Air-cooled fuel cell

Abstract

The present application provides an air-cooled fuel cell capable of improving durability and power generation performance. The air-cooled fuel cell is characterized in that it has, in order, a second separator, a membrane electrode gas diffusion layer assembly, a first separator, and a cooling plate, the sum of the flow path width and the rib width of a third flow path is greater than the sum of the flow path width and the rib width of a first flow path and the sum of the flow path width and the rib width of a second flow path, the first separator, the second separator, and the cooling plate overlap the power generation region of the membrane electrode gas diffusion layer assembly in a plan view, at least a portion of the first flow path, the second flow path, and the third flow path cross each other, the angle θ 12 between the first flow path and the second flow path is 15° or more, the angle θ 13 between the first flow path and the third flow path is 40° or more, and the angle θ 23 between the second flow path and the third flow path is 40° or more.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an air-cooled fuel cell. BACKGROUND

[0002] A fuel cell (FC) is a power generation device configured of a single cell (hereinafter, there is a case where only a unit is described) or a fuel cell stack (hereinafter, there is a case where only a stack is described) in which a plurality of single cells are stacked, and which extracts electric energy by electrochemical reaction of a fuel gas such as hydrogen and an oxidant gas such as oxygen. In addition, the fuel gas and the oxidant gas actually supplied to the fuel cell are mostly a mixture with a gas that does not contribute to oxidation / reduction. In particular, the oxidant gas is mostly air containing oxygen.

[0003] In addition, hereinafter, there is a case where a fuel gas, an oxidant gas, and the like are simply referred to as “reaction gas” or “gas” without being particularly distinguished. In addition, there is a case where a single cell and a fuel cell stack in which single cells are stacked are both referred to as a fuel cell.

[0004] The single cell of the fuel cell generally has a membrane electrode assembly (MEA).

[0005] Various technologies have been proposed for a fuel cell used for a fuel cell vehicle (hereinafter, there is a case where only a vehicle is described) mounted on a vehicle.

[0006] For example, a solid polymer electrolyte fuel cell that does not impose an excessive load on a refrigerant supply system, can supply a reaction gas at a moderate flow rate, and can operate efficiently is disclosed in Patent Literature 1.

[0007] An electrode of a fuel cell that can rapidly discharge water accumulated in a diffusion layer and in which the diffusion layer is less likely to be damaged is disclosed in Patent Literature 2.

[0008] Patent Literature 1: Japanese Patent Application Publication No. 1998-308227

[0009] Patent Literature 2: Japanese Patent Application Publication No. 2007-299654

[0010] A flow path of a gas and a refrigerant of a fuel cell is formed by a recess, a groove, or the like provided in a separator. When a plurality of separators are stacked, if the separators that should originally be stacked with the convex portions of the recesses and the grooves facing each other are deviated and stacked, a shear force is applied to an electrolyte membrane and a gas diffusion layer that are components sandwiched by the separators, and a portion in which a load is increased and a portion in which the load is reduced are generated, thereby causing a decrease in performance and deterioration of the fuel cell.

[0011] In the separator of the water-cooled fuel cell, since it is a flow path of a relatively narrow groove pitch and two separators, if the flow paths cross each other, the above-mentioned problem does not occur. However, in the air-cooled fuel cell, the flow path of the cooling air needs a wide groove pitch flow path for heat transfer improvement and pressure loss reduction, the interval of the opposing protrusions becomes wide, and thus the region where the load is reduced easily becomes large. The same applies to the case where the cooling plate is provided separately from the separator and becomes a three-piece structure. SUMMARY

[0012] The present disclosure was completed in view of the above-described actual situation, and the main object thereof is to provide an air-cooled fuel cell capable of improving durability and power generation performance.

[0013] The air-cooled fuel cell of the present disclosure is characterized in that the air-cooled fuel cell has a first separator, a second separator, and a cooling plate, the first separator periodically has a plurality of first flow paths of a groove shape, the second separator periodically has a plurality of second flow paths of a groove shape, the cooling plate periodically has a plurality of third flow paths of a groove shape, the air-cooled fuel cell successively has the second separator, a membrane electrode gas diffusion layer assembly, the first separator, and the cooling plate, the sum of the flow path width and the rib width of the third flow path is larger than the sum of the flow path width and the rib width of the first flow path and the sum of the flow path width and the rib width of the second flow path, the power generation region in which the first separator, the second separator, and the cooling plate overlap the membrane electrode gas diffusion layer assembly in a plan view, at least a part of the first flow path, the second flow path, and the third flow path cross each other, the included angle θ 12 between the first flow path and the second flow path is 15° or more, the included angle θ 13 between the first flow path and the third flow path, and the included angle θ 23 between the second flow path and the third flow path is 40° or more.

[0014] It can also be configured that, on the basis of the air-cooled fuel cell of the present disclosure, at least either the first flow path or the second flow path is a wavy groove.

[0015] According to the air-cooled fuel cell of the present disclosure, it is possible to improve durability and power generation performance. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is the included angle θ 12 between the first flow path of the first separator and the second flow path of the second separator, the included angle θ 13 between the first flow path of the first separator and the third flow path of the cooling plate, and the included angle θ 23a graph of the respective intersection angles of the first flow path, the second flow path, and the third flow path with respect to the load disappearance angle Φ.

[0017] Figure 2 is an exploded perspective view showing an example of a single cell of the air-cooled fuel cell of the present disclosure.

[0018] Figure 3 is a schematic view showing the first flow path, the second flow path, and the third flow path of the fuel cell of Example 1 overlaid.

[0019] Figure 4 is a schematic view showing the first separator and the second separator of Example 1 overlaid.

[0020] Figure 5 is a schematic view showing the first separator and the cooling plate of Example 1 overlaid.

[0021] Figure 6 is a schematic view showing the second separator and the cooling plate of Example 1 overlaid.

[0022] Explanation of Reference Numerals

[0023] 11... air-cooled fuel cell (single cell); 12... first separator; 13... second separator; 14... resin frame; 15... cooling plate; 16... manifold; 21... first flow path; 22... second flow path; 23... third flow path; 31... rib portion of the first separator; 32... rib portion of the second separator; 33... rib portion of the cooling plate. DETAILED DESCRIPTION

[0024] The air-cooled fuel cell of the present disclosure is characterized in that the air-cooled fuel cell has a first separator, a second separator, and a cooling plate, the first separator periodically has a plurality of first flow paths that are grooves, the second separator periodically has a plurality of second flow paths that are grooves, the cooling plate periodically has a plurality of third flow paths that are grooves, the air-cooled fuel cell successively has the second separator, a membrane electrode gas diffusion layer assembly, the first separator, and the cooling plate, the sum of the flow path width and the rib portion width of the third flow path is greater than the sum of the flow path width and the rib portion width of the first flow path and the sum of the flow path width and the rib portion width of the second flow path, the first separator, the second separator, and the cooling plate overlap the power generation region of the membrane electrode gas diffusion layer assembly in a plan view, at least a portion of the first flow path, the second flow path, and the third flow path intersect each other,

[0025] the included angle θ of the first flow path and the second flow path 12 is 15° or more,

[0026] the included angle θ of the first flow path and the third flow path 13and the angle θ of the above-mentioned 2nd flow path and the above-mentioned 3rd flow path 23 is 40° or more.

[0027] In the flow path of the fuel cell, if there is an interface where the dents and the straight grooves overlap each other, when the stacking deviation occurs, the change in the ground contact area, the load concentration, the load disappearance, and the like occur at the interface, thereby causing the performance reduction, the deterioration, and the like of the fuel cell.

[0028] The change in the ground contact area affects the heat conduction, the resistance, the load distribution, and the like of the fuel cell.

[0029] For the load, for example, due to the increase in the local load, the flow path sinks into the GDL, thereby the pressure loss increases, the performance of the fuel cell reduces, and in the case where a plurality of unit cells are stacked, the performance difference occurs among the unit cells. In addition, due to the disappearance of the local load, the pressing of the electrolyte membrane disappears, and due to the expansion and contraction of the electrolyte membrane, the electrolyte membrane moves, thereby the electrolyte membrane cracks. Furthermore, due to the disappearance of the local load, the resistance and the heat conduction of the fuel cell deteriorate, and the local hot spot occurs, thereby the deterioration of the fuel cell accelerates.

[0030] If it is made a thick plate separator, the problems such as the change in the ground contact area, the load concentration, the load disappearance, and the like do not occur, but the productivity of the separator is poor, the separator is heavy, and the cost of the separator is high.

[0031] In the case of the water-cooled fuel cell, it is a problem between the respective flow paths of the two separators, but in the case of the air-cooled fuel cell, since it becomes a three-piece structure of the two separators and the cooling plate, it is necessary to suppress the occurrence of the change in the ground contact area, the load concentration, the load disappearance, and the like in the relationship between the respective flow paths.

[0032] In the present disclosure, in the air-cooled fuel cell having a reaction-use air flow path, a fuel gas flow path, and a cooling air flow path, the respective groove flow paths are arranged so as not to be parallel in the main region of the power generation portion. For example, the intersection angle of the reaction-use air flow path and the fuel gas flow path is made shallow, and the intersection angles of the reaction-use air flow path and the cooling air flow path and the fuel gas flow path and the cooling air flow path are made deep.

[0033] According to the present disclosure, in the power generation region of the fuel cell, it is possible to make the load applied to the electrolyte membrane, the gas diffusion layer, and the like more uniform than ever. Thereby, it is possible to reduce the damage to the electrolyte membrane, the gas diffusion layer, and the like, and as a result, it is possible to achieve the improvement of the durability and the power generation performance of the fuel cell.

[0034] In the present disclosure, fuel gas and oxidant gas are collectively referred to as reaction gas. The reaction gas supplied to the anode is fuel gas, and the reaction gas supplied to the cathode is oxidant gas. The fuel gas is a gas mainly containing hydrogen, and can be hydrogen gas. The oxidant gas can be oxygen gas, air, dry air, or the like.

[0035] The fuel cell of the present disclosure is an air-cooled fuel cell.

[0036] The air-cooled fuel cell uses air as a refrigerant. In the present disclosure, there is a case where air as a refrigerant is referred to as cooling air. In the present disclosure, there is a case where air as an oxidant gas is referred to as reaction air.

[0037] The air-cooled fuel cell has a first separator, a second separator, and a cooling plate.

[0038] Specifically, the air-cooled fuel cell has, in order, the second separator, a membrane electrode gas diffusion layer assembly, the first separator, and the cooling plate.

[0039] Specifically, the air-cooled fuel cell can have one single cell having, in order, the second separator, the membrane electrode gas diffusion layer assembly, the first separator, and the cooling plate, or can be a fuel cell stack in which a plurality of single cells are stacked.

[0040] The membrane electrode gas diffusion layer assembly (MEGA) has, in order, a first gas diffusion layer, a first catalyst layer, an electrolyte membrane, a second catalyst layer, and a second gas diffusion layer.

[0041] Specifically, the membrane electrode gas diffusion layer assembly has, in order, an anode-side gas diffusion layer, an anode catalyst layer, an electrolyte membrane, a cathode catalyst layer, and a cathode-side gas diffusion layer.

[0042] One of the first catalyst layer and the second catalyst layer is the cathode catalyst layer, and the other is the anode catalyst layer.

[0043] The cathode (oxidant electrode) includes the cathode catalyst layer and the cathode-side gas diffusion layer.

[0044] The anode (fuel electrode) includes the anode catalyst layer and the anode-side gas diffusion layer.

[0045] The first catalyst layer and the second catalyst layer are collectively referred to as catalyst layers. The cathode catalyst layer and the anode catalyst layer are collectively referred to as catalyst layers.

[0046] One of the first gas diffusion layer and the second gas diffusion layer is the cathode-side gas diffusion layer, and the other is the anode-side gas diffusion layer.

[0047] The first gas diffusion layer is a cathode-side gas diffusion layer in the case where the first catalyst layer is a cathode catalyst layer, and is an anode-side gas diffusion layer in the case where the first catalyst layer is an anode catalyst layer.

[0048] The second gas diffusion layer is a cathode-side gas diffusion layer in the case where the second catalyst layer is a cathode catalyst layer, and is an anode-side gas diffusion layer in the case where the second catalyst layer is an anode catalyst layer.

[0049] The first gas diffusion layer and the second gas diffusion layer are collectively referred to as a gas diffusion layer or a diffusion layer. The cathode-side gas diffusion layer and the anode-side gas diffusion layer are collectively referred to as a gas diffusion layer or a diffusion layer.

[0050] The gas diffusion layer can also be an electrically conductive member or the like having gas permeability.

[0051] As the electrically conductive member, for example, a carbon porous body such as carbon cloth and carbon paper, and a metal porous body such as a metal mesh and a foamed metal, or the like can be given.

[0052] The air-cooled fuel cell can also have a microporous layer (MPL) between the catalyst layer and the gas diffusion layer. The microporous layer can also include a mixture of a hydrophobic resin such as PTFE and an electrically conductive material such as carbon black.

[0053] The electrolyte membrane can also be a solid polymer electrolyte membrane. As the solid polymer electrolyte membrane, for example, a fluorine-based electrolyte membrane such as a thin film of a perfluorosulfonic acid containing moisture, and a hydrocarbon-based electrolyte membrane, or the like can be given. As the electrolyte membrane, for example, a perfluorosulfonic acid membrane (Nafion®, manufactured by DuPont) or the like can also be given.

[0054] One of the first separator and the second separator is a cathode-side separator, and the other is an anode-side separator.

[0055] The first separator is a cathode-side separator in the case where the first catalyst layer is a cathode catalyst layer, and is an anode-side separator in the case where the first catalyst layer is an anode catalyst layer.

[0056] The second separator is a cathode-side separator in the case where the second catalyst layer is a cathode catalyst layer, and is an anode-side separator in the case where the second catalyst layer is an anode catalyst layer.

[0057] The first separator and the second separator are collectively referred to as a separator. The anode-side separator and the cathode-side separator are collectively referred to as a separator.

[0058] The membrane-electrode-gas diffusion layer assembly is sandwiched by the first separator and the second separator.

[0059] The separator can also have a manifold such as a supply hole and a discharge hole for allowing a fluid such as a reaction gas and a refrigerant to flow in the stacking direction of the unit cells. As the refrigerant, air for cooling or the like can be used.

[0060] The supply hole can be exemplified by a fuel gas supply hole, an oxidizer gas supply hole, and a refrigerant supply hole.

[0061] The discharge hole can be exemplified by a fuel gas discharge hole, an oxidizer gas discharge hole, and a refrigerant discharge hole.

[0062] The separator can have one or more fuel gas supply holes, can have one or more oxidizer gas supply holes, can have one or more refrigerant supply holes as needed, can have one or more fuel gas discharge holes, can have one or more oxidizer gas discharge holes, and can have one or more refrigerant discharge holes as needed.

[0063] The separator can also be a gas-impermeable conductive member or the like. As the conductive member, for example, there can be a thermosetting resin, a thermoplastic resin, a resin material such as a resin fiber, a carbon composite material in which a mixture including a carbon material such as carbon powder and carbon fiber is press-formed, a dense carbon in which carbon is compressed to be gas-impermeable, and a press-formed metal (for example, titanium, iron, aluminum, and SUS) plate or the like. In addition, the separator can have a current collecting function.

[0064] The shape of the separator can be a rectangular shape, a horizontally long 6-sided shape, a horizontally long 8-sided shape, a circular shape, an oblong shape, or the like.

[0065] The first separator periodically has a plurality of first flow paths that are grooves. Specifically, the first separator periodically has grooves that become flow paths and rib portions alternately at a prescribed groove pitch.

[0066] The second separator periodically has a plurality of second flow paths that are grooves. Specifically, the second separator periodically has grooves that become flow paths and rib portions alternately at a prescribed groove pitch.

[0067] The groove pitch refers to a repeating unit of the sum of the groove width and the rib portion width. The groove pitch can be 1.0 to 1.8 mm, for example, or 1.2 to 1.6 mm.

[0068] At least either the first flow path or the second flow path can be a wavy groove, and both can be wavy grooves.

[0069] Either the first flow path or the second flow path can also be a straight groove.

[0070] The separator can also have a reaction gas flow path on the surface in contact with the gas diffusion layer. In addition, the separator can also have a refrigerant flow path for maintaining the temperature of the fuel cell constant on the surface on the side opposite to the surface in contact with the gas diffusion layer. The first flow path of the first separator can be at least either one of the reaction gas flow path and the refrigerant flow path, and both the reaction gas flow path and the refrigerant flow path can be the first flow path. The second flow path of the second separator can be at least either one of the reaction gas flow path and the refrigerant flow path, and both the reaction gas flow path and the refrigerant flow path can be the second flow path.

[0071] The separator can also have a gas distribution portion. The gas distribution portion is a portion disposed between the manifold and the flow path of the separator and diffuses or converges the gas flow from the manifold to the power generation region. In the case where the manifold is a supply hole, the gas distribution portion has a configuration that diffuses the gas flow. In the case where the manifold is a discharge hole, the gas distribution portion has a configuration that converges the gas flow.

[0072] In the case where the separator is an anode-side separator, there can be one or more fuel gas supply holes, there can be one or more oxidizing agent gas supply holes, there can be one or more refrigerant supply holes as needed, there can be one or more fuel gas discharge holes, there can be one or more oxidizing agent gas discharge holes, and there can be one or more refrigerant discharge holes as needed. The anode-side separator can have a fuel gas flow path that causes the fuel gas to flow from the fuel gas supply hole to the fuel gas discharge hole on the surface in contact with the anode-side gas diffusion layer, and can have a refrigerant flow path that causes the refrigerant to flow from the refrigerant supply hole to the refrigerant discharge hole on the surface on the side opposite to the surface in contact with the anode-side gas diffusion layer as needed.

[0073] In the case where the separator is a cathode-side separator, there can be one or more fuel gas supply holes, there can be one or more oxidizing agent gas supply holes, there can be one or more refrigerant supply holes as needed, there can be one or more fuel gas discharge holes, there can be one or more oxidizing agent gas discharge holes, and there can be one or more refrigerant discharge holes as needed. The cathode-side separator can have an oxidizing agent gas flow path that causes the oxidizing agent gas to flow from the oxidizing agent gas supply hole to the oxidizing agent gas discharge hole on the surface in contact with the cathode-side gas diffusion layer, and can have a refrigerant flow path that causes the refrigerant to flow from the refrigerant supply hole to the refrigerant discharge hole on the surface on the side opposite to the surface in contact with the cathode-side gas diffusion layer as needed.

[0074] The cooling plate periodically has a plurality of third flow paths in the form of grooves. Specifically, the cooling plate periodically has grooves and rib portions that become flow paths at a prescribed groove pitch alternately.

[0075] The third flow path can be a wavy groove, or can be a straight groove.

[0076] The cooling plate can also be a corrugated plate having a plurality of grooves that function as refrigerant flow paths.

[0077] The cooling plate can be a plate that is corrugated by bending processing of a metal plate such as aluminum, Ti, SUS, or the like. The cooling plate can also be electrically conductive treated on the surface with silver, nickel, carbon, or the like.

[0078] The grooves of the cooling plate can also be formed by bending processing.

[0079] The depth of the grooves can be, for example, 1.0 to 2.0 mm.

[0080] The bending processing can be, for example, embossing with a groove depth of 1.0 to 2.0 mm and a width of 1.0 to 2.0 mm at a pitch.

[0081] The cooling plate can also be disposed in a region that opposes the MEGA in the planar direction.

[0082] The cooling plate can also be disposed in a region other than a region in which a gasket is disposed between two adjacent single cells in the planar direction.

[0083] The cooling plate can also have a protruding portion that protrudes from the outer shape of the single cell.

[0084] The shape of the cooling plate can be, for example, a rectangular shape, a horizontally long 6-sided shape, a horizontally long 8-sided shape, a circular shape, an oblong shape, or the like.

[0085] The sum of the flow path width and the rib width of the third flow path of the cooling plate is greater than the sum of the flow path width and the rib width of the first flow path of the first separator and the sum of the flow path width and the rib width of the second flow path of the second separator.

[0086] The first separator, the second separator, and the cooling plate overlap a power generation region of the membrane-electrode gas diffusion layer assembly in a plan view, and at least a portion of the first flow path, the second flow path, and the third flow path cross each other. In the power generation region, at least a portion of the first flow path, the second flow path, and the third flow path can cross each other. From the viewpoint of improving the durability of the fuel cell, the first flow path, the second flow path, and the third flow path can also cross each other in the entire region of the power generation region.

[0087] The first separator, the second separator, and the cooling plate overlap a power generation region of the membrane-electrode gas diffusion layer assembly in a plan view, and at least a portion of the first flow path, the second flow path, and the third flow path cross each other. In the power generation region, at least a portion of the first flow path, the second flow path, and the third flow path can cross each other. From the viewpoint of improving the durability of the fuel cell, the first flow path, the second flow path, and the third flow path can also cross each other in the entire region of the power generation region.

[0088] Figure 1 is an angle θ 12 between the first flow path of the first separator and the second flow path of the second separator 13the angle θ of the first flow path of the first separator and the third flow path of the cooling plate 23 a graph of the relationship between the respective intersection angles and the load disappearance Φ.

[0089] the angle θ of the first flow path of the first separator and the second flow path of the second separator 12 may be 20° or more, or 90° or less, from the viewpoint of improving the durability of the fuel cell by reducing the load disappearance Φ.

[0090] the angle θ of the first flow path of the first separator and the third flow path of the cooling plate 13 the angle θ of the second flow path of the second separator and the third flow path of the cooling plate 23 may be 50° or more, or 90° or less, from the viewpoint of improving the durability of the fuel cell by reducing the load disappearance Φ.

[0091] By the first flow path, the second flow path, and the third flow path intersecting each other, when the first separator, the second separator, and the cooling plate, etc. are stacked with a deviation, the change in the ground area and the change in the load are small, the performance deviation between the single cells is reduced, and the reliability of the fuel cell can be improved with respect to the stacking deviation.

[0092] In the case of air cooling, in order to reduce the pressure loss of the refrigerant flow path, the refrigerant flow path of the cooling plate and the flow path of the separator become a relatively deep and wide groove shape. Therefore, the load disappearance region Φ 23 and Φ 13 easily become large. As shown in Figure 1 by making the angles θ 13 , θ 23 intersect relatively deeply to 40° or more, the load disappearance region can be reduced.

[0093] The fuel cell can also have a resin frame.

[0094] The resin frame can be configured to be disposed outside the membrane electrode gas diffusion layer assembly and between the first separator and the second separator.

[0095] In addition, the resin frame can be a member for preventing cross leakage and electrical shorting of the catalyst layers of the membrane electrode gas diffusion layer assembly.

[0096] The resin frame can have a skeleton portion, an opening portion, a supply hole, and a discharge hole.

[0097] The skeleton portion is the main portion of the resin frame that is connected to the membrane electrode gas diffusion layer assembly.

[0098] The opening portion is a holding region of the membrane-electrode-gas diffusion layer assembly, and is a through-hole that penetrates a portion of the skeleton portion in order to accommodate the membrane-electrode-gas diffusion layer assembly. The opening portion can be provided at a position in the resin frame where the skeleton portion is provided around (at the outer periphery of) the membrane-electrode-gas diffusion layer assembly, or the resin frame can have an opening portion in the center.

[0099] The supply hole and the discharge hole allow the reaction gas and the refrigerant and the like to flow in the stacking direction of the unit cell. The supply hole of the resin frame can be provided in alignment with the supply hole of the separator. The discharge hole of the resin frame can be provided in alignment with the discharge hole of the separator.

[0100] The resin frame can include a frame-shaped core layer, and two frame-shaped shell layers, i.e., a first shell layer and a second shell layer, provided on both faces of the core layer.

[0101] The first shell layer and the second shell layer can be provided in a frame shape on both faces of the core layer, like the core layer.

[0102] The core layer can be a structural member having gas sealing properties and insulation properties, and can be formed of a material that does not change in structure even under temperature conditions at the time of hot pressing in the manufacturing process of the fuel cell. Specifically, the material of the core layer can be, for example, a resin such as polyethylene, polypropylene, PC (polycarbonate), PPS (polyphenylene sulfide), PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PA (polyamide), PI (polyimide), PS (polystyrene), PPE (polyphenylene ether), PEEK (polyether ether ketone), a cyclic olefin, PES (polyether sulfone), PPSU (polyphenyl sulfone), LCP (liquid crystal polymer), an epoxy resin, or the like. The material of the core layer can be a rubber material such as EPDM (ethylene propylene diene rubber), a fluorine-based rubber, a silicone-based rubber, or the like.

[0103] From the viewpoint of ensuring insulation properties, the thickness of the core layer can be 5 μm or more, and can be 30 μm or more. From the viewpoint of reducing the thickness of the unit, the thickness of the core layer can be 200 μm or less, and can be 150 μm or less.

[0104] The first shell layer and the second shell layer have properties of having higher adhesion to other substances, softening under temperature conditions at the time of hot pressing, and having lower viscosity and melting point than the core layer, in order to adhere the core layer to the anode-side separator and the cathode-side separator to ensure sealing properties. Specifically, the first shell layer and the second shell layer can be a thermoplastic resin such as a polyester-based resin and a modified olefin-based resin, or can be a thermosetting resin such as a modified epoxy resin. The first shell layer and the second shell layer can be the same kind of resin as the adhesive layer.

[0105] The resin constituting the first shell layer and the resin constituting the second shell layer can be the same kind of resin or different kinds of resin. By providing the shell layers on both sides of the core layer, adhesion between the resin frame and the two separators based on heating and pressing becomes easy.

[0106] From the viewpoint of ensuring adhesion, the thickness of each of the first shell layer and the second shell layer can be 5 μm or more, or 20 μm or more, and from the viewpoint of reducing the thickness of the unit, can be 100 μm or less, or 40 μm or less.

[0107] In the resin frame, the first shell layer and the second shell layer can be provided only in the portions to be adhered to the anode-side separator and the cathode-side separator, respectively. The first shell layer provided on one side of the core layer can be adhered to the cathode-side separator. The second shell layer provided on the other side of the core layer can be adhered to the anode-side separator. Furthermore, the resin frame can be sandwiched by the pair of separators.

[0108] The air-cooled fuel cell can also have a gasket between the two adjacent unit cells.

[0109] The gasket can use ethylene-propylene-diene rubber (EPDM), silicone rubber, thermoplastic elastomer resin, or the like as a material.

[0110] Figure 2 is an exploded perspective view showing an example of a unit cell of the air-cooled fuel cell of the present disclosure.

[0111] The air-cooled fuel cell (unit cell) 11 has, in order, a cooling plate 15, a first separator 12, a resin frame 14 in which a MEGA is housed in an opening, and a second separator 13.

[0112] The cooling plate 15 is disposed in a region on the surface of the first separator 12 of the air-cooled fuel cell 11 that opposes the MEGA.

[0113] The first separator 12, the resin frame 14, and the second separator 13 are provided with an oxidant gas supply hole, an oxidant gas discharge hole, a fuel gas supply hole, and a fuel gas discharge hole that function as a manifold 16 through which air for use as an oxidant gas or hydrogen as a fuel gas flows as indicated by arrows.

[0114] The first separator 12 is provided with a plurality of groove-shaped first flow paths 21 that function as oxidant gas flow paths through which air for use as an oxidant gas flows as indicated by arrows.

[0115] The second separator 13 is provided with a plurality of groove-shaped second flow paths 22 that function as fuel gas flow paths through which hydrogen as a fuel gas flows as indicated by arrows.

[0116] The cooling fin 15 is provided with a plurality of third flow paths 23 that are groove-shaped and that become flow paths for the refrigerant through which cooling air as a refrigerant flows as indicated by arrows.

[0117] Further, the fuel cell can have a configuration in which the refrigerant flows on the side surface.

[0118]

EXAMPLE

[0119] (Example 1)

[0120] A single cell of a fuel cell was produced using the following first separator, second separator, and cooling plate.

[0121] • First separator: straight groove in the longitudinal direction (first flow path, reverse use air, 1.4 mm groove pitch)

[0122] • Second separator: wavy groove in the longitudinal direction with a 30-degree slope (second flow path, hydrogen, 1.5 mm groove pitch)

[0123] • Cooling plate: straight groove in the transverse direction (third flow path, cooling air, 3 mm groove pitch)

[0124] θ 12 = 30°, θ 13 = 90°, θ 23 = 60°.

[0125] Figure 3 is a schematic view of the first flow path, the second flow path, and the third flow path of the fuel cell of Example 1 being overlaid.

[0126] The first flow path 21 is a straight groove in the longitudinal direction.

[0127] The second flow path 22 is a wavy groove in the longitudinal direction.

[0128] The third flow path 23 is a straight groove in the transverse direction.

[0129] The first flow path 21, the second flow path 22, and the third flow path 23 cross each other.

[0130] Figure 4 is a schematic view of the first separator and the second separator of Example 1 being overlaid.

[0131] The rib portion 31 of the first separator and the rib portion 32 of the second separator cross at θ 12 = 30° in the same angle as the first flow path and the second flow path.

[0132] Φ 12Load disappearance Φ is the diameter of the largest circle that can be drawn in the region where the first separator and the second separator do not overlap. For example, the region where the rib 31 of the first separator and the rib 32 of the second separator overlap becomes a region where the upper and lower faces of the MEGA are pressed and constrained. On the other hand, the region that becomes a single-sided groove or a two-sided groove where the rib 31 of the first separator and the rib 32 of the second separator do not overlap is a region where the MEGA is not constrained, and the load disappearance Φ 12 is the diameter of the largest circle that can be drawn in the region where the first separator and the second separator do not overlap.

[0133] If compared with Figure 1 , the load disappearance Φ at θ 12 = 30° is 2.3 mm or less, the load distribution is uniform, and the desired durability of the fuel cell can be ensured.

[0134] Figure 5 is a schematic view in which the first separator and the cooling plate of Example 1 are overlaid.

[0135] The rib 31 of the first separator and the rib 33 of the cooling plate intersect at θ 13 = 90° with the same angle as the first flow path and the third flow path.

[0136] Φ 13 is the load disappearance that occurs between the first separator and the cooling plate. The load disappearance Φ 13 is the diameter of the largest circle that can be drawn in the region that becomes a single-sided groove or a two-sided groove where the rib 31 of the first separator and the rib 33 of the cooling plate do not overlap.

[0137] If compared with Figure 1 , the load disappearance Φ at θ 13 = 90° is 2.3 mm or less, the load distribution is uniform, and the desired durability of the fuel cell can be ensured.

[0138] Figure 6 is a schematic view in which the second separator and the cooling plate of Example 1 are overlaid.

[0139] The rib 32 of the second separator and the rib 33 of the cooling plate intersect at θ 23 = 60° with the same angle as the second flow path and the third flow path.

[0140] Φ 23 is the load disappearance that occurs between the second separator and the cooling plate. The load disappearance Φ 23 is the diameter of the largest circle that can be drawn in the region that becomes a single-sided groove or a two-sided groove where the rib 32 of the second separator and the rib 33 of the cooling plate do not overlap.

[0141] If compared with Figure 1 , the load disappearance Φ at θ 23The load disappearance Φ is 2.3 mm or less, the load is uniformly distributed, and the desired durability of the fuel cell can be ensured.

[0142] It can be determined that if the load disappearance Φ is 2.3 mm or less, the desired durability of the fuel cell is obtained, and it can be said that the smaller the load disappearance Φ, the higher the durability of the fuel cell.

Claims

1. An air-cooled fuel cell, characterized by comprising: the air-cooled fuel cell has a first separator, a second separator, and a cooling plate, the first separator periodically has a plurality of first flow paths which are grooves, the second separator periodically has a plurality of second flow paths which are grooves, the cooling plate periodically has a plurality of third flow paths which are grooves, the air-cooled fuel cell has the second separator, a membrane electrode gas diffusion layer assembly, the first separator, and the cooling plate in this order, the sum of the flow path width and the rib width of the third flow path is larger than the sum of the flow path width and the rib width of the first flow path and the sum of the flow path width and the rib width of the second flow path, in a power generation region in which the first separator, the second separator, and the cooling plate overlap the membrane electrode gas diffusion layer assembly in a plan view, at least a part of the first flow paths, the second flow paths, and the third flow paths cross each other, the first flow path is a straight groove in the long direction, and has a groove and a rib which become a flow path, the second flow path is a wavy groove in the long direction, and has a groove and a rib which become a flow path, the third flow path is a straight groove in the short direction, and has a groove and a rib which become a flow path The angle θ of the first flow path and the second flow path 12 30°, the angle of the rib of the first flow path and the rib of the second flow path is 30°, The angle θ of the first flow path and the third flow path 13 is 90°, and the angle of the rib of the first flow path and the rib of the third flow path is 90°, The angle θ of the second flow path and the third flow path 23 is 60°, and the angle of the rib portion of the second flow path and the rib portion of the third flow path is 60°, by so configuring, the load generated between the first separator and the second separator disappears, the load generated between the first separator and the cooling plate disappears, and the load generated between the second separator and the cooling plate disappears, each being 2.3 mm or less, wherein the load generated between the first separator and the second separator disappearing means that the diameter of the largest circle drawn in a region of a single-sided groove or a double-sided groove in which the ribs of the first separator and the ribs of the second separator do not overlap and in which the membrane electrode gas diffusion layer assembly is not constrained, the load generated between the first separator and the cooling plate disappearing means that the diameter of the largest circle drawn in a region of a single-sided groove or a double-sided groove in which the ribs of the first separator and the ribs of the cooling plate do not overlap, the load generated between the second separator and the cooling plate disappearing means that the diameter of the largest circle drawn in a region of a single-sided groove or a double-sided groove in which the ribs of the second separator and the ribs of the cooling plate do not overlap.

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