 and the two sets of holes 16 located on the other diagonal of the two diagonals of the separator 14, as well as the cathode side of the membrane electrode gas diffusion layer junction 13. The sealing member 17 also surrounds a plurality of ribs 19 in the separator 14 located on the cathode side. Furthermore, a flow path 18 for supplying oxidizing gas is formed between the plurality of ribs 19 in the separator 14. The oxidizing gas can flow through the two sets of holes 16 in the flow path 18.

[0023] In the battery stack of the single cell 11, fuel gas flows to the anode side of the membrane electrode gas diffusion layer junction 13, and oxidizing gas flows to the cathode side of the membrane electrode gas diffusion layer junction 13. Thus, when the fuel gas and oxidizing gas flow into the anode and cathode sides of the membrane electrode gas diffusion layer junction 13 respectively, power generation is achieved based on the reaction of these fuel gases and oxidizing gases in the membrane electrode gas diffusion layer junction 13.

[0024] like Figure 2 As shown, the membrane electrode gas diffusion layer junction 13 of the single cell 11 includes an electrolyte layer 20, a cathode electrode layer 21, an anode electrode layer 22, and a gas diffusion layer 23. The electrolyte layer 20 is formed, for example, from a solid polymer film. The cathode electrode layer 21 and the electrolyte layer 20 are located on one side in the thickness direction (…). Figure 1 The upper side of the anode electrode layer 22 is joined to the other side of the electrolyte layer 20 in the thickness direction. Figure 1 The cathode electrode layer 21, located on the opposite side of the electrolyte layer 20, is covered by a gas diffusion layer 23. The anode electrode layer 22, located on the opposite side of the electrolyte layer 20, is covered by a gas diffusion layer 23 that is different from the aforementioned gas diffusion layer 23.

[0025] The spacers 14 are respectively disposed on both the cathode side and the anode side of the membrane electrode gas diffusion layer junction 13. Multiple ribs 19 in the spacers 14 are formed by bending the body 15 of the spacer 14 so that they protrude in the thickness direction of the spacer 14. The spacers 14 located on the cathode side of the membrane electrode gas diffusion layer junction 13 have the same shape as those located on the anode side. However, the spacers 14 on the cathode side are positioned such that their two sides in the thickness direction are reversed relative to the spacers 14 on the anode side.

[0026] Multiple ribs 19 in the cathode-side separator 14 protrude toward the cathode-side gas diffusion layer 23. These ribs 19 are in contact with the cathode-side gas diffusion layer 23. The space between the multiple ribs 19 in the separator 14 and between the body 15 of the separator 14 and the gas diffusion layer 23 constitutes a flow path 18 for the flow of oxidizing gas. Multiple ribs 19 in the anode-side separator 14 protrude toward the gas diffusion layer 23. These ribs 19 are in contact with the anode-side gas diffusion layer 23. The space between the multiple ribs 19 in the separator 14 and between the body 15 of the separator 14 and the gas diffusion layer 23 constitutes a flow path 18 for the flow of fuel gas.

[0027] <Details of rib 19 and flow path 18 in separator 14>

[0028] Figure 3 Briefly illustrating the rib 19 of the separator 14 and the flow path 18. According to... Figure 3It can be seen that rib 19 has a partition 24 that separates the upstream and downstream flow directions of the multiple parallel flow paths 18 in the flow path 18. Furthermore, in Figure 3 In the diagram, the left side represents the upstream of the gas flow, and the right side represents the downstream of the gas flow.

[0029] The direction of gas flow in flow path 18 is... Figure 3 The position of the partition 24 in the left-right direction is set in the parallel direction of the above-mentioned ribs 19, that is... Figure 3 The adjacent flow paths 18 in the vertical direction are not located at the same position. Specifically, the partitions 24 are formed at equal intervals in the extending direction of the ribs 19. Furthermore, the partitions 24 corresponding to the defined flow path 18 are located in the middle of the partitions 24 corresponding to other flow paths 18 adjacent to the defined flow path 18 in the parallel direction of the parallel ribs 19.

[0030] The ribs 19 and partition portions 24 of the main body 15 in the separator 14 are formed as follows: That is, the separators 14 disposed on both sides of the membrane electrode gas diffusion layer junction 13 in the thickness direction are formed such that the downstream end of the flow path 18 blocked by the partition portion 24 of one separator 14 is located at a position corresponding to the downstream end of the flow path 18 blocked by the partition portion 24 of the other separator 14. Figure 3 In the diagram, solid lines represent flow paths 18 that are blocked by partitions 24 of one partition member 14, and dashed lines represent flow paths 18 that are blocked by partitions 24 of the other partition member 14.

[0031] The ribs 19 of the main body 15 in the separator 14 are formed in different directions when the separator 14 is located on one side of the membrane electrode gas diffusion layer junction 13 in the thickness direction and when it is located on the other side.

[0032] That is, rib 19 is formed in a direction that intersects the extension direction of rib 19. Figure 3 The rib 19 is wavy with amplitude in the vertical direction. By forming the rib 19 into a wavy shape, the extension direction of the rib 19 becomes different when the separator 14 is located on one side of the membrane electrode gas diffusion layer junction 13 in the thickness direction and when it is located on the other side.

[0033] As a result, when the fuel cell stack is pressed along the stacking direction of the individual cells 11, the portions of the main body 15 of the separator 14 in adjacent individual cells 11 that correspond to the bottom 18a of the flow path 18 come into contact with each other. These contact portions become formed by… Figure 4 The area indicated by the diagonal lines is the part.

[0034] <Effects of the separator 14 in this embodiment of the fuel cell>

[0035] (1) The flow path 18 for supplying / discharging gas relative to the membrane electrode gas diffusion layer junction 13 is separated upstream and downstream of the gas flow direction by the partition portion 24 of the rib 19. Therefore, when the gas flowing downstream in the flow path 18 reaches the downstream end of the flow path 18, which is the part separated by the partition portion 24, it enters the gas diffusion layer 23 from the downstream end. Furthermore, the gas entering the gas diffusion layer 23 exits from the downstream end of the flow path 18 as follows: Figure 3 The gas expands radially as shown by the double-dotted lines and then enters the adjacent flow path 18. The flow of the gas in this gas diffusion layer 23 promotes gas diffusion within the gas diffusion layer 23. As a result, it is possible to suppress the situation where the gas supplied from the flow path 18 to the membrane electrode gas diffusion layer junction 13 does not easily diffuse within the gas diffusion layer 23. Therefore, it is possible to suppress the situation where the power generation efficiency of the single cell 11 decreases due to the difficulty of gas diffusion within the gas diffusion layer 23.

[0036] However, assuming that the positions of the partitions 24 in the gas flow direction of the aforementioned flow path 18 are at the same locations in adjacent flow paths 18, the gases entering the gas diffusion layer 23 from the downstream ends of adjacent flow paths 18 may interfere with each other as they radially expand from the downstream ends. Furthermore, this gas interference makes it difficult for the gases to diffuse within the gas diffusion layer 23. However, if the positions of the partitions 24 in the gas flow direction of the aforementioned flow path 18 are not at the same locations in adjacent flow paths 18, then the situation where gases entering the gas diffusion layer 23 from the downstream ends of adjacent flow paths 18 interfere with each other as they radially expand from the downstream ends can be suppressed. As a result, the situation where gas interference makes it difficult for the gases to diffuse within the gas diffusion layer 23 can be suppressed.

[0037] (2) Separators 14 (body 15) are disposed on both sides of the membrane electrode gas diffusion layer assembly 13 in the thickness direction. Regarding the separators 14 located on both sides of the membrane electrode gas diffusion layer assembly 13 in the thickness direction, one of the separators 14 is flipped relative to the other separator 14. The ribs 19 and partitions 24 in the body 15 of the separator 14 are formed such that the downstream end of the flow path 18 blocked by the partition 24 in the body 15 of one separator 14 is located at a position corresponding to the downstream end of the flow path 18 blocked by the partition 24 in the body 15 of the other separator 14. Specifically, the downstream end of the flow path 18 on the side of one separator 14 is located at... Figure 3 The position shown by the solid line, and the downstream end of the flow path 18 on the other side of the separator 14 is located at... Figure 3The positions are indicated by the dashed lines. Therefore, the gas entering the gas diffusion layer 23 from the downstream end of the flow path 18 corresponding to one of the separators 14 and the gas entering the gas diffusion layer 23 from the downstream end of the flow path 18 corresponding to the other separator 14 are located at corresponding positions on both sides of the membrane electrode gas diffusion layer junction 13. As a result, the power generation efficiency is improved when power is generated based on the reaction of fuel gas and oxidizing gas in the membrane electrode gas diffusion layer junction 13.

[0038] (3) The ribs 19 of the main body 15 in the separator 14 are formed with different extension directions when the separator 14 is located on one side of the membrane electrode gas diffusion layer junction 13 in the thickness direction and when it is located on the other side. As a result, the portion of the main body 15 of the separator 14 corresponding to the bottom 18a of the flow path 18 also extends correspondingly to the ribs 19 of the main body 15. Furthermore, when the fuel cell stack is pressed along the stacking direction of the single cell 11, the portions of the main body 15 of the separator 14 corresponding to the bottom 18a of the flow path 18 in adjacent single cells 11 will come into contact with each other. In other words, the above portions will not be in a state of mutual misalignment. Therefore, it is possible to suppress the situation where, with the above portions being in a state of mutual misalignment, the surface pressure acting from the main body 15 of the separator 14 to the membrane electrode gas diffusion layer junction 13 decreases when the fuel cell stack is pressed along the stacking direction of the single cell 11, thereby leading to a deterioration in power generation efficiency.

[0039] (4) The ribs 19 of the main body 15 in the separator 14 are formed as waves with amplitude in a direction intersecting the extension direction of the ribs 19. As a result, the extension direction of the ribs 19 of the main body 15 in the separator 14 becomes different when the separator 14 is located on one side of the thickness direction of the membrane electrode gas diffusion layer junction 13 and when it is located on the other side.

[0040] (5) The partition portions 24 are formed at equal intervals in the extending direction of the ribs 19. Furthermore, the partition portions 24 corresponding to the defined flow path 18 are located in the middle of the partition portions 24 corresponding to other flow paths 18 adjacent to the aforementioned flow path 18 in the parallel direction of the parallel ribs 19. Therefore, it is possible to more effectively suppress the interference between gases entering the gas diffusion layer 23 from the downstream end of the adjacent flow path 18 when they expand radially from the aforementioned downstream end.

[0041] Furthermore, the above-described embodiments can be modified as follows. The above-described embodiments and the following modifications can be combined with each other to implement them without technical inconsistencies.

[0042] • The partition 24 corresponding to the specified flow path 18 is located in the middle of the partition 24 corresponding to other flow paths 18 adjacent to the above-mentioned flow path 18 in the parallel direction of the parallel ribs 19, but it is not necessary to set it in this way.

[0043] Rib 19 and flow path 18 may not necessarily be required. Figure 3 The curved shape shown can also be, for example, a shape that is curved like that. Figure 5 , Figure 6 or Figure 7 The shape is curved as shown.

[0044] Some of the ribs 19 and flow paths 18 can also be configured such that, for example, flow path 18 is as follows: Figure 8 and Figure 9 It becomes a straight line as shown.

[0045] Rib 19 does not necessarily need to be formed so that the extension direction is different when the separator 14 is located on one side of the membrane electrode gas diffusion layer junction 13 in the thickness direction and when it is located on the other side.

[0046] • The downstream end of the flow path 18 on one side of the separator 14 located on the thickness direction of the membrane electrode gas diffusion layer junction 13, formed based on the partition portion 24, does not necessarily need to be located in the same position as the downstream end of the flow path 18 on the other side of the separator 14.

Claims

1. A separator for a fuel cell, the separator having a plate-shaped body having a plurality of ribs extending in parallel. The main body is configured to be disposed on any one of the two sides in the thickness direction of the membrane electrode gas diffusion layer junction. The rib protrudes from the body and contacts the gas diffusion layer of the membrane electrode gas diffusion layer assembly. The spaces between the plurality of ribs and between the main body and the gas diffusion layer constitute a flow path for supplying / exiting gas relative to the membrane electrode gas diffusion layer junction, wherein, The rib has a partition that separates the upstream and downstream of the gas flow direction of the plurality of parallel flow paths. The position of the partition in the gas flow direction of the flow path is set such that adjacent flow paths in the parallel direction of the parallel ribs are not located at the same position.

2. The separator for the fuel cell according to claim 1, wherein, The separator is configured such that, when the separator is disposed on both sides in the thickness direction of the membrane electrode gas diffusion layer assembly, the main body of one of the separators is in a state where its surface is flipped relative to the main body of the other separator. The ribs and partitions of the main body are formed such that the downstream end of the flow path blocked by the partition in the main body of one of the partitions is located at a position corresponding to the downstream end of the flow path blocked by the partition in the main body of the other partition.

3. The separator for a fuel cell according to claim 1 or 2, wherein, The separator is configured such that, when the separator is disposed on both sides in the thickness direction of the membrane electrode gas diffusion layer assembly, the main body of one of the separators is in a state where its surface is flipped relative to the main body of the other separator. The ribs of the main body are formed such that when the main body is located on one side of the thickness direction of the membrane electrode gas diffusion layer junction and when it is located on the other side, the extension direction of the ribs is different.

4. The separator for a fuel cell according to claim 3, wherein, The rib is formed as a wave shape with amplitude in a direction intersecting the extension direction of the rib.

5. The separator of the fuel cell according to claim 1 or 2, wherein, The partition portions are formed at equal intervals in the extending direction of the ribs. The partition corresponding to the specified flow path is located in the middle of the partition corresponding to other flow paths adjacent to the flow path in the parallel direction of the parallel ribs.

Images