Gasdiffusionselement

Abstract

The design includes a rollable gas diffusion element. This element, made of a flexible material and positioned between a separator and a catalyst layer of a fuel cell system, comprises: a gas diffusion section with a plurality of first grooves oriented in a first direction and first ribs formed between adjacent first grooves, serving as gas flow paths on a surface on one side of the separator; a distributor that supplies gas to be introduced into the gas diffusion section; and an inlet section connecting the gas diffusion section.The introductory section features a multitude of second grooves, each with a second direction that differs from the first direction of the first groove, second ribs formed between adjacent second grooves, and third grooves, each with the same direction as the first direction.

Description

Technical field

[0001] The present invention relates to a gas diffusion element. State of the art

[0002] In a gas supply diffusion layer for a fuel cell system capable of gas permeation and diffusion, a configuration has been proposed in the prior art in which a gas flow path groove, which is directed from a gas inlet side to a gas outlet side, is provided on a surface of a porous body layer on a separator side (for example, patent literature 1 and patent literature 2). List of citations from patent literature Patent Literature 1: JPWO2019 / 207811A Patent Literature 2: JPWO2019 / 239605A Summary of the invention: Technical problem

[0003] In general, a prior art gas supply diffusion layer for a fuel cell system consists of a carbon fiber composite material in the form of a nonwoven fabric and is sold as a roll-shaped product. However, a gas diffusion layer incorporating the gas flow path groove described above, including the prior art design, is difficult to roll in a specific direction depending on the groove's orientation. In particular, if multiple gas flow path grooves are formed in different directions, it becomes challenging to sell the product as a roll-shaped product. Furthermore, cutting such a gas diffusion layer to a predetermined size to create a layered product for each layer introduces problems such as increased costs.

[0004] The present invention has been made with regard to the aforementioned problem, and it is an object of the present invention to provide a gas diffusion element that can be marketed as a roll-shaped product even when flow path grooves are formed in several directions. Solution to the problem

[0005] To solve the aforementioned problems, according to one aspect of the present invention, a gas diffusion element is provided, which is made of a flexible material and is arranged between a separator and a catalyst layer of a fuel cell system. The gas diffusion element comprises: a gas diffusion section having a plurality of first grooves formed in a first direction and first ribs formed between adjacent first grooves, the plurality of first grooves serving as gas flow paths on a surface on one side of the separator; and an inlet section connecting a distributor, which supplies a gas to be introduced into the gas diffusion section, to the gas diffusion section.The introductory section features a multitude of second grooves, each with a second direction that differs from the first direction of the first groove, second ribs formed between adjacent second grooves, and third grooves, each with the same direction as the first direction. Advantageous effects of the invention

[0006] According to the present invention, for example, even if flow path grooves are formed in several directions in each area, it is possible to provide a gas diffusion element that can be rolled and can contribute to efficiency in terms of productivity, storage, distribution and the like. Brief description of the drawings Fig. Figure 1 is a schematic view of a configuration example of a fuel cell vehicle with a fuel cell system according to an embodiment of the present invention; Fig. Figure 2 is a schematic view of a configuration example of the fuel cell system according to the embodiment of the present invention; Fig. Figure 3 is a schematic view of a structural example of a fuel cell that is part of a fuel cell system according to the embodiment of the present invention; Fig. Figure 4 shows a schematic view of a structural example of a gas diffusion element which has a slightly rollable property in an X-axis direction, according to the embodiment of the present invention; Fig. Figure 5 is a perspective view in a Y-axis direction of an A-A' cross-section in Fig. 4; Fig. Figure 6 is a perspective view in the Y-axis direction of a B-B' cross-section in Fig. 4; Fig. Figure 7 is a perspective view in the Y-axis direction of a C-C' cross-section in Fig. 4; Fig. Figure 8 is a schematic view of a structural example of a gas diffusion element that is easily rollable in the X-axis direction, according to a modification; Fig. Figure 9 is a schematic view of a structural example of a gas diffusion element according to a further modification; Fig. Figure 10 is a schematic view of a structural example of a gas diffusion element which has a slightly rollable property in the X-axis direction, according to a further modification; Fig. Figure 11 is a perspective view in the Y-axis direction of a D-D' cross-section in Fig. 10; Fig. Figure 12 is a schematic view of a structural example of a gas diffusion element that is easily rollable in the X-axis direction, according to a further modification; Fig. Figure 13 is a perspective view in the Y-axis direction of an E-E' cross-section in Fig. 1.1 Fig. Figure 14 is a schematic view of a structural example of a gas diffusion element that is easily rollable in the Y-axis direction, according to a further modification. Description of the embodiments

[0007] Preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. In the description and in the drawings, elements with essentially the same functions are designated by the same reference numerals, and a repeated description thereof is omitted. Furthermore, configurations other than those described in detail below can be realized, for example, by appropriately applying known techniques, including those described above in patent literature or by considering vehicle configurations. Fuel cell vehicle 200

[0008] Fig. Figure 1 is a schematic view of a configuration example of a fuel cell vehicle 200 with a fuel cell system 100 according to the present embodiment. The fuel cell vehicle 200 is configured as an all-wheel drive vehicle, which transmits drive torque output by a drive power source to the wheels to generate the vehicle's drive torque. In the present embodiment, the drive power source can be a known electric motor located on the front wheel side. In addition to the electric motor described above, the drive power source can also include an internal combustion engine such as a gasoline engine, a diesel engine, or a gas turbine engine.

[0009] An energy supply system that provides such a drive power source with the desired power comprises a fuel cell system 100, the detailed structure of which will be described later, a hydrogen gas supply unit with a known hydrogen tank 23 and a line, an air supply unit with a known compressor 31 and a line, a known secondary battery, such as a lithium-ion secondary battery or a lead-acid storage battery, a known inverter, and a control unit CU that controls these components. In this energy supply system, both the fuel cell system 100 and the secondary battery can supply energy to a load, including the electric motor described above.

[0010] Furthermore, in a hydrogen gas supply unit for supplying a fuel gas (hydrogen) to the fuel cell system 100, the hydrogen stored in the hydrogen tank 23 is supplied to an anode-side flow path of the fuel cell system 100 described above via a hydrogen inlet valve 32a or the like, which has a known structure and is installed in a hydrogen supply flow path.

[0011] A portion of the hydrogen gas emitted by the fuel cell system 100 can be recirculated into the hydrogen supply flow path via a recirculation path and a known recirculation pump. The remainder of the hydrogen gas emitted by the fuel cell system 100 is diluted at a predetermined time by a diluter 35 via an opening and closing process of a known hydrogen discharge valve 32b under the control of the control unit CU and then released (expelled) into the atmosphere.

[0012] On the other hand, an air supply unit for supplying oxygen gas (air) to the fuel cell system 100, in addition to the compressor 31 described above, has a known air supply valve 32c and an air discharge valve (backpressure valve) 32d, which regulate the amount of oxygen (air) supplied to the fuel cell system 100. The air supply unit can further include a known flow sensor (not shown) that is capable of measuring the flow rate of the air supplied to the fuel cell system 100.

[0013] The air drawn in by the compressor 31 is fed via the air supply valve 32c and a known humidifier (not shown) to a cathode-side flow path in the fuel cell system 100. Under the control of an oxygen discharge valve (backpressure valve) 32d, the air supplied to the fuel cell system 100 is fed by the control unit CU as cathode exhaust gas to the diluent 35.

[0014] The control unit (CU) comprises one or more processors (central processing units (CPUs)) and one or more memory modules, which are connected to the processor(s) in a communication-enabled manner. The control unit (CU) can be configured to connect to a known external network, such as the internet, via various common communication devices, for example, using a smartphone.

[0015] The compressor 31, valves 32 (the hydrogen inlet valve 32a, the hydrogen outlet valve 32b, the air supply valve 32c and the oxygen outlet valve 32d), known vehicle-internal sensors (not shown), such as a temperature sensor and a speed sensor, and the like are electrically connected directly or via a communication unit, such as a Controller Area Network (CAN) or a Local Inter Net (LIN), to such a control unit CU. Fuel cell system 100, fuel cell 70

[0016] Next, the fuel cell system 100, in which fuel cells 70 are stacked according to the present embodiment, will be described with reference to the Fig. 2 and Fig. 3 described. The fuel cell system 100 has a stacked structure in which a plurality of fuel cells 70, each with an electromotive force of about 1 V, are connected in series and stacked. For example, the fuel cell system 100 according to the present embodiment can be illustrated as a polymer electrolyte fuel cell (PEFC) system having a structure in which the fuel cells 70 are connected in series in a pair of known end plates 60 (a first end plate 60A and a second end plate 60B), which pressurize and hold the fuel cell system at both ends, so that a system voltage required by the fuel cell vehicle 200 is obtained.

[0017] In the fuel cell 70, a membrane electrode assembly 90 is arranged between a pair of known separators 80 (an air electrode-side separator 80A and a fuel electrode-side separator 80B), which are arranged on the fuel electrode side and the air electrode side, respectively. The membrane electrode assembly 90 comprises at least one cathode catalyst layer 20, a known anode catalyst layer 30 arranged opposite the cathode catalyst layer 20, and a known polymer electrolyte membrane 10 arranged between the cathode catalyst layer 20 and the anode catalyst layer 30. The membrane electrode assembly 90 further comprises an air electrode-side gas diffusion layer (first GDL) 40 and a fuel electrode-side gas diffusion layer (second GDL) 50.The air electrode side gas diffusion layer (first GDL) 40 is arranged between the air electrode side separator 80A and the cathode catalyst layer 20, and the fuel electrode side gas diffusion layer (second GDL) 50 is arranged between the fuel electrode side separator 80B and the anode catalyst layer 30. First embodiment

[0018] Below, a gas diffusion element for a fuel cell system of the present invention is described using the air electrode-side gas diffusion layer (first GDL) 40 with reference to the Fig. 4 and Fig. 6 is described as an example. The gas diffusion element for a fuel cell system of the present invention is not limited to the foregoing. That is to say, the gas diffusion element for a fuel cell system in the present invention can also be applied to the fuel electrode-side gas diffusion layer (second GDL) 50, which is arranged on an anode gas side of the fuel cell system.

[0019] The air electrode-side gas diffusion layer (first GDL) 40 is made of a material that is both conductive and gas-permeable. More precisely, the air electrode-side gas diffusion layer (first GDL) 40 is made of a porous and flexible base material, such as a carbon material. The air electrode-side gas diffusion layer (first GDL) 40 has a gas diffusion section 41, which forms a contact surface with the cathode catalyst layer 20 and through which air diffuses, and an inlet section 43, which connects the gas diffusion section 41 and a distributor MF for supplying gas to the gas diffusion section 41. The gas diffusion section 41 and the inlet section 43 can be integrally formed.

[0020] In general, in a fuel cell, a fuel gas or an oxidizer gas is introduced into a manifold on the gas inlet side, and the gas flows through a gas flow path and is discharged from a manifold on the outlet side. If a gas, for example air, is introduced into the manifold on the inlet side, the introduced air diffuses into the gas diffusion layer.

[0021] The air electrode-side gas diffusion layer (first GDL) 40 of the present invention is arranged between the air electrode-side separator 80A and the cathode catalyst layer 20 and has a gas flow path for gas diffusion on a surface on the side of the air electrode-side separator 80A. More precisely, the air electrode-side gas diffusion layer (first GDL) 40 has a plurality of first ribs 413 extending linearly in a Fig. The gas diffusion section 41 extends in the Y-direction shown in Figure 4. The air electrode-side gas diffusion layer (first GDL) 40 further comprises a plurality of first grooves 411 formed between the adjacent first ribs 413 and extending linearly in the Y-direction. A gas flow path GF1 is formed by the two adjacent first ribs 413 and the first groove 411 formed between the two adjacent first ribs 413. The gas flow path GF1 serves to diffuse the air supplied by the distributor MF into the gas diffusion section 41.

[0022] As in Fig. As shown in Figure 5, the heights (Ha) of the plurality of first ribs 413 can be equal. Furthermore, the depth of the first groove 411 corresponds to the height (Ha) of the first rib 413. The plurality of first ribs 413 and the plurality of first grooves 411, which are arranged between the plurality of first ribs 413, are arranged alternately at equal intervals in an X-direction of the gas diffusion section 41. Hereinafter, the Y-direction is defined as a direction in which the first groove 411 extends linearly, the X-direction is defined as a direction orthogonal to the Y-direction, and a Z-direction is defined as a thickness direction of the air electrode-side gas diffusion layer (first GDL) 40.

[0023] As in Fig. As shown in Figure 5, the width of the first rib 413 and the width of the first groove 411 in the X-direction are essentially the same, but the present invention is not limited to this, and those skilled in the art can suitably determine an optimal width. In particular, if the width of the first rib 413 is greater than that of the first groove 411, the strength of the entire gas diffusion section 41 can be improved. Furthermore, if the width of the first groove 411 is greater than that of the first rib 413, the pressure drop during gas diffusion can be reduced and the energy generation efficiency of the fuel cell system improved.

[0024] As in Fig. As shown in Figure 4, the first rib 413 and the first groove 411 extend along the Y-direction without changing their width; however, the present invention is not limited to this. In particular, by increasing the width of the first groove 411 with increasing distance from the inlet section 43, the pressure loss during gas diffusion can be reduced and the energy generation efficiency of the fuel cell system can be improved.

[0025] A top surface of the first rib 413 and a bottom surface of the first groove 411 may or may not be flat parallel to the air electrode-side separator 80A.

[0026] The air electrode-side gas diffusion layer (first GDL) 40 of the present invention, for example, has the following effects by providing the gas flow path GF1. Since the air electrode-side gas diffusion layer (first GDL) 40 has unevenness on the surface on the side of the air electrode-side separator 80A due to the first rib 413 and the first groove 411, the effect of gas diffusion can be improved by increasing the surface area. Furthermore, since it is not necessary to provide a gas flow path on the surface on the side of the air electrode-side separator 80A, the processing costs of the separator can be reduced.

[0027] Furthermore, the air electrode-side gas diffusion layer (first GDL) 40 has the inlet section 43 between the gas diffusion section 41 and the distributor MF. The inlet section 43 has the function of introducing the gas supplied by the distributor MF into the gas diffusion section 41. As in Fig. As shown in Figure 4, the inlet section 43 has grooves extending in two different directions. More precisely, the inlet section 43 has a plurality of third grooves 431 extending in the Y direction onto extension lines of the first grooves 411 of the gas diffusion section 41, and second grooves 433 extending in one direction (arrow direction P in Fig. 4) extend, intersecting the Y-direction in the same plane as the third grooves 431. Furthermore, the inlet section 43 can have a plurality of second ribs 435 between two adjacent second grooves 433. As in Fig. As shown in Figure 4, the second ribs 435 of the introductory section 43 are arranged in a dashed manner between the second grooves 433 and the third grooves 431, which extend in two different directions.

[0028] Fig. Figure 6 shows a B-B' cross-sectional view in Fig. 4, and Fig. Figure 7 shows a C-C' cross-sectional view. Fig. 6 and Fig. Figure 7 shows cross-sectional shapes of the second ribs 435 in the introductory section 43. As in the Fig. 6 and Fig. As shown in Figure 7, the second ribs 435, when different cross-sections are viewed in the Y-direction, are arranged such that they protrude at different positions in the X-direction. In a top view, as in Fig. As shown in Figure 4, the second ribs 435 are regularly distributed over at least a part of the surface of the inlet section 43 on the side of the air electrode-side separator 80A.

[0029] As in Fig. As shown in Figure 4, the width of the third groove 431 (w1) is essentially equal to the width of the first groove 411, but the present invention is not limited to this. That is, the width of the third groove 431 can be made narrower than the width of the first groove 411, and in this case the strength of the entire inlet section 43 can be improved.

[0030] A top surface of the second rib 435 in the inlet section 43 is in contact with and supports the surface on the side of the air electrode-side separator 80A. In this way, a gas flow path GF2 is formed in the inlet section 43 by the second groove 433, the third groove 431, and the second rib 435. The gas flow path GF2 communicates with the gas flow path GF1 in the gas diffusion section 41.

[0031] As in the Fig. 5, Fig. 6 to Fig. As shown in Figure 7, the heights (Ha) of the plurality of second ribs 435 can be equal to each other. The heights (Hb) of the second ribs 435 can correspond to the heights (Ha) of the first ribs 413. The depths of the second grooves 433 and the third grooves 431 correspond to the heights (Hb) of the second ribs 435.

[0032] As in Fig. As shown in Figure 4, the second grooves 433 extend linearly in a direction inclined at approximately 30° to 60° with respect to the Y-direction. A plurality of second grooves 433 are arranged parallel to one another in the introduction section 43. Since the plurality of second grooves 433 and the plurality of third grooves 431 intersect, the plurality of second ribs 435 in the introduction section 43 are arranged in an offset manner. One form of each second rib 435 is shown in Fig. Figure 4 is shown as a parallelogram, but the present invention is not limited to this. That is, the shape of each second rib 435 can be a rhombus or a circle. With regard to the arrangement and shape of the second ribs 435, it is preferred that the gas supplied from the distributor MF can be introduced into the gas diffusion section 41 and that a roller with the Y-direction of the air electrode-side gas diffusion layer (first GDL) 40 can be realized as an axis.

[0033] The air electrode-side gas diffusion layer (first GDL) 40 according to the present embodiment has, for example, the following effects by having the gas flow path GF2 in the inlet section 43. Since the third grooves 431 are formed on the extension lines of the first grooves 411, it is possible to roll the air electrode-side gas diffusion layer (first GDL) 40 with the Y-direction as its axis. That is, a groove or a rib of the inlet section 43 does not impede rolling with the Y-direction as its axis more than necessary.

[0034] In the present embodiment, the second grooves 433, which extend from the distributor MF towards the gas diffusion section 41, are formed in the inlet section 43. Therefore, the flow velocity distribution during gas introduction can be made uniform.

[0035] In the present embodiment, the inlet section 43 has the second ribs 435 between the adjacent second grooves 433. Therefore, the gas introduced into the inlet section 43 from the distributor MF flows between the second ribs 435 and is introduced into the gas diffusion section 41. A portion of the gas flowing between the second ribs 435 can branch into the third grooves 431. Modification 1

[0036] An air electrode-side gas diffusion layer (first GDL) 40a according to modification 1 is described with reference to Fig. 8 described. The air electrode-side gas diffusion layer (first GDL) 40a according to modification 1 has essentially the same configuration as a gas supply diffusion layer 40 of a fuel cell system according to the first embodiment, but differs from the first embodiment with respect to the shape of a second rib and the like. Therefore, mainly the differences are described, while similarities are indicated by the same reference numerals and their description is omitted.

[0037] One form of each of the second ribs 435a in modification 1 is in the direction P in Fig. 8 longer than that of each of the second ribs 435 in the first embodiment described above. Consequently, the number of second ribs 435a in the introductory section 43 is smaller than the number of second ribs 435 in the first embodiment. The number of third grooves 431a in modification 1 is smaller than the number of third grooves 431 in the first embodiment. In other words, in the present modification, the intervals between adjacent third grooves 431a are wider than the intervals between adjacent first grooves 411. With the configuration of modification 1, the area of ​​the second ribs 435a in the introductory section 43 is increased compared to the first embodiment, thus improving the strength of the introductory section 43.

[0038] In Fig. 8 the third groove 431a is formed linearly on the extension of the first groove 411, but the present invention is not limited to this. That is to say, as in Fig. As shown in Figure 9, the third grooves 431a can be discontinuous in the Y-direction. In this case, it can be said that the plurality of third grooves 431a formed on the adjacent second grooves 433 have an offset, as shown. Modification 2

[0039] An air electrode-side gas diffusion layer (first GDL) 40b according to a modification 2 is described with reference to the Fig. 10 and Fig. 11 described. Fig. Figure 10 is a schematic view of a structural example of a gas diffusion element which has a slightly rollable property in the X-axis direction, according to the present modification, and Fig. Figure 11 is a view for the schematic representation of a cross-section at position DD' of Fig. 10. The air electrode-side gas diffusion layer (first GDL) 40b according to modification 2 differs from that of the first embodiment with respect to the depth of a groove of the inlet section 43. Therefore, mainly these differences are described, and similarities are indicated by the same reference numerals and their description is omitted.

[0040] As in Fig. As shown in Figure 11, the depths (Hc) of the second groove 433b and the third groove 431b in modification 2 are deeper than the depths (Hb) of the second groove 433 and the third groove 431 according to the first embodiment. Therefore, compared to the first embodiment, this results in a reduction of the pressure loss when the gas is introduced into the inlet section 43. In the present modification, the width or depth of the second groove 433b may differ from the width or depth of the third groove 431b. For example, if the depth of the second groove 433b is deeper than that of the third groove 431b, it is possible to reduce the pressure loss when the gas flows in the P-direction. In the present modification, the width or depth of the third groove 431b may differ from the width or depth of the first groove 411.Furthermore, the width or depth of the second groove 433b can differ from the width or depth of the first groove 411. A wide width of the second groove 433b or the third groove 431b can contribute to a reduction in pressure loss. Similarly, a large depth of the second groove 433b or the third groove 431b can also contribute to a reduction in pressure loss. Modification 3

[0041] An air electrode-side gas diffusion layer (first GDL) 40c according to a modification 3 is described with reference to the Fig. 12 and Fig. 13 described. Fig. 12 is a top view according to modification 3, and Fig. Figure 13 is a perspective view in the Y-axis direction of an E-E' cross-section in Fig. 12. As in the Fig. 12 and Fig. As shown in Figure 13, modification 3 differs from the embodiments and modifications described above in the shape of the second rib 435c. More precisely, the second rib 435c according to modification 3 has the same length in the P-direction as that in modification 1 described above. On the other hand, with respect to the height of the second rib 435c, the highest section (Ha) is the same as that of the first rib 413, and recesses 436 are provided in a central area in the P-direction of each second rib 435c. As shown in Fig. As shown in Figure 11, the recesses 436 are provided on the extension lines of the first grooves 411 of the gas diffusion section 41. As shown in Fig. As shown in Figure 13, the height Hd of each depression 436 is less than the height (Ha) of the first rib 413.

[0042] As in modification 3, by providing the recesses 436 in the central region of the second ribs 435c, the recesses 436 support the rolling of the air electrode-side gas diffusion layer (first GDL) 40 with the Y-direction as its axis, and the rolling property can be further improved. Furthermore, the height of the second rib 435c can differ from the height of the first rib 413, and in this case, the rib height can be adjusted according to a difference in the surface pressure exerted on a rib between an introduction section and a power generation section. Modification 4

[0043] An air electrode-side gas diffusion layer (first GDL) 40d according to a modification 4 is described with reference to Fig. 14 described. Fig. Figure 14 is a top view according to modification 4. As in Fig.As shown in Figure 14, modification 4 differs from the embodiments and modifications described above with regard to the arrangement of the second grooves 433d, the third grooves 431d and the second ribs 435d.

[0044] More precisely, in modification 4, a plurality of first grooves 411d extending linearly in the X-direction and a plurality of first ribs 413d arranged between two adjacent first grooves 411d are provided in the gas diffusion section 41. Furthermore, the gas diffusion section 41 has a plurality of fourth grooves 415d extending linearly in the Y-direction. In the gas diffusion section 41, each first groove 411d and each fourth groove 415d intersect at right angles.

[0045] On the other hand, in the introductory section 43, the third grooves 431d extend linearly in the X-direction, and the second ribs 435d are arranged between two adjacent third grooves 431d. The second grooves 433d each extend in a direction that differs from the X-direction and the Y-direction in an XY plane.

[0046] The air electrode-side gas diffusion layer (first GDL) 40d according to modification 4 has the following effects due to the configuration described above. When a roller with the X-direction as its axis is used, the grooves and ribs do not interfere with the roller, thus improving its rolling characteristics. Since the second groove 433d and the fourth groove 415d are located in the introduction section 43 and the gas diffusion section 41, respectively, it is possible to implement the roller with the Y-axis direction as its axis. That is, the air electrode-side gas diffusion layer (first GDL) 40d according to modification 4 can support both a roller with the X-direction as its axis and a roller with the Y-direction as its axis.

[0047] Although the preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the technology of the present disclosure is not limited thereto. It is obvious to those skilled in the art that various modifications and changes are conceivable within the scope of the technical idea described in the claims, and it is understood that such modifications and changes fall within the technical scope of the present invention. List of reference symbols 100 fuel cell systems 200 fuel cell vehicles 10 Polymer electrolyte membrane 20 Cathode catalyst layer 30 anode catalyst layer 40 Air electrode-side gas diffusion layer (first GDL) 41 Gas diffusion section 411 first groove 413 first rib 43 Introductory section 431 third groove 433 second groove 435 second rib 50 Fuel electrode-side gas diffusion layer (second GDL) 60 End plate 70 Fuel cell 80 Separator 90 Membrane electrode arrangement

Claims

Gas diffusion element made of a flexible material and arranged between a separator and a catalyst layer of a fuel cell system, wherein the gas diffusion element comprises: a gas diffusion section with a plurality of first grooves formed in a first direction and first ribs formed between the adjacent first grooves, the first grooves serving as gas flow paths on a surface on one side of the separator;and an inlet section configured to supply a distributor configured to supply a gas to be introduced into the gas diffusion section, and to connect the gas diffusion section, wherein the inlet section has a plurality of second grooves, each having a second direction different from the first direction, second ribs formed between adjacent second grooves, and third grooves, each having the same direction as the first direction. Gas diffusion element according to claim 1, wherein the groove depth of the second groove and the groove depth of the first groove are different from each other. Gas diffusion element according to claim 1 or 2, wherein at least a part of the height of each of the second ribs differs from the height of each of the first ribs. Gas diffusion element according to claim 1 or 2, wherein a width or a depth of the third groove differs from a width or a depth of the first groove or the second groove. Gas diffusion element according to claim 1 or 2, wherein intervals between the adjacent third grooves and intervals between the adjacent first grooves are different from each other. Gas diffusion element according to claim 1 or 2, wherein the third grooves are discontinuous and two or more of the third grooves formed on the adjacent second grooves each have an offset.

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