Power generation cells and fuel cell stacks

Abstract

To provide a power generation cell and a fuel cell stack which can effectively prevent leakage of fluid while suppressing manufacturing cost.SOLUTION: A power generation cell 10 of a fuel cell stack 12 includes a tunnel 76a for making a cooling medium supply communication hole 18a and a cooling medium flow passage 70 communicate each other. The tunnel has a first projection projecting toward a resin frame part 30 from a first metal separator 22, and a first arrangement part including a first seal arrangement surface where a first resin seal member 48 is arranged. The first seal arrangement surface is positioned in a direction opposite to the resin frame part with respect to a first end face in a projection direction of the first projection.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to power generating cells and fuel cell stacks. [Background technology]

[0002] In recent years, research and development into fuel cell stacks has been conducted to contribute to energy efficiency, ensuring that more people have access to affordable, reliable, sustainable and advanced energy.

[0003] For example, Patent Document 1 discloses a power generation cell including a resin-framed membrane electrode assembly and metal separators disposed on both sides of the resin-framed membrane electrode assembly, in which seals are provided to prevent leakage of fluids such as oxidant gas, fuel gas, or cooling medium. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-149486 Summary of the Invention [Problem to be solved by the invention]

[0005] There is a demand for a power generation cell and a fuel cell stack that can effectively prevent fluid leakage while keeping manufacturing costs low.

[0006] The present disclosure aims to solve the above-mentioned problems. [Means for solving the problem]

[0007] A first aspect of the present disclosure provides a fuel cell comprising: a resin-framed membrane electrode assembly having a membrane electrode assembly formed by arranging electrodes on both sides of an electrolyte membrane; a resin frame portion protruding outward from the outer periphery of the membrane electrode assembly and surrounding the membrane electrode assembly; metal separators arranged on both sides of the resin-framed membrane electrode assembly; and an elastically deformable resin sealing member arranged between the resin frame portion and the metal separator, wherein the metal separator has fluid communication holes for circulating a fluid such as an oxidant gas, a fuel gas, or a cooling medium in a thickness direction of the metal separator; a power generation cell provided with a fluid flow path that allows fluid to flow in the surface direction of a metal separator, and a tunnel that connects the fluid communication hole and the fluid flow path to each other, wherein the resin seal member is arranged to straddle the tunnel in a direction that intersects with the flow direction of the fluid flowing inside the tunnel, the tunnel has a convex portion that protrudes from the metal separator toward the resin frame portion, and an arrangement portion that includes a seal arrangement surface on which the resin seal member is arranged, and the seal arrangement surface is located in the opposite direction from the resin frame portion relative to the end face in the protruding direction of the convex portion.

[0008] A second aspect of the present disclosure is a fuel cell stack in which a plurality of power generating cells according to the first aspect are stacked. [Effects of the Invention]

[0009] According to the present disclosure, it is possible to effectively prevent fluid leakage while reducing manufacturing costs. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is an exploded perspective view of a fuel cell stack according to one embodiment of the present invention. [Figure 2] FIG. 2 is a plan view of the first metal separator. [Figure 3] FIG. 3 is a plan view of the second metal separator. [Figure 4] FIG. 4 is a cross-sectional perspective view of the cooling medium inlet. [Figure 5]FIG. 5 is a cross-sectional view taken along line VV in FIG. [Figure 6] FIG. 6 is a cross-sectional perspective view of the coolant inlet portion. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] A power generating cell 10 and a fuel cell stack 12 according to one embodiment of the present invention will be described below with reference to the drawings. The fuel cell stack 12 according to this embodiment is mounted, for example, on a vehicle (not shown). The use of the fuel cell stack 12 is not particularly limited.

[0012] 1, the fuel cell stack 12 is formed by stacking a plurality of power generation cells 10 one on top of another in the direction of arrow A. A compressive load (clamping load) is applied to the power generation cells 10 in the stacking direction (direction of arrow A) by fastening members or the like (not shown).

[0013] The power generating cell 10 is formed in a horizontally long rectangular shape. The shape of the power generating cell 10 is not particularly limited, and may be formed in, for example, a vertically long rectangular shape or a square shape. The power generating cell 10 generates power through an electrochemical reaction between a fuel gas, which is one reactant gas, and an oxidant gas, which is the other reactant gas. The fuel gas is, for example, a hydrogen-containing gas. The oxidant gas is, for example, an oxygen-containing gas. A cooling medium for cooling the power generating cell 10 flows through the power generating cell 10. The cooling medium is, for example, pure water, ethylene glycol, oil, etc.

[0014] Each power generation cell 10 has an oxidant gas supply communication hole 14a, an oxidant gas discharge communication hole 14b, a fuel gas supply communication hole 16a, a fuel gas discharge communication hole 16b, a cooling medium supply communication hole 18a, and a cooling medium discharge communication hole 18b formed therethrough in the stacking direction (direction of arrow A).

[0015] An oxidant gas supply passage 14a, a coolant supply passage 18a, and a fuel gas discharge passage 16b are provided at one edge of the long side (the edge in the direction of arrow B1) of the power generation cell 10. The oxidant gas supply passage 14a, the coolant supply passage 18a, and the fuel gas discharge passage 16b are aligned in the direction of the short side of the power generation cell 10 (the direction of arrow C).

[0016] Oxidant gas flows through the oxygen-containing gas supply passage 14a in the direction of arrow A2. Coolant flows through the coolant supply passage 18a in the direction of arrow A2. Fuel gas flows through the fuel gas discharge passage 16b in the direction of arrow A1.

[0017] A fuel gas supply passage 16a, a coolant discharge passage 18b, and an oxygen-containing gas discharge passage 14b are provided at the other long edge (the edge in the direction of arrow B2) of the power generation cell 10. The fuel gas supply passage 16a, the coolant discharge passage 18b, and the oxygen-containing gas discharge passage 14b are aligned in the direction of arrow C.

[0018] Fuel gas flows through the fuel gas supply passage 16a in the direction of arrow A2. Coolant flows through the coolant discharge passage 18b in the direction of arrow A1. Oxidant gas flows through the oxidant gas discharge passage 14b in the direction of arrow A1.

[0019] The oxidant gas supply passage 14a, the oxidant gas discharge passage 14b, the fuel gas supply passage 16a, the fuel gas discharge passage 16b, the coolant supply passage 18a, and the coolant discharge passage 18b are fluid passages that allow a fluid such as an oxidant gas, a fuel gas, or a coolant to flow in the direction of arrow A. The arrangement, shape, and size of the oxidant gas supply passage 14a, the oxidant gas discharge passage 14b, the fuel gas supply passage 16a, the fuel gas discharge passage 16b, the coolant supply passage 18a, and the coolant discharge passage 18b may be set appropriately according to required specifications.

[0020] The power generation cell 10 includes a resin-framed membrane electrode assembly 20, a first metal separator 22, and a second metal separator 24. The first metal separator 22 is disposed on one surface (the surface in the direction of arrow A2) of the resin-framed membrane electrode assembly 20. The second metal separator 24 is disposed on the other surface (the surface in the direction of arrow A1) of the resin-framed membrane electrode assembly 20. The first metal separator 22 and the second metal separator 24 sandwich the resin-framed membrane electrode assembly 20 from the direction of arrow A.

[0021] The first metal separator 22 and the second metal separator 24 are joined together to form a joined separator 26. The joined separator 26 is provided with a joining line (not shown) that joins the first metal separator 22 and the second metal separator 24 together in an airtight and liquidtight manner. The joining line surrounds the outer periphery of the joined separator 26. The joining line also surrounds each fluid communication hole (such as the oxidant gas supply communication hole 14a). The resin-framed membrane electrode assemblies 20 and the joined separators 26 are alternately stacked in the direction of arrow A.

[0022] The resin-framed membrane electrode assembly 20 has a membrane electrode assembly 28 (MEA: Membrane Electrode Assembly) and a resin frame portion 30. The membrane electrode assembly 28 includes an electrolyte membrane 32, a first electrode 34, and a second electrode 36. The electrolyte membrane 32 is, for example, a solid polymer electrolyte membrane (cation exchange membrane). The solid polymer electrolyte membrane is, for example, a thin film of perfluorosulfonic acid containing water. The electrolyte membrane 32 can be a fluorine-based electrolyte or an HC (hydrocarbon)-based electrolyte. The electrolyte membrane 32 is sandwiched between the first electrode 34 and the second electrode 36.

[0023] The first electrode 34 is an anode electrode provided on one surface (the surface in the direction of arrow A2) of the electrolyte membrane 32. The second electrode 36 is a cathode electrode provided on the other surface (the surface in the direction of arrow A1) of the electrolyte membrane 32. The first metal separator 22 is disposed to face the first electrode 34. The second metal separator 24 is disposed to face the second electrode 36.

[0024] The first electrode 34 has a first electrode catalyst layer and a first gas diffusion layer. The first electrode catalyst layer is bonded to one side of the electrolyte membrane 32. The first gas diffusion layer is laminated on the first electrode catalyst layer. The second electrode 36 has a second electrode catalyst layer and a second gas diffusion layer. The second electrode catalyst layer is bonded to the other side of the electrolyte membrane 32. The second gas diffusion layer is laminated on the second electrode catalyst layer. The first gas diffusion layer and the second gas diffusion layer are each made of carbon paper, carbon cloth, or the like.

[0025] The fuel gas flowing through the fuel gas supply passage 16a is guided between the first metal separator 22 and the resin-framed membrane electrode assembly 20, and is thereby supplied to the first electrode 34. The oxidant gas flowing through the oxidant gas supply passage 14a is guided between the second metal separator 24 and the resin-framed membrane electrode assembly 20, and is thereby supplied to the second electrode 36. The power generation cell 10 generates electricity using the fuel gas supplied to the first electrode 34 and the oxidant gas supplied to the second electrode 36.

[0026] The fuel gas that flows between the first metal separator 22 and the resin-framed membrane electrode assembly 20 is guided to the fuel gas discharge passage 16b. The oxidant gas that flows between the second metal separator 24 and the resin-framed membrane electrode assembly 20 is guided to the oxidant gas discharge passage 14b. The coolant that flows through the coolant supply passage 18a flows between the first metal separator 22 and the second metal separator 24 and is guided to the coolant discharge passage 18b.

[0027] The resin frame 30 is a frame-shaped sheet that surrounds the outer periphery of the membrane electrode assembly 28. The inner periphery of the resin frame 30 is sandwiched between the outer periphery of the membrane electrode assembly 28. The resin frame 30 has electrical insulation properties.

[0028] Examples of materials that can be used to form the resin frame 30 include PPS (polyphenylene sulfide), PPA (polyphthalamide), PEN (polyethylene naphthalate), PES (polyethersulfone), LCP (liquid crystal polymer), PVDF (polyvinylidene fluoride), silicone resin, fluororesin, m-PPE (modified polyphenylene ether resin), PET (polyethylene terephthalate), PBT (polybutylene terephthalate), and modified polyolefin.

[0029] The oxygen-containing gas supply passage 14a, the coolant supply passage 18a, and the fuel gas discharge passage 16b are provided at one edge (the edge in the direction of arrow B1) of the resin frame 30. The fuel gas supply passage 16a, the coolant discharge passage 18b, and the oxygen-containing gas discharge passage 14b are provided at the other edge (the edge in the direction of arrow B2) of the resin frame 30.

[0030] The resin frame portion 30 of the resin-framed membrane electrode assembly 20 may be formed by making the electrolyte membrane 32 protrude outward beyond the outer peripheries of the first electrode 34 and the second electrode 36 .

[0031] As shown in FIGS. 1 and 2, the first metal separator 22 is formed in a plate shape. The first metal separator 22 is, for example, a thin metal plate such as a steel plate, a stainless steel plate, or an aluminum plate. The first metal separator 22 may be subjected to anti-corrosion treatment. The first metal separator 22 is formed in a rectangular shape. One end edge portion (the end edge portion in the direction of arrow B1) of the first metal separator 22 is provided with an oxygen-containing gas supply passage 14a, a coolant supply passage 18a, and a fuel gas discharge passage 16b. The other end edge portion (the end edge portion in the direction of arrow B2) of the first metal separator 22 is provided with a fuel gas supply passage 16a, a coolant discharge passage 18b, and an oxygen-containing gas discharge passage 14b. The first metal separator 22 is formed by press-forming a metal plate.

[0032] The first metal separator 22 has a first surface 22a facing the resin-framed membrane electrode assembly 20 and a first back surface 22b facing the second metal separator 24 of the power generating cell 10 adjacent to the first metal separator 22.

[0033] As shown in FIG. 2, a first gas flow path (fluid flow path) 38 is formed on the first surface 22a of the first metal separator 22. The first gas flow path 38 is a fuel gas flow path that distributes fuel gas along the first electrode 34. The first gas flow path 38 includes a plurality of first flow path convex portions 40 and a plurality of first flow path grooves 42. The first flow path convex portions 40 and the first flow path grooves 42 are alternately arranged in the direction of arrow C. Each of the first flow path convex portions 40 and the first flow path grooves 42 extends linearly in the direction of arrow B. Alternatively, each of the first flow path convex portions 40 and the first flow path grooves 42 may extend in a wavy manner in the direction of arrow B.

[0034] The first gas flow path 38 communicates with the fuel gas supply passage 16a via a fuel gas inlet 44. The first gas flow path 38 communicates with the fuel gas discharge passage 16b via a fuel gas outlet 46. The detailed configurations of the fuel gas inlet 44 and the fuel gas outlet 46 will be described later.

[0035] A first resin sealing member 48 is disposed between the first metal separator 22 and the resin frame 30. The first resin sealing member 48 is fixed to the first surface 22a of the first metal separator 22. Specifically, the first resin sealing member 48 is formed, for example, by applying a liquid resin material to the first surface 22a by screen printing. The first resin sealing member 48 may also be formed by applying the liquid resin material to the first surface 22a using a dispenser. The first resin sealing member 48 may also be formed by adhering a solid resin material, which has been formed into a predetermined shape in advance, to the first surface 22a with an adhesive or the like. The first resin sealing member 48 may also be fixed to the resin frame 30.

[0036] The first resin seal member 48 prevents leakage of fluid such as oxidant gas, fuel gas, or coolant from between the resin-framed membrane electrode assembly 20 and the first metal separator 22. The first resin seal member 48 is made of a rubber material. Examples of materials that can be used for the first resin seal member 48 include EPDM (ethylene-propylene rubber), NBR, silicone rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroprene, and acrylic rubber. The first resin seal member 48 has a rectangular cross section.

[0037] The first resin seal member 48 includes a plurality of first communication hole seals 50a-50f and a first flow path seal 52. The first communication hole seal 50a surrounds the fuel gas supply passage 16a. The first communication hole seal 50b surrounds the fuel gas discharge passage 16b. The first communication hole seal 50c surrounds the oxygen-containing gas supply passage 14a. The first communication hole seal 50d surrounds the oxygen-containing gas discharge passage 14b. The first communication hole seal 50e surrounds the coolant supply passage 18a. The first communication hole seal 50f surrounds the coolant discharge passage 18b. Hereinafter, the plurality of first communication hole seals 50a-50f may be simply referred to as "first communication hole seals 50."

[0038] The first flow path seal portion 52 surrounds the first communication hole seal portions 50a to 50d and the first gas flow path 38. The first communication hole seal portions 50e and 50f are located outside the first flow path seal portion 52.

[0039] As shown in FIGS. 1 and 3, the second metal separator 24 is formed in a plate shape. The second metal separator 24 is, for example, a thin metal plate such as a steel plate, a stainless steel plate, or an aluminum plate. The second metal separator 24 may be subjected to a corrosion prevention treatment. The second metal separator 24 is formed in a rectangular shape. One end edge of the second metal separator 24 (the end edge in the direction of arrow B1) is provided with an oxygen-containing gas supply passage 14a, a coolant supply passage 18a, and a fuel gas discharge passage 16b. The other end edge of the second metal separator 24 (the end edge in the direction of arrow B2) is provided with a fuel gas supply passage 16a, a coolant discharge passage 18b, and an oxygen-containing gas discharge passage 14b. The second metal separator 24 is formed by press-forming a metal plate.

[0040] The second metal separator 24 has a second front surface 24a facing the resin-framed membrane electrode assembly 20 and a second back surface 24b facing the first metal separator 22 of the adjacent power generating cell 10.

[0041] As shown in FIG. 3 , a second gas flow path (fluid flow path) 54 is formed on the second surface 24a of the second metal separator 24. The second gas flow path 54 is an oxidant gas flow path that circulates the oxidant gas along the second electrode 36. The second gas flow path 54 includes a plurality of second flow path convex portions 56 and a plurality of second flow path grooves 58. The second flow path convex portions 56 and the second flow path grooves 58 are alternately arranged in the direction of arrow C. Each of the second flow path convex portions 56 and the second flow path grooves 58 extends linearly in the direction of arrow B. Alternatively, each of the second flow path convex portions 56 and the second flow path grooves 58 may extend in a wavy manner in the direction of arrow B.

[0042] The second gas flow path 54 communicates with the oxidant gas supply passage 14a via an oxidant gas inlet 60. The second gas flow path 54 communicates with the oxidant gas discharge passage 14b via an oxidant gas outlet 62. The detailed configurations of the oxidant gas inlet 60 and the oxidant gas outlet 62 will be described later.

[0043] A second resin sealing member 64 is disposed between the second metal separator 24 and the resin frame 30. The second resin sealing member 64 is fixed to the second surface 24a of the second metal separator 24. Specifically, the second resin sealing member 64 is formed, for example, by applying a liquid resin material to the second surface 24a by screen printing. The second resin sealing member 64 may also be formed by applying the liquid resin material to the second surface 24a using a dispenser. The second resin sealing member 64 may also be formed by adhering a solid resin material, which has been formed into a predetermined shape in advance, to the second surface 24a with an adhesive or the like. The second resin sealing member 64 may also be fixed to the resin frame 30.

[0044] The second resin seal member 64 prevents leakage of fluid such as oxidant gas, fuel gas, or coolant from between the resin-framed membrane electrode assembly 20 and the second metal separator 24. The second resin seal member 64 is made of a rubber material. Examples of materials that can be used to form the second resin seal member 64 include the same materials as those used to form the first resin seal member 48. The second resin seal member 64 has a rectangular cross section.

[0045] The second resin seal member 64 includes a plurality of second communication hole seals 66a-66f and a second flow path seal 68. The second communication hole seal 66a surrounds the fuel gas supply passage 16a. The second communication hole seal 66b surrounds the fuel gas discharge passage 16b. The second communication hole seal 66c surrounds the oxygen-containing gas supply passage 14a. The second communication hole seal 66d surrounds the oxygen-containing gas discharge passage 14b. The second communication hole seal 66e surrounds the coolant supply passage 18a. The second communication hole seal 66f surrounds the coolant discharge passage 18b. Hereinafter, the plurality of second communication hole seals 66a-66f may be referred to as "second communication hole seals 66."

[0046] The second flow path seal portion 68 surrounds the second communication hole seal portions 66a to 66d and the second gas flow path 54. The second communication hole seal portions 66e and 66f are located outside the second flow path seal portion 68.

[0047] 1, a coolant flow field (fluid flow field) 70 is formed between the first back surface 22b of the first metal separator 22 and the second back surface 24b of the second metal separator 24. The coolant flow field 70 is formed by the back surface shape of the first gas flow field 38 and the back surface shape of the second gas flow field 54.

[0048] The coolant flow field 70 communicates with the coolant supply passage 18a via a coolant inlet 72. The coolant flow field 70 communicates with the coolant discharge passage 18b via a coolant outlet 74.

[0049] As shown in Figures 4 to 7, the coolant introduction section 72 has a plurality of tunnels 76a. As shown in Figures 4 and 6, the tunnels 76a extend linearly in the direction of arrow B. The plurality of tunnels 76a are arranged at intervals in the direction of arrow C. In this embodiment, the coolant introduction section 72 has four tunnels 76a. The number of tunnels 76a can be set appropriately, and may be one or more (other than four).

[0050] The tunnel 76a includes a first tunnel wall 78 and a second tunnel wall 80. The first tunnel wall 78 is provided in the first metal separator 22. The second tunnel wall 80 is provided in the second metal separator 24. A communication passage 82 through which a coolant flows is formed between the first tunnel wall 78 and the second tunnel wall 80 in the direction of arrow B2. The communication passage 82 has a first bent portion 84 and a second bent portion 86. The first bent portion 84 is inclined in the direction of arrow A2 toward the direction of arrow B2. The second bent portion 86 is inclined in the direction of arrow A1 toward the direction of arrow B2.

[0051] 4, the first tunnel wall 78 includes a first protrusion 88, a second protrusion 90, and a first arrangement portion 92. The first protrusion 88 and the second protrusion 90 are formed integrally with the first metal separator 22 by press-forming a metal plate. The first protrusion 88 extends from the coolant supply passage 18a toward the coolant flow field 70 (in the direction of arrow B2) (see FIG. 2). The first protrusion 88 protrudes from the first surface 22a of the first metal separator 22 toward the resin frame 30 (in the direction of arrow A1).

[0052] 4 and 7, the first protrusion 88 has a trapezoidal cross section in a direction perpendicular to the stacking direction of the power generation cells 10. The internal space of the first protrusion 88 forms the communication passage 82. The end of the first protrusion 88 in the direction of arrow B1 opens into the coolant supply passage 18a. A first end face 100 of the first protrusion 88 in the protruding direction is in contact with or close to the resin frame 30 adjacent to the first metal separator 22.

[0053] 4, the second protrusion 90 is located a predetermined distance away from the first protrusion 88 in the direction of arrow B2. The second protrusion 90 has a trapezoidal cross section in a direction perpendicular to the stacking direction of the power generation cells 10. The internal space of the second protrusion 90 forms the communication passage 82. A second end face 108 in the protruding direction of the second protrusion 90 is in contact with or close to the resin frame 30 adjacent to the first metal separator 22.

[0054] The first arrangement portion 92 connects the end of the first protrusion 88 in the direction of arrow B2 and the end of the second protrusion 90 in the direction of arrow B1. The first arrangement portion 92 has a first seal arrangement surface 110 on which the first resin seal member 48 is arranged. The first seal arrangement surface 110 faces the resin frame 30 (in the direction of arrow A1). The first communication hole seal portion 50e and the first flow path seal portion 52 are arranged on the first seal arrangement surface 110. The first communication hole seal portion 50e and the first flow path seal portion 52 are arranged so as to straddle the tunnel 76a in a direction (in the direction of arrow C) that intersects the flow direction of the coolant flowing through the interior of the tunnel 76a (communicating passage 82) (see FIGS. 4 and 5).

[0055] The first seal arrangement surface 110 is located in the opposite direction (the direction of arrow A2) from the resin frame 30 relative to the first end surface 100 and the second end surface 108. The first seal arrangement surface 110 is formed flat and is connected to the first surface 22a of the first metal separator 22 so as to be flush with it.

[0056] 6, the second tunnel wall portion 80 has a third convex portion 112 and a second arrangement portion 114. The third convex portion 112 is formed integrally with the second metal separator 24 by press-forming a metal plate. The third convex portion 112 extends in the direction of arrow B. The third convex portion 112 protrudes from the second surface 24a of the second metal separator 24 toward the resin frame portion 30 (in the direction of arrow A2).

[0057] 5 and 6, the third protrusion 112 has a trapezoidal cross section in a direction perpendicular to the stacking direction of the power generation cells 10. The third protrusion 112 and the first arrangement portion 92 face each other while being spaced apart from each other. The internal space of the third protrusion 112 forms the communication path 82. The internal space of the third protrusion 112 communicates with the internal space of the first protrusion 88 and the internal space of the second protrusion 90. A third end surface 124 in the protruding direction of the third protrusion 112 is in contact with or close to the resin frame 30 adjacent to the second metal separator 24.

[0058] As shown in FIG. 6, the second arrangement portion 114 has a second seal arrangement surface 126 on which the second resin seal member 64 is arranged. The second arrangement portion 114 includes an outer arrangement portion 128 and an inner arrangement portion 130. The outer arrangement portion 128 is connected to the end of the third protrusion 112 in the direction of arrow B1. The outer arrangement portion 128 and the first protrusion 88 face each other while being spaced apart from each other. The outer arrangement portion 128 has an outer seal arrangement surface 132 on which the second communication hole seal portion 66e is arranged. The outer seal arrangement surface 132 faces the resin frame 30 (in the direction of arrow A2). The second communication hole seal portion 66e is arranged to straddle the tunnel 76a in a direction (in the direction of arrow C) that intersects the flow direction of the coolant flowing through the interior of the tunnel 76a (communication passage 82).

[0059] The outer seal arrangement surface 132 is located in the opposite direction (indicated by arrow A1) from the resin frame 30 relative to the third end surface 124. The outer seal arrangement surface 132 is located outward (indicated by arrow B1) from the first seal arrangement surface 110. The outer seal arrangement surface 132 is formed flat and is flush with the second surface 24a of the second metal separator 24.

[0060] The inner-arrangement portion 130 is connected to the end of the third protrusion 112 in the direction of arrow B2. The inner-arrangement portion 130 and the second protrusion 90 face each other while being spaced apart from each other. The inner-arrangement portion 130 has an inner seal arrangement surface 134 on which the second flow path seal portion 68 is arranged. The second flow path seal portion 68 is arranged so as to straddle the tunnel 76a in a direction (direction of arrow C) that intersects with the flow direction of the cooling medium circulating inside the tunnel 76a (communicating passage 82).

[0061] The inner seal arrangement surface 134 faces the resin frame 30 (in the direction of arrow A2). The inner seal arrangement surface 134 is located in the opposite direction (in the direction of arrow A1) from the resin frame 30 relative to the third end surface 124. The inner seal arrangement surface 134 is located more inward than the first seal arrangement surface 110. The inner seal arrangement surface 134 is flush with the second surface 24a of the second metal separator 24. The first seal arrangement surface 110 and the second seal arrangement surface 126 (the outer seal arrangement surface 132 and the inner seal arrangement surface 134) are offset in the flow direction (in the direction of arrow B) of the coolant flowing through the interior of the tunnel 76a (the communicating passage 82).

[0062] 2 and 3, the coolant outlet 74 has a plurality of tunnels 76b. The tunnels 76b of the coolant outlet 74 are configured similarly to the tunnels 76a of the coolant inlet 72. In the tunnels 76b of the coolant outlet 74, the same components as those of the tunnels 76a of the coolant inlet 72 are given the same reference numerals, and detailed description thereof will be omitted. The same applies to the fuel gas inlet 44, the fuel gas outlet 46, the oxidant gas inlet 60, and the oxidant gas outlet 62, which will be described later.

[0063] In the tunnel 76b of the coolant outlet portion 74, the first communication hole seal portion 50f and the first flow path seal portion 52 are arranged on the first seal arrangement surface 110 (see FIG. 2). In addition, in the tunnel 76b, the second communication hole seal portion 66f is arranged on the outer seal arrangement surface 132, and the second flow path seal portion 68 is arranged on the inner seal arrangement surface 134 (see FIG. 3).

[0064] The fuel gas introduction section 44 has multiple tunnels 140a. As shown in Fig. 2, in the tunnel 140a of the fuel gas introduction section 44, a first communication hole seal portion 50a is arranged on the first seal arrangement surface 110. An opening 142 is formed in the second protrusion 90 of the tunnel 140a, allowing communication between the communication passage 82 of the tunnel 140a and the first gas flow path 38. In the tunnel 140a, a second communication hole seal portion 66a is arranged on the second seal arrangement surface 126, which is located outward from the third protrusion 112 (see Fig. 3).

[0065] The fuel gas outlet section 46 has multiple tunnels 140b. The tunnels 140b of the fuel gas outlet section 46 are configured similarly to the tunnels 140a of the fuel gas introduction section 44. In the tunnels 140b of the fuel gas outlet section 46, the first communication hole seal portions 50b are arranged on the first seal arrangement surface 110. In addition, in the tunnels 140b, the second communication hole seal portions 66b are arranged on the second seal arrangement surface 126, which is positioned outward of the third protrusion 112 (see FIG. 3).

[0066] 2 and 3, the oxidant gas introduction section 60 has multiple tunnels 144a. In each tunnel 144a of the oxidant gas introduction section 60, a first tunnel wall 78 is provided in the second metal separator 24, and a second tunnel wall 80 is provided in the first metal separator 22. As shown in FIG. 3, in each tunnel 144a, a second communication hole seal 66c is provided on the first seal arrangement surface 110. An opening 146 is formed in the second protrusion 90 of the tunnel 144a, allowing communication between the communication passage 82 of the tunnel 144a and the second gas flow path 54. In each tunnel 144a, a first communication hole seal 50c is provided on the second seal arrangement surface 126, which is located outward from the third protrusion 112 (see FIG. 2).

[0067] The oxidant gas outlet 62 has a plurality of tunnels 144b. The tunnels 144b of the oxidant gas outlet 62 are configured similarly to the tunnels 144a of the oxidant gas introduction section 60. In the tunnels 144b of the oxidant gas outlet 62, the second communication-hole seal portion 66d is arranged on the first seal arrangement surface 110. In the tunnel 144b, the first communication-hole seal portion 50d is arranged on the second seal arrangement surface 126, which is positioned outward from the third protrusion 112 (see FIG. 2).

[0068] The present invention is not limited to the above-described configuration. In the tunnels 76a, 76b, 140a, 140b, 144a, and 144b, the first seal arrangement surface 110 may be located closer to the resin frame 30 than the first surface 22a of the first metal separator 22. Also, in the tunnels 76a, 76b, 140a, 140b, 144a, and 144b, the second seal arrangement surface 126 may be located closer to the resin frame 30 than the second surface 24a of the second metal separator 24. The power generation cell 10 may be configured so that oxidant gas flows through the first gas flow path 38 and fuel gas flows through the second gas flow path 54.

[0069] The following additional notes are further disclosed regarding the above embodiment.

[0070] (Appendix 1) A power generation cell (10) of the present disclosure includes a resin-framed membrane electrode assembly (20) having a membrane electrode assembly (28) formed by arranging electrodes (34, 36) on both sides of an electrolyte membrane (32), a resin frame portion (30) protruding outward from the outer periphery of the membrane electrode assembly and surrounding the membrane electrode assembly, metal separators (22, 24) arranged on both sides of the resin-framed membrane electrode assembly, and elastically deformable resin sealing members (48, 64) arranged between the resin frame portions and the metal separators, the metal separators having fluid communication holes (14a, 14b, 16a, 16b, 18a, 18b) for flowing a fluid such as an oxidant gas, a fuel gas, or a cooling medium in a thickness direction of the metal separators, and a resin sealing member (48, 64) for allowing the fluid to flow through the metal separators. a power generation cell provided with a fluid flow path (38, 54, 70) that allows fluid to flow in a plane direction of the metal separator, and a tunnel (76a, 76b, 140a, 140b, 144a, 144b) that connects the fluid flow path to each other, wherein the resin seal member is arranged to straddle the tunnel in a direction intersecting the flow direction of the fluid flowing through the interior (82) of the tunnel, and the tunnel has a convex portion (88, 90, 112) that protrudes from the metal separator toward the resin frame portion, and an arrangement portion (92, 114) that includes a seal arrangement surface (110, 126) on which the resin seal member is arranged, and the seal arrangement surface is located in the opposite direction from the resin frame portion relative to an end face (100, 108, 124) in the protruding direction of the convex portion.

[0071] This configuration can reduce the step (the dimension in the thickness direction of the metal separator) between the surface of the metal separator facing the resin frame and the seal placement surface. Alternatively, it can eliminate the step between the surface of the metal separator and the seal placement surface. This prevents excessive sealing surface pressure from acting on the portion of the resin seal member that overlaps with the tunnel when viewed from the thickness direction of the metal separator when a clamping load is applied to the power generation cell. This eliminates the need to form the resin seal member into a complex shape that corresponds to the shape of the convex portion of the tunnel. This makes it possible to effectively prevent fluid leakage while keeping manufacturing costs down.

[0072] (Appendix 2) In the power generation cell described in Appendix 1, the resin seal member includes a first resin seal member (48) arranged on a first seal arrangement surface (110) that is the seal arrangement surface of one of the metal separators, and a second resin seal member (64) arranged on a second seal arrangement surface (126) that is the seal arrangement surface of the other of the metal separators, and the first seal arrangement surface and the second seal arrangement surface may be offset in the flow direction so as not to overlap each other when viewed from the thickness direction.

[0073] With this configuration, the first resin seal member and the second resin seal member do not overlap at the tunnel position when viewed in the thickness direction of the metal separator, which allows the size of the power generating cell in the thickness direction of the metal separator to be reduced.

[0074] (Appendix 3) In the power generation cell described in Appendix 2, the first resin seal member includes a first communication hole seal portion (50) that surrounds the fluid communication hole and a first flow path seal portion (52) that surrounds the fluid flow path of the one of the metal separators, the second resin seal member includes a second communication hole seal portion (66) that surrounds the fluid communication hole and a second flow path seal portion (68) that surrounds the fluid flow path of the other metal separator, the second seal arrangement surface has an outer seal arrangement surface (132) that is located outward from the first seal arrangement surface and an inner seal arrangement surface (134) that is located inward from the first seal arrangement surface, and the second communication hole seal portion may be arranged on the outer seal arrangement surface, and the second flow path seal portion may be arranged on the inner seal arrangement surface.

[0075] With this configuration, the fluid flow path and fluid communication hole of one metal separator can be doubly sealed by the first flow path seal portion and the first communication hole seal portion, and the fluid flow path and fluid communication hole of the other metal separator can be doubly sealed by the second flow path seal portion and the second communication hole seal portion.

[0076] (Appendix 4) In the power generating cell according to any one of Supplementary Notes 1 to 3, the seal placement surface may be formed flat and may be flush with the surface (22a, 24a) of the metal separator facing the resin frame portion.

[0077] With this configuration, no step is formed between the surface of the metal separator facing the resin frame portion and the seal placement surface, so the surface pressure of the resin seal member can be made approximately uniform when a clamping load is applied to the power generation cell.

[0078] (Appendix 5) The fuel cell stack (12) of the present disclosure is formed by stacking a plurality of power generating cells according to any one of Supplementary Notes 1 to 4.

[0079] Although the present disclosure has been described in detail, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible in these embodiments without departing from the gist of the present disclosure or the spirit of the present disclosure derived from the content of the claims and their equivalents. These embodiments can also be implemented in combination. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these. The same applies when numerical values ​​or mathematical expressions are used in the description of the above-described embodiments. [Explanation of symbols]

[0080] 10...power generating cell 12...fuel cell stack 14a...oxidant gas supply passage 14b...oxidant gas discharge passage 16a...fuel gas supply passage 16b...fuel gas discharge passage 18a...Cooling medium supply communication hole 18b...Cooling medium discharge communication hole 20... Resin-framed membrane electrode assembly 22... First metal separator 22a...first surface 24...second metal separator 24a...Second surface 28...Membrane electrode assembly 30...resin frame portion 32...electrolyte membrane 34...First electrode 36...Second electrode 38...first gas flow path 48...first resin seal member 50...first communication hole seal portion 52...first flow path seal portion 54... Second gas flow path 64... Second resin seal member 66...Second communication hole seal portion 68...Second flow path seal portion 70...coolant flow path 76a, 76b, 140a, 140b, 144a, 144b... Tunnels 82...Communicating passage 88...First protrusion 90... Second protrusion 92... First arrangement portion 100...First end face 108...Second end face 110...first seal arrangement surface 112...third protrusion 114...Second arrangement part 124...Third end surface 126... Second seal arrangement surface 132... Outer seal arrangement surface 134...Inner seal placement surface

Claims

1. a resin-framed membrane electrode assembly including a membrane electrode assembly formed by disposing electrodes on both sides of an electrolyte membrane, and a resin frame portion that protrudes outward from the outer periphery of the membrane electrode assembly and surrounds the membrane electrode assembly; metal separators disposed on both sides of the resin-framed membrane electrode assembly; an elastically deformable resin sealing member disposed between the resin frame and the metal separator; Equipped with The metal separator includes: a fluid communication hole through which a fluid such as an oxidant gas, a fuel gas, or a cooling medium flows in a thickness direction of the metal separator; a fluid flow path that allows the fluid to flow in a surface direction of the metal separator; a tunnel that connects the fluid communication hole and the fluid flow path to each other; A power generating cell provided with the resin seal member is disposed so as to straddle the tunnel in a direction intersecting a flow direction of the fluid flowing inside the tunnel, One of the metal separators is provided with a first tunnel wall portion, The other metal separator is provided with a second tunnel wall portion, The first tunnel wall portion is a first protrusion protruding from the one metal separator toward the resin frame; a second protrusion protruding from the one metal separator toward the resin frame and spaced apart from the first protrusion; a placement portion including a first seal placement surface located between the first convex portion and the second convex portion and on which the resin seal member is placed; and a third protrusion that forms the second tunnel wall portion is provided at a position of the other metal separator that faces the placement portion, an internal space of the first convex portion, an internal space of the third convex portion, and an internal space of the second convex portion communicate with each other to form a flow path inside the tunnel; The power generating cell, wherein the first seal placement surface is located on the opposite side from the resin frame portion relative to the end face in the protruding direction of the first convex portion.

2. The power generating cell according to claim 1, The resin sealing member is a first resin seal member disposed on the first seal placement surface; a second resin seal member disposed on a second seal placement surface of the other metal separator; and The power generation cell, wherein the first seal arrangement surface and the second seal arrangement surface are offset in the flow direction so as not to overlap each other when viewed in the thickness direction.

3. The power generating cell according to claim 2, The first resin seal member is a first communication hole seal portion surrounding the fluid communication hole; a first flow path seal portion surrounding the fluid flow path of the one of the metal separators; Including, The second resin seal member is a second communication hole seal portion surrounding the fluid communication hole; a second flow path seal portion surrounding the fluid flow path of the other metal separator; Including, The second seal placement surface is an outer seal placement surface located outward from the first seal placement surface; an inner seal placement surface located inward from the first seal placement surface; and the second communication hole seal portion is disposed on the outer seal arrangement surface, The second flow path seal portion is disposed on the inner seal arrangement surface of the power generation cell.

4. The power generating cell according to claim 1, The first seal placement surface is formed flat and is flush with the surface of the one metal separator that faces the resin frame portion.

5. A fuel cell stack comprising a plurality of power generating cells according to claim 1 stacked together.

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