Fuel Cells

Abstract

To provide a fuel battery that can achieve both the supply of reaction gas and the drainage of generated water.SOLUTION: A fuel battery 1 includes a membrane electrode assembly 11 in which an anode electrode 18, a solid polymer membrane 17, and a cathode electrode 19 are integrated, a pair of gas diffusion layers 13 that sandwich the membrane electrode assembly 11, and a pair of separators 16 that sandwich the membrane electrode assembly 11 from the front and back via the pair of gas diffusion layers 13. The separator 16 has a flat surface facing the gas diffusion layer 13. The gas diffusion layer 13 has a plurality of air flow paths 23 for circulating the gas supplied to the cathode electrode 19. The air flow path 23 includes an upstream passage 25 extending from an opening 23i located at one edge of the gas diffusion layer 13 and being interrupted inside the gas diffusion layer 13, and a downstream passage 26 extending from the inside of the gas diffusion layer 13 and reaching an opening 23o located at the other edge of the gas diffusion layer 13.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a fuel cell. [Background technology]

[0002] A conventional gas diffusion layer electrode substrate has a plurality of through holes extending from one surface to the other surface, and at least one of the density and diameter of the through holes varies in the planar direction.

[0003] There is known a fuel cell equipped with a bypass control valve that controls the amount of air discharged from a turbo compressor that is supplied to a fuel cell stack and the amount of air exhausted via a bypass pipe that bypasses the fuel cell stack. This fuel cell controls the opening of the bypass control valve so that the operating point of the turbo compressor falls within a non-surge region (for example, see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2005-038738 A Summary of the Invention [Problem to be solved by the invention]

[0005] Conventional gas diffusion layer electrode substrates have through holes, which reduces the flow resistance of the reactant gas, making it necessary to increase the flow rate of the reactant gas to expedite the drainage of generated water that accumulates in the gas diffusion layer.

[0006] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide a fuel cell capable of satisfying both the requirements for supplying reactant gases and discharging generated water. [Means for solving the problem]

[0007] In order to solve the above problems, the fuel cell according to the present invention includes a membrane electrode assembly in which an anode electrode, a solid polymer membrane, and a cathode electrode are integrated, a pair of gas diffusion layers sandwiching the membrane electrode assembly, and a pair of separators sandwiching the membrane electrode assembly from the front and back via the pair of gas diffusion layers. Each of the separators has a flat surface facing the corresponding gas diffusion layer, and each of the gas diffusion layers is porous and has a plurality of gas passages through which gas supplied to the anode electrode or the cathode electrode flows, and the plurality of gas passages are disposed on one edge of the gas diffusion layer. first Extending from the opening The downstream end An upstream passage that is interrupted inside the gas diffusion layer and an upstream passage that is disposed on the other edge of the gas diffusion layer second opening and the upstream end is terminated inside the gas diffusion layer. and a downstream passage. The downstream end of the upstream passage and the upstream end of the downstream passage are separated from each other via a part of the gas diffusion layer. Effect of the Invention

[0008] According to the present invention, it is possible to provide a fuel cell that is capable of satisfying both the supply of reactant gases and the drainage of generated water. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic perspective view of a fuel cell according to an embodiment of the present invention; [Diagram 2] 1 is an exploded perspective view of a fuel cell according to an embodiment of the present invention; [Diagram 3] FIG. 2 is a schematic diagram of a gas diffusion layer viewed from the separator side of the fuel cell according to the embodiment of the present invention. [Figure 4] 1 is a partial cross-sectional view intersecting the flow direction of a reactant gas flowing in a fuel cell according to an embodiment of the present invention; [Diagram 5] 1 is a partial cross-sectional view taken along a flow direction of a reactant gas flowing through a fuel cell according to an embodiment of the present invention; [Figure 6] FIG. 4 is a schematic diagram of a gas diffusion layer viewed from the separator side of a fuel cell according to a second example of an embodiment of the present invention. [Figure 7]FIG. 4 is a schematic diagram of a gas diffusion layer viewed from the separator side of a fuel cell according to a second example of an embodiment of the present invention. [Figure 8] FIG. 11 is a schematic diagram of a gas diffusion layer viewed from the separator side of a fuel cell according to a third example of an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] An embodiment of a fuel cell separator according to the present invention will be described with reference to Figures 1 to 8. In addition, the same reference numerals are used to denote the same or corresponding components in the various drawings.

[0011] FIG. 1 is a schematic perspective view of a fuel cell according to an embodiment of the present invention.

[0012] 1, a fuel cell 1 according to this embodiment generates power by reacting hydrogen gas as a fuel gas with oxygen (oxygen contained in air) as an oxidant gas. The fuel cell 1 includes a stack 5 having a plurality of stacked fuel cells 2, a pair of end plates 6 that sandwich the stack 5 from the outside in the stacking direction L of the plurality of fuel cells 2, and a plurality of fastening members 8 that span the pair of end plates 6 to integrate the stack 5 and the pair of end plates 6.

[0013] The fuel gas and the oxidant gas are collectively referred to simply as reactant gases.

[0014] The fuel cell 1 comprises a large number of stacked fuel cells 2. For this reason, the fuel cell 1 is also called a fuel cell stack. The fuel cell 1 has a fuel cell 2 as its smallest unit, and comprises tens to hundreds of stacked fuel cells 2. The number of stacked fuel cells 2 depends on the power generation capacity required of the fuel cell 1.

[0015] The pair of end plates 6 have a rectangular shape that is larger than the fuel cell 2. The pair of end plates 6 are connected by a fastening member 8 that spans between them.

[0016] The fastening members 8 apply a load inward in the stacking direction L to the multiple fuel cells 2 via the pair of end plates 6. This load acts in a direction that brings the pair of end plates 6 closer to each other, compressing the stack 5 in the stacking direction L.

[0017] FIG. 2 is an exploded perspective view of a fuel cell according to an embodiment of the present invention.

[0018] As shown in FIG. 2, a fuel cell 2 of a fuel cell 1 according to this embodiment includes a membrane electrode assembly 11 (MEA), a pair of gas diffusion layers 12, 13 (GDL) that sandwich the membrane electrode assembly 11, and a pair of separators 15, 16 that sandwich the membrane electrode assembly 11 from the front and back via the pair of gas diffusion layers 12, 13.

[0019] Furthermore, the fuel cell 2 has a coolant flow passage (not shown) between the separators 15, 16 adjacent to each other in the stacking direction, through which air serving as a coolant for cooling the fuel cell 1 flows.

[0020] FIG. 3 is a schematic diagram of a gas diffusion layer viewed from the separator side of a fuel cell according to an embodiment of the present invention.

[0021] FIG. 4 is a partial cross-sectional view intersecting the flow direction of the reactant gas flowing in the fuel cell according to the embodiment of the present invention.

[0022] FIG. 5 is a partial cross-sectional view taken along the flow direction of the reactant gas flowing through the fuel cell according to the embodiment of the present invention.

[0023] Fig. 3 is a schematic diagram of gas diffusion layer 13 as viewed from separator 16 side facing cathode 19 as an air electrode, and Fig. 4 is a partial cross-sectional view of separator 16 and gas diffusion layer 13 facing cathode 19. Gas diffusion layer 12 as viewed from separator 15 side facing anode 18 as a fuel electrode may also be configured similarly to Figs. 3 and 4.

[0024] 3 and 4 in addition to Fig. 2, the membrane electrode assembly 11 of the fuel cell 1 includes a solid polymer membrane 17 as an electrolyte, an anode 18, and a cathode 19. The membrane electrode assembly 11 is an integrated solid polymer membrane 17, anode 18, and cathode 19. The pair of electrodes 18, 19 sandwich the solid polymer membrane 17 from the front and back.

[0025] The pair of gas diffusion layers 12, 13 are porous membranes. The pair of gas diffusion layers 12, 13 supply hydrogen gas and air to the pair of electrodes 18, 19, collect electrons generated by chemical reactions, keep the solid polymer membrane 17 moist, and drain generated water.

[0026] A pair of subgaskets 21 are disposed around the pair of gas diffusion layers 12, 13. The pair of subgaskets 21 are thin films having a smaller gas permeability coefficient than the gas diffusion layers 12, 13, for example, made of polyethylene naphthalate (PEN) resin.

[0027] Each fuel cell 2 has a hydrogen gas flow path 22 (gas passage) that supplies hydrogen gas to the anode 18, and an air flow path 23 (gas passage) that supplies air to the cathode 19. The hydrogen gas flow path 22 is defined between the gas diffusion layer 12 facing the anode 18 and the separator 15. The air flow path 23 is defined between the gas diffusion layer 13 facing the cathode 19 and the separator 16.

[0028] 3, the gas diffusion layer 13 has a plurality of air flow paths 23 for circulating gas to be supplied to the cathode 19. The plurality of air flow paths 23 are groove-shaped and open to a surface 13a of the gas diffusion layer 13 facing the separator 16 and closed by the separator 16.

[0029] The air flow paths 23 include a plurality of upstream passages 31 extending from an opening 23i disposed on one edge of the gas diffusion layer 13 and terminated inside the gas diffusion layer 13, and a plurality of downstream passages 32 extending from the inside of the gas diffusion layer 13 and reaching an opening 23o disposed on the other edge of the gas diffusion layer 13. In other words, the upstream passages 31 and the downstream passages 32 are disconnected passages that are not continuously connected from one edge to the other edge of the gas diffusion layer 13, and do not penetrate between one edge and the other edge of the gas diffusion layer 13. In FIG. 3, the direction along the gas flow is indicated by a solid arrow X.

[0030] The upstream passages 31 and the downstream passages 32 extend in parallel without being connected to each other. The upstream passages 31 and the downstream passages 32 may be straight passages as shown in FIG. 3 or may be meandering passages.

[0031] Furthermore, the multiple upstream passages 31 and the multiple downstream passages 32 may be arranged in a staggered manner as shown in FIG. 3, or may be arranged in a straight line.

[0032] 3, the upstream passages 31 and downstream passages 32 arranged alternately may or may not have an overlap OL in a direction intersecting the gas flow (the direction of the solid arrow Y in FIG. 2). Also, the upstream passages 31 and downstream passages 32 having an overlap OL in the direction intersecting the gas flow (the direction of the solid arrow Y in FIG. 3) may be mixed with the upstream passages 31 and downstream passages 32 having no overlap. The direction Y intersecting the gas flow is also the alignment direction of the upstream passages 31 and downstream passages 32.

[0033] The multiple upstream passages 31 and multiple downstream passages 32 arranged in this manner have a portion between the downstream end of each upstream passage 31 and the upstream end of each downstream passage 32, which is separated by the gas diffusion layer 13. This portion has a large number of pores (not shown) in the gas diffusion layer 13. In other words, the upstream passages 31 and the downstream passages 32 are connected via the large number of pores in the gas diffusion layer 13. This portion has an extremely high pressure loss compared to the upstream passages 31 and the downstream passages 32. Therefore, for convenience, this portion is referred to as a high pressure loss portion 33.

[0034] That is, the gas supplied to the cathode 19 flows from the upstream passages 31 into the high pressure loss section 33, and then flows out from the high pressure loss section 33 to the downstream passages 32. In the high pressure loss section 33, the flow velocity of the gas flowing in from the upstream passages 31 increases. The gas with the increased flow velocity easily drains the generated water accumulated in the pores of the high pressure loss section 33 into the downstream passages 32.

[0035] Adjacent upstream passages 31 are also connected via a large number of pores in the gas diffusion layer 13. Therefore, the gas supplied to the cathode 19 easily drains the generated water accumulated in the pores between adjacent upstream passages 31. The same applies to the downstream passages 32.

[0036] The air flow path 23 is connected to an air inlet 41 and an air outlet 42 provided in the separator 16 .

[0037] An air inlet side manifold 45 is provided between the air inlet 41 and the air flow path 23. The air inlet side manifold 45 guides the air flowing in from the air inlet 41 to the air flow path 23. The air inlet side manifold 45 branches the air flowing in from the air inlet 41 to each upstream side passage 31. An air outlet side manifold (not shown) is provided between the air outlet 42 and the air flow path 23. The air outlet side manifold guides the air flowing out from the air flow path 23 to the air flow path 23. The air outlet side manifold collects the air flowing out from the air flow path 23 from each downstream side passage 32 to the air outlet 42.

[0038] 5 is a cross-sectional view of the fuel cell 2 in the vicinity of the air inlet 41. The air outlet 42, the hydrogen gas inlet 31, and the hydrogen gas outlet 32 ​​also have the same structure. Therefore, a cross-sectional view of the fuel cell 2 in the vicinity of the air outlet 42, a cross-sectional view of the fuel cell 2 in the vicinity of the hydrogen gas inlet 31, and a cross-sectional view of the fuel cell 2 in the vicinity of the hydrogen gas outlet 32 ​​are omitted.

[0039] The gas diffusion layer 12 has a plurality of hydrogen gas flow paths 22 through which gas supplied to the anode 18 flows. By configuring the hydrogen gas flow paths 22 in the same manner as the air flow paths 23 in Fig. 3, the drainage of water generated by back diffusion from the cathode 19 can be improved, and the effective reaction area of ​​the anode 18 can be expected to be improved.

[0040] The hydrogen gas flow path 22 is connected to a hydrogen gas inlet and a hydrogen gas outlet 32 ​​provided in the separator 15 .

[0041] A hydrogen gas inlet side manifold 35 is provided between the hydrogen gas inlet 31 and the hydrogen gas flow path 22. The hydrogen gas inlet side manifold 35 guides hydrogen gas flowing from the hydrogen gas inlet 31 to the hydrogen gas flow path 22. The hydrogen gas inlet side manifold 35 branches the hydrogen gas flowing from the hydrogen gas inlet 31 to each upstream passage. A hydrogen gas outlet side manifold 36 is provided between the hydrogen gas outlet 32 ​​and the hydrogen gas flow path 22. The hydrogen gas outlet side manifold 36 guides hydrogen gas flowing out from the hydrogen gas flow path 22 to the hydrogen gas outlet 32. The hydrogen gas outlet side manifold 36 collects hydrogen gas flowing out from the hydrogen gas flow path 22 from each downstream passage to the hydrogen gas outlet 32.

[0042] The separators 15, 16 are made of, for example, carbon fiber reinforced plastic, conductive resin, or metal. Each separator 15, 16 has a flat surface 15a, 16a facing the corresponding gas diffusion layer 12, 13. These flat surfaces 15a, 16a close the groove-shaped gas passages of the corresponding gas diffusion layer 12, 13.

[0043] The separator 15 facing the gas diffusion layer 12 facing the anode electrode 18 has an air inlet 51 for supplying air to the separator 16 facing the gas diffusion layer 13 facing the cathode electrode 19, and an air outlet 52 for discharging air from the separator 15.

[0044] A hydrogen gas side seal 59 protruding toward the membrane electrode assembly 11 is provided on the surface 15 a of the separator 15 .

[0045] The separator 16 facing the gas diffusion layer 13 facing the cathode electrode 19 has a hydrogen gas inlet 61 for supplying hydrogen gas to the separator 15 facing the gas diffusion layer 12 facing the anode electrode 18, and a hydrogen gas outlet 62 for discharging hydrogen gas from the separator 15.

[0046] An air-side seal 69 that protrudes toward the membrane electrode assembly 11 is provided on the surface 16 a of the separator 16 .

[0047] Next, other examples of the fuel cell 1 according to this embodiment will be described. In the fuel cells 1A and 1B described in each example, the same components as those in the fuel cell 1 are denoted by the same reference numerals, and duplicated descriptions will be omitted.

[0048] 6 and 7 are schematic diagrams of a gas diffusion layer viewed from the separator side of a fuel cell according to a second example of an embodiment of the present invention.

[0049] As shown in FIGS. 6 and 7, a gas diffusion layer 13A of a fuel cell 1A according to a second example of this embodiment (hereinafter simply referred to as "fuel cell 1A") has a plurality of air flow paths 23A.

[0050] The plurality of air passages 23A include closed intermediate passages 71 at the edge of the gas diffusion layer 13 that extend away from the upstream passages 31 and the downstream passages 32 .

[0051] The intermediate passage 71 , like the upstream passage 31 and the downstream passage 32 , has a groove shape that opens to the surface 13 a of the gas diffusion layer 13 facing the separator 16 and is closed by the separator 16 .

[0052] The intermediate passages 71 do not reach any edge of the gas diffusion layer 13 and are not directly connected to the upstream passages 31 and the downstream passages 32 .

[0053] The intermediate passage 71 extends parallel to the multiple upstream passages 31 and the multiple downstream passages 32. The intermediate passage 71 may be a straight passage as shown in Figures 6 and 7, or may be a serpentine passage.

[0054] Furthermore, the intermediate passage 71 does not have to be on an extension line of the upstream passage 31 and the downstream passage 32 as shown in FIG. 6, but may be parallel to the upstream passage 31 and the downstream passage 32, or may be disposed on an extension line of either the upstream passage 31 or the downstream passage 32 as shown in FIG. 7, or may be aligned in a straight line on an extension line of the upstream passage 31 and the downstream passage 32.

[0055] Further, as shown in FIG. 6, the intermediate passage 71 may or may not overlap with both the upstream passage 31 and the downstream passage 32 in the direction intersecting the gas flow (the direction of the solid arrow Y in FIG. 6). As shown in FIG. 7, the intermediate passage 71 may or may not overlap with either the upstream passage 31 or the downstream passage 32 in the direction intersecting the gas flow (the direction of the solid arrow Y in FIG. 7). Further, the adjacent intermediate passages 71 may or may not overlap with each other in the direction intersecting the gas flow (the direction of the solid arrow Y in FIG. 7). Further, the intermediate passages 71, the upstream passages 31, and the downstream passages 32 that overlap with each other in the direction intersecting the gas flow (the direction of the solid arrow Y in FIG. 2) may be mixed with the intermediate passages 71, the upstream passages 31, and the downstream passages 32 that do not overlap with each other. The direction Y intersecting the gas flow is also the direction in which the intermediate passage 71, the upstream passage 31, and the downstream passage 32 are aligned.

[0056] The multiple upstream passages 31, multiple downstream passages 32, and multiple intermediate passages 71 arranged in this manner have high pressure loss sections 33 separated by gas diffusion layers 13 between the downstream ends of each upstream passage 31, the upstream ends of each downstream passage 32, the upstream ends of the intermediate passages 71, and the downstream ends of the intermediate passages 71.

[0057] That is, the gas supplied to the cathode 19 flows from the upstream passages 31 into the high pressure loss section 33, passes through the high pressure loss section 33 into the intermediate passages 71, and then passes through the high pressure loss section 33 to the downstream passages 32. In the high pressure loss section 33, the flow velocity of the gas flowing in from the upstream passages 31 and the flow velocity of the gas flowing in from the intermediate passages 71 increase. The gas with the increased flow velocity easily drains the produced water accumulated in the pores of the high pressure loss section 33 into the intermediate passages 71 and downstream passages 32.

[0058] Adjacent upstream passages 31 are also connected via a large number of pores in the gas diffusion layer 13. Therefore, the gas supplied to the cathode 19 easily drains the generated water accumulated in the pores between adjacent upstream passages 31. The same applies to the intermediate passages 71 and the downstream passages 32.

[0059] FIG. 8 is a schematic diagram of a gas diffusion layer viewed from the separator side of a fuel cell according to a third example of an embodiment of the present invention.

[0060] As shown in FIG. 8, a gas diffusion layer 13B of a fuel cell 1B according to a third example of this embodiment (hereinafter simply referred to as "fuel cell 1B") has a plurality of air flow paths 23B.

[0061] The multiple air flow paths 23B include intermediate passages 71 that extend away from the upstream passages 31 and the downstream passages 32 and are not open to the edge of the gas diffusion layer 13, and relay passages 75 that connect at least two of the intermediate passages 71.

[0062] The relay passage 75 has a groove shape that opens to the surface 13 a of the gas diffusion layer 13 facing the separator 16 and is closed by the separator 16 , like the intermediate passage 71 , the upstream passage 31 , and the downstream passage 32 .

[0063] The relay passage 75 extends in a direction intersecting the plurality of intermediate passages 71. The intermediate passages 71 may be straight passages as shown in Fig. 8, or may be meandering passages.

[0064] Moreover, the relay passages 75 are connected to midway portions (non-end portions) of the respective intermediate passages 71. The relay passages 75 may or may not be aligned in a straight line in a direction intersecting the gas flow (the direction of solid arrow Y in FIG. 6) as shown in Fig. 8. Furthermore, the relay passages 75 may be perpendicular to the extension direction of the intermediate passages 71 as shown in Fig. 8, or may be inclined.

[0065] 8, the relay passage 75 has a function of adjusting the pressure loss so as to obtain a suitable pressure loss when a large number of intermediate passages 71 are arranged between the upstream passage 31 and the downstream passage 32 and the pressure loss between the upstream passage 31 and the downstream passage 32 increases too much. Therefore, the relay passage 75 does not need to connect all the intermediate passages 71, and is adjusted in an appropriate number at appropriate locations.

[0066] As described above, the fuel cells 1, 1A, and 1B according to the present embodiment are provided with a plurality of air flow paths 23, including an upstream passage 31 extending from an opening 23i disposed on one edge of the gas diffusion layer 13 and interrupted inside the gas diffusion layer 13, and a downstream passage 32 extending from inside the gas diffusion layer 13 and reaching an opening 23o disposed on the other edge of the gas diffusion layer 13. The gas diffusion layer 13 is porous, and there is no passage that is continuously connected from the opening 23i as the inlet of the air flow path 23 to the opening 23o as the outlet of the air flow path 23, and air as a reactant gas can be circulated through interrupted passages such as the upstream passage 31 and the downstream passage 32. Therefore, the air flow path 23 includes a high pressure loss section 33. In this high pressure loss section 33, the produced water accumulated in the pores is easily drained to the downstream passage 32 by the air as a reactant gas flowing in from the upstream passage 31. Therefore, the fuel cell 1 can achieve both the supply of the reactant gas and the drainage of the produced water.

[0067] In addition, the upstream passage 31 and the downstream passage 32 of the fuel cells 1, 1A, and 1B according to this embodiment overlap in a direction intersecting the flow of the reactant gas. In this overlapping portion, the linear distance between the downstream end of the upstream passage 31 and the upstream end of the downstream passage 32 is the shortest, and the influence of the pressure loss in the high pressure loss section 33 is small. That is, in the overlapping portion, the reactant gas easily flows from the upstream passage 31 to the downstream passage 32. Therefore, in the overlapping portion, the deceleration caused by the reactant gas being diffused too much into the gas diffusion layer 13 is suppressed, and the generated water accumulated in the high pressure loss section 33 can be drained more efficiently. Therefore, the fuel cell 1 can achieve both the supply of the reactant gas and the drainage of the generated water.

[0068] Furthermore, the fuel cells 1, 1A, and 1B according to this embodiment are provided with air flow paths 23 having a groove shape that is open on the surface 13a of the gas diffusion layer 13 facing the separator 16 and is closed by the separator 16. Therefore, compared to conventional fuel cells that have air flow paths in the separator 16, which has inferior drainage properties compared to the gas diffusion layer 13, the fuel cell 1 can achieve both the supply of reactant gases and the drainage of generated water.

[0069] Moreover, the fuel cells 1A and 1B according to this embodiment have a closed intermediate passage 71 at the edge of the gas diffusion layer 13, which extends to a location away from the upstream passage 31 and the downstream passage 32. The intermediate passage 71 is separated from and not connected to either the upstream passage 31 or the downstream passage 32. The intermediate passage 71 diffuses the reactant gas over a wider range of the gas diffusion layer 13 and suppresses a decrease in the flow rate of the reactant gas, compared to a case where only the upstream passage 31 and the downstream passage 32 are provided. Therefore, the fuel cell 1 can achieve both the supply of the reactant gas and the drainage of the generated water.

[0070] Furthermore, the fuel cell 1B according to this embodiment has a relay passage 75 that connects at least two intermediate passages 71. Therefore, the fuel cell 1B can appropriately adjust the pressure loss throughout the intermediate passages 71, the upstream passage 31, and the downstream passage 32, and can achieve both good reactant gas supply and good drainage of generated water.

[0071] Furthermore, the relay passages 75 of the fuel cell 1B according to this embodiment are connected to non-ends of the respective intermediate passages 71. Therefore, the fuel cell 1B can efficiently diffuse the reactant gas over a wider range in the area where the intermediate passages 71, the upstream passages 31, and the downstream passages 32 are concentrated.

[0072] In addition, by configuring the hydrogen gas flow path 22 as in the air flow paths 23, 23A, and 23B of Figures 3 to 8, the drainage of water generated by back diffusion from the cathode electrode 19 can be improved, and the effective reaction area of ​​the anode electrode 18 can be expected to be improved.

[0073] Therefore, the fuel cells 1, 1A, and 1B according to the present invention can easily achieve both the supply of reactant gases and the drainage of generated water. [Explanation of symbols]

[0074] 1, 1A, 1B... fuel cell, 2... fuel cell cell, 5... laminate, 6... end plate, 8... fastening member, 11... membrane electrode assembly, 12, 13, 13A, 13B... gas diffusion layer, 13a... gas diffusion layer surface, 15, 16... separator, 15a, 16a... separator surface, 17... solid polymer membrane, 18... anode electrode, 19... cathode electrode, 21... subgasket, 22... hydrogen gas flow path, 23, 23A, 23B... air flow path, 23i... opening, 23o... Opening, 25...upstream passage, 26...downstream passage, 31...hydrogen gas inlet, 32...hydrogen gas outlet, 33...high pressure loss section, 35...hydrogen gas inlet side manifold, 36...hydrogen gas outlet side manifold, 41...air inlet, 42...air outlet, 45...air inlet side manifold, 51...air inlet, 52...air outlet, 59...hydrogen gas side seal, 61...hydrogen gas inlet, 62...hydrogen gas outlet, 69...air side seal, 71...intermediate passage, 75...relay passage.

Claims

1. a membrane electrode assembly in which an anode electrode, a solid polymer membrane, and a cathode electrode are integrated; A pair of gas diffusion layers sandwiching the membrane electrode assembly; a pair of separators sandwiching the membrane electrode assembly from the front and back via the pair of gas diffusion layers; Each of the separators has a flat surface facing the corresponding gas diffusion layer, Each of the gas diffusion layers is porous and has a plurality of gas passages through which gas supplied to the anode or the cathode flows; the plurality of gas passages include an upstream passage extending from a first opening disposed on one edge of the gas diffusion layer and having a downstream end terminated inside the gas diffusion layer, and a downstream passage extending from a second opening disposed on the other edge of the gas diffusion layer and having an upstream end terminated inside the gas diffusion layer, the downstream end of the upstream passage and the upstream end of the downstream passage are separated from each other via a part of the gas diffusion layer.

2. 2. The fuel cell according to claim 1, wherein the plurality of gas passages includes a non-open intermediate passage formed away from the downstream end of the upstream passage and / or the upstream end of the downstream passage via a portion of the gas diffusion layer.

3. 3. The fuel cell according to claim 2, wherein the plurality of gas passages includes a plurality of the intermediate passages and a relay passage connecting at least two of the intermediate passages.

4. The fuel cell according to claim 3 , wherein the relay passages are connected to non-ends of each of the relay passages.

5. 5. The fuel cell according to claim 1, wherein the downstream end of the upstream passage and the upstream end of the downstream passage are separated via a portion of the gas diffusion layer so as to overlap in a direction intersecting the gas flow.

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