JP7077933B2 - Fuel cell - Google Patents

Description

The present invention relates to a fuel cell.

A fuel cell is a system that obtains electrical energy by supplying a fuel gas and an oxidizing agent gas to an anode-side electrode and a cathode-side electrode and causing them to react electrochemically.

Generally, a fuel cell has a stack structure in which a plurality of fuel cell cells are stacked. This fuel cell is composed of a membrane electrode assembly in which an anode-side catalyst layer and a cathode-side catalyst layer are provided on both sides of an electrolyte membrane, and a pair of separators sandwiching the membrane electrode assembly. In the above fuel cell, for the purpose of further improving the gas diffusivity to the membrane electrode assembly, a gas diffusion layer which is a base material for a porous diffusion layer is arranged on both sides of the membrane electrode assembly to form a membrane electrode. A gas diffusion layer assembly may be formed, and the membrane electrode gas diffusion layer assembly may be sandwiched between a pair of separators. Here, in Patent Document 1, a gas flow path as a gas flow path forming body is formed on the side of the separator facing the membrane electrode gas diffusion layer junction, and the gas flow direction is in the gas flow path. It is disclosed that by providing a plurality of protrusions extending in orthogonal directions, the protrusions function as a throttle for the flow path, and the reaction gas can be uniformly diffused in the gas diffusion layer.

Japanese Unexamined Patent Publication No. 2017-228482

Here, in order to further improve the gas diffusibility to the gas diffusion layer, it is necessary to make it easier for the reaction gas staying upstream of the throttle portion to diffuse into the gas diffusion layer. Therefore, it is necessary to increase the porosity of the gas diffusion layer. However, when the porosity of the gas diffusion layer is large, the porous substrate becomes sparse, and the electron conductivity decreases. Therefore, there has been a demand for a technique that achieves both electron conductivity and gas diffusivity in the vicinity of the throttle portion.

In order to achieve at least a part of the above-mentioned problems, the present invention can be carried out as the following embodiments.

According to one embodiment of the present invention, a pair of gas diffusion layers, which are a porous base material for a diffusion layer, are arranged on both sides of the membrane electrode assembly and the membrane electrode assembly, and the pair of gas diffusion layers. A fuel cell including a pair of separators arranged on both sides, wherein a reaction gas supply manifold and a reaction gas discharge manifold penetrating in the thickness direction are arranged in the pair of separators. In at least one of the separators, a plurality of gas flow paths for allowing the reaction gas to flow from the reaction gas supply manifold toward the reaction gas discharge manifold are arranged, and the plurality of gas flow paths are adjacent to each other. A plurality of non-flow passage portions that come into contact with the gas diffusion layer are provided between the matching gas flow paths, and the non-flow passage portions are continuously provided along the plurality of gas flow paths. At least one non-flow passage portion among the plurality of non-flow passage portions has a throttle portion adjacent to a gas flow path having a first flow path cross-sectional area and a second flow path cross-sectional area. The first flow path cross-sectional area includes an upstream portion arranged adjacent to the gas flow path and adjacent to the upstream of the throttle portion, and a main portion arranged adjacent to the upstream of the upstream portion. Assuming that the distance between the main portion and the membrane electrode assembly is the first distance, which is smaller than the second flow path cross-sectional area, the distance between the throttle portion and the membrane electrode assembly is the first. It is formed so as to have a second distance shorter than the distance, and the distance between the upstream portion and the membrane electrode assembly is formed to be a third distance longer than the first distance.

According to this embodiment, the plurality of non-flow passage portions provided in the separator have three different heights from the first distance, the second distance, and the third distance, so that the gas diffuses in contact with the separator. The magnitude of the contact surface pressure acting on the layer is different. Therefore, the thickness of the gas diffusion layer in which a plurality of non-channel portions adjacent to each of the main portion, the throttle portion, and the upstream portion are in contact with each other is different. The gas diffusion layer is a base material for a porous diffusion layer. The higher the working contact surface pressure of the gas diffusion layer, the smaller the thickness of the gas diffusion layer. While the electron conductivity is improved, the void ratio of the gas diffusion layer becomes smaller and the gas diffusivity decreases. The second distance is higher than the first distance and the third distance, and the thickness of the gas diffusion layer is thin. Therefore, the contact surface pressure acting on the gas diffusion layer in the throttle portion adjacent to the upstream portion is high, and the thickness of the gas diffusion layer becomes thin, so that the void ratio of the gas diffusion layer becomes small and the electron conductivity becomes good. On the other hand, the contact surface pressure in the upstream portion is lower than that in the throttle portion and the main portion, and the thickness of the gas diffusion layer is increased. Therefore, in the upstream portion where the reaction gas flowing through the gas flow path tends to stay due to the throttle portion, the reaction gas is more likely to diffuse into the gas diffusion layer than in the throttle portion and the main portion. Since the portion where the contact surface pressure is high and the portion where the contact surface pressure is low are provided close to each other, the reaction gas diffuses into a part of the gas diffusion layer in contact with the upstream portion where the reaction gas easily diffuses. It can diffuse to a part of the gas diffusion layer that comes into contact with the difficult drawing portion. On the other hand, since the throttle portion having high electron conductivity is arranged adjacent to the upstream portion having low electron conductivity, the electron conductivity also becomes uniform in the vicinity of the throttle portion. Therefore, both electron conductivity and gas diffusivity can be achieved in the vicinity of the throttle portion.

In the fuel cell separator of the above embodiment, the non-flow path portion of at least one of the plurality of non-flow passage portions has the second distance and the third distance between the throttle portion and the upstream portion. It may have a surface parallel to the membrane electrode assembly and a surface not perpendicular to the membrane electrode assembly whose height changes continuously up to the second or third distance.

According to this form, since the height changes continuously, it is possible to suppress the generation of a gap between the gas diffusion layer and the separator. Therefore, the electron conductivity can be further improved.

In the fuel cell separator of the above embodiment, at least one non-flow path portion of the plurality of non-flow path portions is perpendicular to the membrane electrode assembly of the non-channel portion and with respect to the gas flow direction. The cross section in the parallel plane may be arcuate in the throttle portion and the upstream portion.

According to this form, since the throttle portion and the upstream portion have an arc shape, it is possible to suppress the generation of a gap between the gas diffusion layer and the separator. Therefore, the electron conductivity can be further improved.

It is sectional drawing explanatory drawing of the fuel cell which concerns on this embodiment. It is a top view which shows the schematic structure of the separator which concerns on this embodiment. It is sectional drawing of the fuel cell which concerns on this embodiment, and is the figure for demonstrating the flow of a gas. It is an enlarged plan view of the region C shown in FIG. 2 and the cross-sectional view taken along the line AA of FIG. 4 (a). It is an enlarged plan view of the region C shown in FIG. 2 in the modification, and is a sectional view taken along the line BB of FIG. 5 (a). It is a top view which shows the schematic structure of the separator which concerns on a modification.

Hereinafter, the fuel cell separator of the present invention will be described in detail with reference to the drawings. It should be noted that the following embodiments are merely suitable application examples, and the scope of application of the present invention is not limited thereto.

FIG. 1 is a cross-sectional view showing the configuration of a fuel cell 100 as an embodiment of the present invention. The fuel cell 100 includes a membrane electrode assembly 10, two gas diffusion layers 20, and a pair of separators, that is, an anode-side separator 30 and a cathode-side separator 40. In the membrane electrode assembly 10, an anode-side catalyst layer 11 and a cathode-side catalyst layer 12 are arranged on both sides of the electrolyte membrane 13, respectively. The electrolyte membrane 13 is a solid polymer membrane that exhibits good proton conductivity in a wet state. In the present embodiment, the electrolyte membrane 13 is composed of an ion exchange membrane of a fluororesin. The anode-side catalyst layer 11 and the cathode-side catalyst layer 12 are composed of a catalyst that promotes a chemical reaction between the fuel gas and the oxidant gas.

Gas diffusion layers 20 are laminated on both sides of the membrane electrode assembly 10. The membrane electrode assembly 10 and the two gas diffusion layers 20 constitute a membrane electrode gas diffusion layer assembly (hereinafter referred to as "MEGA") 21. The gas diffusion layer 20 is a layer that diffuses the reaction gas used for the electrode reaction along the plane direction of the electrolyte membrane 13, and is composed of a porous base material for a diffusion layer. As the base material for the diffusion layer, a porous base material having conductivity and gas diffusivity, such as a carbon fiber base material and a graphite fiber base material, is used. The membrane electrode assembly 10 side of the gas diffusion layer 20 is water-repellent.

An uneven surface is formed on the two separators 30 and 40, and the gas flow paths 32 and 42 are formed by bringing the upper surfaces 36 and 46 of the convex portion of the uneven surface into contact with the gas diffusion layer 20. Since the reaction gas flows through the concave portions of the uneven surface and the reaction gas hardly flows through the upper surfaces 36 and 46 of the convex portions in contact with the gas diffusion layer 20, it is called a “non-flow path portion”. The gas flow paths 32 and 42 allow the reaction gas to flow from the reaction gas supply manifolds 470 and 480 described later to the reaction gas discharge manifolds 472 and 482 described later. In the anode-side separator 30, an anode-side gas flow path 32 is formed between a plurality of anode-side non-channel portions 36 on the anode-side surface of MEGA 21, and a plurality of streaky cooling medium flow paths 34 are formed on the opposite side thereof. Is formed. In the cathode side separator 40, a cathode side gas flow path 42 is formed between a plurality of cathode side non-channel portions 46 on the cathode side surface of MEGA 21, and the gas diffusion layer 20 is formed in both the cathode side non-channel portions 46. Are in contact. The separators 30 and 40 are formed, for example, by press-molding a metal plate made of stainless steel, titanium, or an alloy thereof.

FIG. 2 is a plan view showing a schematic configuration of the cathode side separator 30 in the present embodiment. The x direction in FIG. 2 corresponds to the "gas flow direction", and the z direction corresponds to the "stacking direction". FIG. 3 is a cross-sectional view of a fuel cell according to the present embodiment, and is a diagram for explaining a gas flow. As shown in FIG. 2, the cathode side separator 30 is, for example, a substantially rectangular plate-shaped member, a power generation region 50 facing MEGA 21 in the central portion, and a plurality of openings 470, 472, 480, 482 in the outer edge portion. 490 and 492 are provided. These openings 470, 472, 480, 482, 490, 492 are manifolds for the reaction gas and the cooling medium and are through holes that penetrate the thickness direction of the separator. Each manifold is arranged so that the flow direction of the fuel gas and the flow direction of the oxidant gas in the power generation region 50 face each other and intersect with each other with the electrolyte membrane 13 interposed therebetween. Specifically, the fuel gas supply manifold 470, the oxidizing agent gas supply manifold 480, and the cooling medium supply manifold 490 are arranged on the same side with respect to the power generation region 50, that is, on the right side of the paper surface, and the fuel gas discharge manifold 472 and the fuel gas discharge manifold 472. The oxidant gas discharge manifold 482 and the cooling medium discharge manifold 492 are arranged on the opposite side, that is, on the left side of the paper surface. The fuel gas and the oxidant gas, which are reaction gases, flow from the fuel gas supply manifold 470 or the oxidant gas supply manifold 480 toward the fuel gas discharge manifold 472 or the oxidant gas discharge manifold 482, respectively. Here, in the present specification, the fuel gas supply manifold 470 side of the anode side separator 30 or the oxidant gas supply manifold 480 side of the cathode side separator 40 is referred to as "upstream". Further, the fuel gas discharge manifold 472 side of the anode side separator 30 or the oxidant gas discharge manifold 482 side of the cathode side separator 40 is referred to as "downstream".

Here, the fuel gas supply manifold 470 and the fuel gas discharge manifold 472 are formed at positions diagonal to each other with the power generation region 50 interposed therebetween. The same applies to the oxidant gas supply manifold 480 and the oxidant gas discharge manifold 482, and the cooling medium supply manifold 490 and the cooling medium discharge manifold 492. The arrangement of the manifolds 470, 472, 480, 482, 490, and 492 for the reaction gas and the cooling medium may have other configurations.

Further, the cathode side separator 40 is formed with a cathode side gas flow path 42 extending linearly and parallel to each other along the gas flow direction (x direction in FIG. 2), and is between the cathode side gas flow paths 42. Is formed with a plurality of cathode-side non-channel portions 46 in a direction protruding toward the surface in contact with the gas diffusion layer 20, that is, in a stacking direction (z direction in FIG. 2). The height of the cathode-side non-flow path portion 46 in the stacking direction is constant in the direction orthogonal to the gas flow direction (y direction in FIG. 2). The width and cross-sectional area of each cathode side gas flow path 42 are constant except for the throttle portion 43, which will be described later. By making the cathode side gas flow path 42 linear, it is possible to increase the efficiency of discharging the liquid water generated by the electrochemical reaction in MEGA 21. The cathode side gas flow path 42 is preferably formed so as to penetrate straight between both ends of the power generation region 50 from the oxidant gas supply manifold 480 to the oxidant gas discharge manifold 482. With such a configuration, it is possible to more easily discharge the liquid water.

As shown in FIG. 2, the cathode side gas flow path 42 has a portion in which the cross-sectional area of the flow path is reduced by providing a protrusion in a direction orthogonal to the gas flow direction (y direction in FIG. 2). The cathode side non-flow path portion 46 adjacent to this portion is referred to as a throttle portion 43. Here, the cross-sectional area of the flow path means the cross-sectional area of one gas flow path among the plurality of cathode-side gas flow paths 42 provided in the cathode-side separator 40. In the cathode side non-flow path portion 46, the portion arranged adjacent to the upstream of the throttle portion 43 is the upstream portion 44. In the present embodiment, the cathode-side non-flow path portion 46 excluding the throttle portion 43 and the upstream portion 44 is the main portion 45. By providing a portion in the cathode side gas flow path 42 that reduces the cross-sectional area of the flow path, pressure loss occurs in the oxidant gas flowing through the cathode side gas flow path 42, and the flow rate of the oxidant gas becomes slow. Therefore, it stays in the upstream portion 44 arranged adjacent to the upstream of the throttle portion 43. By causing the oxidant gas to stay in the cathode side gas flow path 42 in this way, as shown in FIG. 3, the oxidant gas can be further submerged in the gas diffusion layer 20. Therefore, the oxidant gas easily diffuses into the gas diffusion layer 20, and the concentration of the oxidant gas in the cathode-side catalyst layer 12 in which the oxidant gas diffuses from the gas diffusion layer 20 can be improved.

FIG. 4 is an enlarged plan view of the region C shown in FIG. 2 and a cross-sectional view taken along the line AA of FIG. FIG. 4A is an enlarged plan view of the region C shown in FIG. Note that FIG. 4A shows an arrow indicating the flow of the oxidant gas in the cathode side separator 40. As shown in FIG. 4A, the cathode-side non-channel portion 46 is provided with a throttle portion 46 adjacent to a portion of the cathode-side gas flow path 42 in which the cross-sectional area of the flow path is reduced. As described above, since the provision of such a throttle portion 43 facilitates diffusion into the gas diffusion layer 20, the concentration of the oxidizing agent gas in the gas diffusion layer 20 changes from upstream to downstream in the gas flow direction. It becomes uniform at each stage. Therefore, it is possible to avoid deterioration of the power generation characteristics of the fuel cell 100. It is effective to provide such a throttle portion 43 downstream of the cathode side gas flow path 42 in which the concentration of the oxidant gas decreases.

FIG. 4B is a cross-sectional view of the cathode side non-channel portion 46 provided on the cathode side separator 40 in the line AA of FIG. 4A. FIG. 4C is a diagram in which the cathode side separator 43, the gas diffusion layer 20, and the membrane electrode assembly 10 are superposed. Here, the distance between the main portion 45 of the cathode side non-channel portion 46 and the membrane electrode assembly 10 is the first distance L1, and the cathode side non-channel portion 46 of the cathode side non-channel portion 46 adjacent to the throttle portion 43 is the cathode side non-channel portion. The distance between the portion 46 and the membrane electrode assembly 10 is the second distance L2, and the distance between the cathode side non-flow path portion 46 adjacent to the upstream portion 44 of the cathode side non-flow path portion 46 and the membrane electrode assembly 10 is the second. Let the distance L3 be 3. As shown in FIGS. 4 (b) and 4 (c), the cathode-side non-channel portion 46 formed in the cathode-side separator 40 in the present embodiment has a second distance L2 larger than that of the first distance L1. It is short and the third distance L3 is formed to be longer than the first distance L1. That is, the cathode-side non-channel portion 46 adjacent to the throttle portion 43 protrudes highest in the stacking direction with respect to the gas diffusion layer 20. On the other hand, the cathode-side non-channel portion 46 adjacent to the upstream portion 44 is the least protruding.

In the power generation region 50, the cathode side non-flow path portion 46 provided in the cathode side separator 43 is different from the first distance L1, the second distance L2, and the third distance L3 with respect to the membrane electrode assembly 10. By having three kinds of distances, the magnitude of the contact surface pressure acting on the gas diffusion layer 20 in contact with the cathode side separator 40 is different. Therefore, as shown in FIG. 4C, the thickness of the gas diffusion layer 20 with which the cathode-side non-channel portion 46 contacts varies depending on the location. Since the gas diffusion layer 20 is made of a porous base material for a diffusion layer, the higher the contact surface pressure acting on the gas diffusion layer 20, the smaller the thickness of the gas diffusion layer 20. When the thickness of the gas diffusion layer 20 is reduced, the porous base material having conductivity becomes denser, so that the electron conductivity is improved, while the porosity of the gas diffusion layer 20 is reduced, so that the gas diffusivity is lowered. .. Therefore, the distance between the main portion 45 and the membrane electrode assembly 10 is set to the first distance L1, which is the distance from the membrane electrode assembly 10 that can achieve both electron conductivity and gas diffusivity. In the present embodiment, the distance between the main portion 45 and the membrane electrode assembly 10 is constant at the first distance L1.

In the cathode side separator 40 in the present embodiment, as shown in FIG. 4C, the second distance L2 in the throttle portion 43 is shorter than the first distance L1 and the third distance L3. The thickness of the gas diffusion layer 20 is the thinnest. The second distance L2 is preferably 0.6 times or more and 0.9 times or less, and more preferably 0.7 times or more and 0.8 times or less the first distance L1. Therefore, since the contact surface pressure acting on the gas diffusion layer 20 in the throttle portion 43 becomes high, the porosity of the gas diffusion layer 20 becomes small, and the electron conductivity becomes good. However, in the throttle portion 43, the void ratio of the gas diffusion layer 20 becomes small, so that the oxidant gas is difficult to diffuse into the gas diffusion layer 20. Further, the cathode side gas flow path 42 adjacent to the throttle portion 43 has a reduced flow path cross-sectional area, and the pressure loss generated when the oxidant gas flows through the cathode side gas flow path 42 is large. .. As a result, the oxidant gas is more likely to stay in the upstream portion 44 adjacent to the upstream portion of the throttle portion 43.

Here, the third distance L3 in the upstream portion 44 is longer than the first distance L1 and the second distance L2, and the thickness of the gas diffusion layer 20 is the thickest. The third distance L3 is preferably 1.1 times or more and 1.3 times or less of the first distance L1, and more preferably 1.1 times or more and 1.2 times or less. Therefore, since the contact surface pressure acting on the gas diffusion layer 20 is low, the porosity of the gas diffusion layer 20 is large. Therefore, in the upstream portion 44 where the oxidant gas tends to stay, the oxidant gas tends to diffuse into the gas diffusion layer 20.

As described above, the cathode side separator 40 in the present embodiment increases the pressure loss generated in the cathode side gas flow path 42 in the throttle portion 43, while the oxidizing agent gas diffuses into the gas diffusion layer 20 in the upstream portion 44. The ease is also increased. As a result, the oxidant gas diffused in the gas diffusion layer 20 in the upstream portion 44 diffuses into the portion of the gas diffusion layer 20 facing the throttle portion 43. As a result, the concentration of the oxidant gas diffused in the gas diffusion layer 20 adjacent to the throttle portion 43 and the upstream portion 44 becomes uniform, and stable gas diffusibility can be obtained in the vicinity of the throttle portion 43. On the other hand, in the throttle portion 43, the contact surface pressure acting on the gas diffusion layer 20 is high, and the thickness of the gas diffusion layer 20 is thin, so that the electron conductivity is high. A throttle portion 43 having a high electron conductivity is located in the vicinity of the upstream portion 44 having a low contact surface pressure acting on the gas diffusion layer 20 and a low electron conductivity. As a result, stable electron conductivity can be obtained in the vicinity of the throttle portion 43. From the above, it is possible to achieve both electron conductivity and gas diffusivity in the vicinity of the throttle portion 43 of the cathode side separator 40.

In the above embodiment, the first distance of the cathode side non-flow path portion 46 adjacent to the throttle portion 43 is formed so as not to change, and the same applies to the second distance and the third distance. The present disclosure is not limited to this. 5 is an enlarged plan view of the region C shown in FIG. 2 in the modified example, and is a cross-sectional view taken along the line BB of FIG. 5A. 5 (a) is an enlarged plan view of the region C shown in FIG. 2 as in FIG. 4 (a). 5 (b) and 5 (c) are cross-sectional views taken along the line BB of FIG. 5 (a) in the modified example. As shown in FIG. 5B, the cathode side non-flow path portion 46 has a plane parallel to MEGA 21 having a second distance and a third distance, and a third distance or a second distance from the first distance. It may have a plane that is not perpendicular to MEGA 21 whose height changes continuously from to a third distance. In FIG. 5B, the cross section in the plane perpendicular to MEGA 21 is formed to be linear, but the cross section in the plane BB is not limited to this, and the plane whose height changes continuously is not limited to this. It may have an arc shape that is convex upward or convex downward. Further, as shown in FIG. 5C, the cross section of the cathode non-flow path portion 46 adjacent to the throttle portion 43 and the upstream portion 44 in a plane perpendicular to MEGA 21 may be arcuate. In such a form, it is possible to suppress the generation of a gap between the gas diffusion layer 20 and the gas diffusion layer 20. Therefore, the electron conductivity can be further improved.

In the above embodiment, the cathode side gas flow path 42 is a straight flow path extending linearly from the oxidant gas supply manifold 480 to the oxidant gas discharge manifold 482, but the present disclosure is not limited to this. For example, the cathode-side gas flow path 42 may be a serpentine flow path in which the gas flow direction is reversed a plurality of times. Further, the cathode side gas flow path 42 may meander to the extent that the throttle portion 43 is provided.

In the above embodiment, the throttle portion 43 provided in the cathode side gas flow path 42 has a direction in which the cathode side non-flow path portions 46 on both sides adjacent to the cathode side gas flow path 42 are orthogonal to the gas flow direction. By providing a protrusion protruding in the y direction in FIG. 2, the width of the cathode-side gas flow path 42 is reduced to reduce the cross-sectional area of the flow path, but the present disclosure is not limited to this. For example, of the cathode-side non-flow path portions 46 adjacent to the cathode-side gas flow path 42, only one of the cathode-side non-channel portions 46 is provided with a protrusion protruding in a direction orthogonal to the gas flow direction. The road cross-sectional area may be reduced. Further, the cathode side non-flow path portion 46 adjacent to the cathode side gas flow path 42 is not provided with a protrusion protruding in the direction orthogonal to the gas flow direction (y direction in FIG. 2), and the cathode side gas flow is not provided. The cross-sectional area of the flow path may be reduced by changing the height of the bottom of the road 42. Further, these may be combined as appropriate to reduce the cross-sectional area of the flow path of the cathode side gas flow path 42.

In the above embodiment, the throttle portion 43 is provided at a plurality of locations in each of the plurality of cathode side gas flow paths 42, but only one throttle portion 43 may be provided in each of the plurality of cathode side gas flow paths 42. However, one may be provided only in one cathode side gas flow path 42. The throttle portion 43 is preferably provided at a position other than the outlet of the cathode side gas flow path 42. As a result, it is possible to suppress the occurrence of a phenomenon in which the outlet of the cathode side gas flow path 42 is blocked by the liquid water and the oxidant gas is less likely to flow into the cathode side gas flow path 42.

In the above embodiment, the diaphragm portion 43 is provided symmetrically, but the present disclosure is not limited to this. As shown in FIG. 6, more throttle portions 43 may be provided downstream of the cathode side gas flow path 42 than upstream. Since the oxidant gas flowing through the cathode side gas flow path 42 diffuses into the gas diffusion layer 20, the gas concentration decreases toward the downstream side. According to this embodiment, the throttle portion 43 is provided on the downstream side where the gas concentration of the oxidant gas has decreased, and the cathode side non-channel portion 46 has a different contact surface pressure corresponding to the throttle portion 43. The height has been changed. Therefore, the oxidant gas can be efficiently diffused into the gas diffusion layer 20 with a small number of drawing portions 43.

In the above embodiment, the portion of the cathode-side non-flow path portion 46 excluding the throttle portion 43 and the upstream portion 44 is referred to as the main portion 45, but the present disclosure is not limited to this. The main portion 45 is arranged adjacent to the upstream portion 44 of the cathode side non-flow path portion 46, and the distance between the main portion 45 and the membrane electrode assembly 10 is the second distance L2 and the third. It may be a distance between the distance L3 and the distance L3.

In the above embodiment, the height of the cathode-side non-flow path portion 46 in the stacking direction is constant in the direction orthogonal to the gas flow direction, but the present disclosure is not limited to this. The height of the cathode-side non-flow path portion 46 in the stacking direction may be substantially constant in the direction orthogonal to the gas flow direction. Note that the height in the stacking direction is substantially constant in the direction orthogonal to the gas flow direction means that the stacking is within a predetermined range (-5% to + 5%) in the direction orthogonal to the gas flow direction. It means the height in the direction, and the height in the stacking direction may be constant in the direction orthogonal to the gas flow direction, or may be slightly changed.

In the above embodiment, the throttle portion 43 is provided in the cathode side gas flow path 42 formed in the cathode side separator 40, and the height of the cathode side non-flow path portion 46 is changed corresponding to the provided throttle portion 43. , This disclosure is not limited to this. It may be applied to the anode side gas flow path 32 formed in the anode side separator 30.

It should be noted that the present disclosure is not limited to the above embodiment, and can be realized by various configurations within a range not deviating from the gist thereof. For example, the technical features in the embodiments corresponding to the technical features in each embodiment described in the column of the outline of the invention are for solving a part or all of the above-mentioned problems, or one of the above-mentioned effects. It is possible to replace or combine as appropriate to achieve the part or all. Further, if the technical feature is not described as essential in the present specification, it can be appropriately deleted.

100 ... Fuel cell 10 ... Membrane electrode assembly 11 ... Cathode side catalyst layer 12 ... Cathode side catalyst layer 13 ... Electrolyte membrane 20 ... Gas diffusion layer 21 ... Membrane electrode gas diffusion layer assembly 30 ... Anodic side separator 32 ... Anode side Gas flow path 34 ... Cooling medium flow path 36 ... Anodic side non-flow path part 40 ... Cathode side separator 42 ... Cathode side gas flow path 43 ... Squeezing part 44 ... Upstream part 45 ... Main part 46 ... Cathode side non-flow path part 470 ... Fuel gas supply manifold 472 ... Fuel gas discharge manifold 480 ... Oxidating agent gas supply manifold 482 ... Oxidizing agent gas discharge manifold 490 ... Cooling medium supply manifold 492 ... Cooling medium discharge manifold 50 ... Power generation area

Claims (3)

A pair of gas diffusion layers, which are a porous base material for a diffusion layer, are arranged on both sides of the membrane electrode assembly and the membrane electrode assembly, and a pair of separators arranged on both sides of the pair of gas diffusion layers. A fuel cell with,
A reaction gas supply manifold and a reaction gas discharge manifold penetrating in the thickness direction are arranged in the pair of separators.
At least one of the pair of separators is provided with a plurality of gas flow paths for allowing the reaction gas to flow from the reaction gas supply manifold to the reaction gas discharge manifold.
In the plurality of gas flow paths, a plurality of non-channel portions that come into contact with the gas diffusion layer are provided between adjacent gas flow paths.
The non-flow path portion is continuously provided along the plurality of gas flow paths.
At least one non-flow path portion among the plurality of non-channel sections includes a throttle portion adjacent to a gas flow path having a first flow path cross section and a gas flow path having a second flow path cross section. Adjacent to each other, an upstream portion arranged adjacent to the upstream of the throttle portion and a main portion arranged adjacent to the upstream of the upstream portion are provided.
The first flow path cross section is smaller than the second flow path cross section.
Assuming that the distance between the main part and the membrane electrode assembly is the first distance,
It is formed so that the distance between the throttle portion and the membrane electrode assembly is a second distance shorter than the first distance.
A fuel cell cell characterized in that the distance between the upstream portion and the membrane electrode assembly is formed to be a third distance longer than the first distance. At least one non-flow path portion of the plurality of non-flow path portions is a surface parallel to the membrane electrode assembly having the second distance and the third distance in the throttle portion and the upstream portion. The fuel cell according to claim 1, wherein the fuel cell has a surface that is not perpendicular to the membrane electrode assembly whose height changes continuously up to the second distance or the third distance. .. At least one of the plurality of non-flow passage portions has a cross section in a plane perpendicular to the membrane electrode assembly of the non-channel portion and parallel to the gas flow direction. The fuel cell according to claim 1, wherein the portion and the upstream portion have an arc shape.

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