JP2013201086A - Fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell that, with a simple configuration, allows produced water, which is likely to be accumulated on a lower side of an electrode surface in the direction of gravitational force, to be easily and reliably drained from the electrode surface.SOLUTION: A fuel cell 10 includes power generation units 12. Each power generation unit 12 has a first metal separator 14, a first membrane electrode assembly 16a, a second metal separator 18, a second membrane electrode assembly 16b, and a third metal separator 20. A first oxidant gas passage 26 is formed on a surface 14a of the first metal separator 14. At a lower end of the first oxidant gas passage 26 in the direction of gravitational force, a first cathode drainage channel 32 is provided for draining produced water downward in the direction of gravitational force. The first cathode drainage channel 32 is defined by uneven portions 34a and 34b that are alternately formed on the surface 14a, and a surface 14b, of the first metal separator 14.

Description

  In the present invention, an electrolyte membrane / electrode structure provided with a pair of electrodes on both sides of an electrolyte membrane and a metal separator are laminated in a horizontal direction, and the electrode surface is in a vertical posture along the direction of gravity and in the horizontal direction. In particular, the present invention relates to a fuel cell having a long horizontally long shape and provided with a reaction gas flow path through which a reaction gas that is an oxidant gas or a fuel gas flows along the longitudinal direction of the electrode surface.

  For example, in a polymer electrolyte fuel cell, an electrolyte membrane / electrode structure (MEA) provided with an anode electrode and a cathode electrode on both sides of an electrolyte membrane made of a polymer ion exchange membrane is sandwiched between a pair of separators. Yes. In general, a plurality of fuel cells are stacked to form a fuel cell stack, and are used as an in-vehicle fuel cell system by being incorporated in a fuel cell vehicle for in-vehicle use as well as for stationary use.

  In a fuel cell, a fuel gas flow path (hereinafter also referred to as a reaction gas flow path) for flowing a fuel gas to the anode electrode and an oxidant gas flow path for flowing an oxidant gas to the cathode electrode in the plane of the separator (Hereinafter also referred to as a reaction gas channel). Further, for each power generation cell or for each of the plurality of power generation cells, a cooling medium flow path for flowing a cooling medium is provided along the electrode surface direction between adjacent separators.

  In this type of fuel cell, it is necessary to moisturize the electrolyte membrane in order to ensure good ion conductivity. For this reason, a method is employed in which an oxidizing gas (for example, air) or a fuel gas (for example, hydrogen gas), which is a reactive gas, is humidified and supplied to the fuel cell.

  At this time, moisture for humidification may be liquefied without being absorbed by the electrolyte membrane and stay in the reaction gas flow path. On the other hand, in the fuel cell, generated water is generated at the cathode electrode by a power generation reaction, and the generated water is back-diffused through the electrolyte membrane in the anode electrode. For this reason, moisture tends to condense and stay on the lower end side in the gravity direction of the reaction gas channel due to the action of gravity, and flooding due to condensed water may occur.

  Therefore, for example, a polymer electrolyte fuel cell disclosed in Patent Document 1 is known as a fuel cell that aims to efficiently drain gas while discharging gas effectively. As shown in FIG. 17, the fuel cell includes a frame 1, and a cell 2 and a cathode-side flow path substrate 3 are fitted on one surface side of the frame 1, and the frame body An anode side flow path substrate 4 is fitted on the other surface side of 1.

  The cell 2 is configured by arranging a cathode 2b and an anode 2c on a solid polymer electrolyte 2a. A plurality of cathode-side channels 3 a are formed on the cathode-side channel substrate 3, while a plurality of anode-side channels 4 a are formed on the anode-side channel substrate 4.

  In the upstream portion of the frame 1, a pair of water introduction manifold holes 5 a, a groove hole 5 b that communicates the water introduction manifold hole 5 a with the anode side flow path 4 a, a pair of fuel gas introduction manifold holes 6 a, and the fuel A groove 6b is formed to communicate the gas introduction manifold hole 6a with the anode-side flow path 4a. In the downstream portion of the frame 1, a pair of fuel gas outlet manifold holes 7a, a groove hole 7b communicating the fuel gas outlet manifold hole 7a with the anode-side flow path 4a, a pair of water outlet manifold holes 8a, A groove 8b is formed to communicate the water lead-out manifold hole 8a with the anode-side channel 4a.

  The unreacted fuel gas that has passed through the anode side channel 4a is discharged from the groove hole 7b through the fuel gas outlet manifold hole 7a to the outside of the battery, and the water that has passed through the anode side channel 4a is The water is discharged out of the battery from the groove hole 8b through the water outlet manifold hole 8a.

Japanese Patent No. 3123992

  However, in the above-mentioned Patent Document 1, the frame 1 is considerably elongated along the fuel gas flow direction. For this reason, if the cathode-side flow path 3a is arranged so as to be horizontally oriented, the height dimension of the entire fuel cell becomes large, and the mounting space when the fuel cell is mounted on a vehicle is limited. There is.

  Moreover, water generated by power generation is generated in the cathode-side flow path 3a. The generated water may move downward in the direction of gravity and stay there, causing a problem of insufficient supply of the oxidant gas.

  The present invention solves this type of problem, and can easily and reliably discharge generated water that tends to stay below the electrode surface in the direction of gravity in the electrode surface with a simple configuration. The purpose is to provide.

  In the present invention, an electrolyte membrane / electrode structure provided with a pair of electrodes on both sides of an electrolyte membrane and a metal separator are laminated in a horizontal direction, and the electrode surface is in a vertical posture along the direction of gravity and in the horizontal direction. The present invention relates to a fuel cell having a long horizontally long shape and provided with a reaction gas channel through which a reaction gas, which is an oxidant gas or a fuel gas, flows along the longitudinal direction of the electrode surface.

  In this fuel cell, a drainage passage for discharging generated water from the reaction gas channel downward in the direction of gravity is provided at the lower end in the gravity direction of the reaction gas channel, and the drainage channel is connected to the reaction of the metal separator. It is comprised by the uneven | corrugated shaped part alternately formed in the surface on the gas flow path side, and the surface opposite to this surface.

  Further, in this fuel cell, a reaction gas outlet communication hole communicating with the reaction gas channel and penetrating in the stacking direction is provided at the lower end of the metal separator in the horizontal direction, and the drainage channel is provided below the uneven portion. The drainage flow path preferably extends in the longitudinal direction of the metal separator and communicates with the reaction gas outlet communication hole.

  Further, in this fuel cell, it is preferable that the electrolyte membrane / electrode structure is provided with a resin frame member on the outer peripheral portion, and the drainage channel is formed between the resin frame member and the metal separator.

  According to the present invention, when the reaction gas flows along the electrode surface that is long in the horizontal direction, water is generated by the reaction, and this water tends to stay below the electrode surface in the direction of gravity. At this time, a drainage passage is provided below the electrode surface in the direction of gravity, and water that has moved below the electrode surface in the direction of gravity is discharged from the drainage passage to the outside of the electrode surface.

  Furthermore, the drainage passage is constituted by a concavo-convex shape portion formed alternately on the surface of the metal separator on the side of the reactive gas flow channel and on the surface opposite to the surface. For this reason, it is only necessary to press the metal separator, and it is possible to easily and surely discharge the generated water that tends to stay below the electrode surface in the direction of gravity in a simple configuration. Therefore, the fuel cell can satisfactorily maintain the optimum power generation environment.

It is a principal part disassembled perspective explanatory drawing of the electric power generation unit which comprises the fuel cell which concerns on the 1st Embodiment of this invention. FIG. 2 is a cross-sectional explanatory view taken along line II-II in FIG. 1 of the power generation unit. FIG. 3 is a cross-sectional explanatory view taken along line III-III in FIG. 1 of the power generation unit. FIG. 4 is a cross-sectional explanatory view taken along line IV-IV in FIG. 1 of the power generation unit. It is front explanatory drawing of the 1st metal separator which comprises the said electric power generation unit. FIG. 6 is a cross-sectional view of the first metal separator taken along line VI-VI in FIG. 5. It is explanatory drawing of one surface of the 2nd metal separator which comprises the said electric power generation unit. It is explanatory drawing of the other surface of the said 2nd metal separator. It is explanatory drawing of one surface of the 3rd metal separator which comprises the said electric power generation unit. It is explanatory drawing of the other surface of the said 3rd metal separator. It is explanatory drawing of one surface of the 1st electrolyte membrane and electrode structure which comprises the said electric power generation unit. It is explanatory drawing of the other surface of the said 1st electrolyte membrane and electrode structure. It is explanatory drawing of one surface of the 2nd electrolyte membrane and electrode structure which comprises the said electric power generation unit. It is explanatory drawing of the other surface of the said 2nd electrolyte membrane and electrode structure. It is a principal part disassembled perspective explanatory drawing of the electric power generation unit which comprises the fuel cell which concerns on the 2nd Embodiment of this invention. It is the XVI-XVI sectional view taken on the line of FIG. 15 of the said electric power generation unit. 2 is an exploded perspective view of a fuel cell disclosed in Patent Document 1. FIG.

  As shown in FIGS. 1 to 4, the fuel cell 10 according to the first embodiment of the present invention includes a power generation unit 12, and the plurality of power generation units 12 are arranged in a horizontal direction (arrow A direction) or a vertical direction (arrows). Are laminated together along the C direction). The power generation unit 12 includes a first metal separator 14, a first electrolyte membrane / electrode structure 16 a, a second metal separator 18, a second electrolyte membrane / electrode structure 16 b, and a third metal separator 20. The first metal separator 14, the first electrolyte membrane / electrode structure 16 a, the second metal separator 18, the second electrolyte membrane / electrode structure 16 b, and the third metal separator 20 are stacked along the horizontal direction, The surface is in a vertical posture along the direction of gravity and has a horizontally long shape that is long in the horizontal direction.

  The first metal separator 14, the second metal separator 18, and the third metal separator 20 are, for example, a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, or a horizontally long metal whose surface has been subjected to anticorrosion treatment. Consists of plates. The first metal separator 14, the second metal separator 18, and the third metal separator 20 have a rectangular planar shape, and are formed into a concavo-convex shape by pressing a metal thin plate into a wave shape.

  As shown in FIG. 1, specifically, the length of the first metal separator 14, the second metal separator 18, and the third metal separator 20 is arranged at one end edge of the power generation unit 12 in the long side direction (arrow B direction). One end edge in the side direction communicates with each other in the direction of arrow A, and an oxidant gas inlet communication hole 22a for supplying an oxidant gas, for example, an oxygen-containing gas, and a fuel gas, for example, a hydrogen-containing gas. A fuel gas outlet communication hole 24b for discharging is provided.

  The other end edge of the power generation unit 12 in the long side direction (arrow B direction) communicates with each other in the arrow A direction, and discharges the fuel gas inlet communication hole 24a for supplying fuel gas and the oxidant gas. For this purpose, an oxidant gas outlet communication hole 22b is provided.

  A pair of cooling media for supplying a cooling medium in communication with each other in the direction of arrow A to one end of the power generation unit 12 in the short side direction (arrow C direction) on the oxidant gas inlet communication hole 22a side. An inlet communication hole 25a is provided. A pair of cooling medium outlet communication holes 25b for discharging the cooling medium is provided on the other end on the short side direction of the power generation unit 12 on the fuel gas inlet communication hole 24a side.

  As shown in FIG. 5, the surface 14a of the first metal separator 14 facing the first electrolyte membrane / electrode structure 16a is connected to the oxidant gas inlet communication hole 22a and the oxidant gas outlet communication hole 22b. An oxidant gas flow path 26 is formed.

  The first oxidant gas channel 26 has a plurality of wave-like channel grooves (or linear channel grooves) 26 a extending in the direction of arrow B, and the vicinity of the inlet and the outlet of the first oxidant gas channel 26. In the vicinity, an inlet embossed portion 28a and an outlet embossed portion 28b each having a plurality of embosses are provided.

  A plurality of inlet connection grooves 30a constituting a bridge portion are formed between the inlet embossed portion 28a and the oxidizing gas inlet communication hole 22a, while the outlet embossed portion 28b and the oxidizing gas outlet communication hole 22b A plurality of outlet connection grooves 30b constituting the bridge portion are formed therebetween.

  A first cathode drain passage 32 is provided at the lower end in the gravity direction of the first oxidant gas passage 26 to discharge generated water downward from the first oxidant gas passage 26 in the direction of gravity. The first cathode drainage passage 32 is configured by uneven portions 34a and 34b that are alternately formed on the surface 14a of the first metal separator 14 and the surface 14b opposite to the surface 14a. The concave and convex portions 34 a and 34 b are press-molded on the first metal separator 14.

  The concavo-convex shape portion 34a has a protrusion shape (dent shape from the back surface) that bulges to the surface 14a side, while the concavo-convex shape portion 34b has a protrusion shape (dent shape from the back surface) bulges to the surface 14b side. (See FIG. 6). The lengths (dimensions in the direction of arrow C) of the concavo-convex portions 34a and 34b periodically change in accordance with the shape of the wavy flow channel groove 26a.

  As shown in FIG. 2, the concavo-convex portion 34 a abuts on a first resin frame member 80 described later and partially closes the first cathode drain passage 32. As shown in FIG. 5, a drainage flow channel 36 extending in the direction of arrow B is provided below the first cathode drainage passage 32. The drainage channel 36 is set to a pressure loss larger than the pressure loss per one of the first oxidant gas channels 26 and communicates with the oxidant gas outlet communication hole 22b.

  As shown in FIG. 1, a cooling medium flow path 38 that connects the cooling medium inlet communication hole 25 a and the cooling medium outlet communication hole 25 b is formed on the surface 14 b of the first metal separator 14. The cooling medium channel 38 is formed by overlapping the back surface shape of the first oxidant gas channel 26 and the back surface shape of the second fuel gas channel 58 described later.

  As shown in FIG. 7, the first fuel gas that communicates the fuel gas inlet communication hole 24a and the fuel gas outlet communication hole 24b to the surface 18a of the second metal separator 18 facing the first electrolyte membrane / electrode structure 16a. A flow path 40 is formed. The first fuel gas channel 40 has a plurality of wave-like channel grooves (or linear channel grooves) 40a extending in the direction of arrow B. A plurality of supply holes 42a are formed in the vicinity of the fuel gas inlet communication hole 24a, and a plurality of discharge holes 42b are formed in the vicinity of the fuel gas outlet communication hole 24b.

  A first anode drainage passage 44 for discharging generated water (back diffusion water) from the first fuel gas passage 40 downward in the gravity direction is provided at the lower end of the first fuel gas passage 40 in the gravity direction. The first anode drainage passage 44 is constituted by concave and convex portions 46a and 46b that are alternately formed on the surface 18a of the second metal separator 18 and the surface 18b opposite to the surface 18a.

  The concavo-convex shape portion 46a has a protrusion shape bulging toward the surface 18a (a concave shape from the back surface), while the concavo-convex shape portion 46b has a protrusion shape bulging toward the surface 18b (a dent shape from the back surface). . The lengths (dimensions in the direction of arrow C) of the concavo-convex shape portions 46a and 46b periodically change in accordance with the shape of the wave-like channel groove portion 40a.

  As shown in FIG. 2, the concavo-convex portion 46 a abuts on an anode electrode 78 of a first electrolyte membrane / electrode structure 16 a described later to partially close the first anode drainage passage 44. As shown in FIG. 7, a drainage flow path 48 extending in the direction of arrow B is provided below the first anode drainage passage 44. The drainage channel 48 is set to a pressure loss larger than the pressure loss per one of the first fuel gas channels 40, and communicates with the discharge hole 42b.

  As shown in FIG. 8, the surface 18b of the second metal separator 18 facing the second electrolyte membrane / electrode structure 16b communicates with the oxidant gas inlet communication hole 22a and the oxidant gas outlet communication hole 22b. An oxidant gas flow path 50 is formed. The second oxidizing gas channel 50 has a plurality of wave-like channel grooves (or linear channel grooves) 50a extending in the direction of arrow B. A plurality of inlet connection grooves 52a are formed in the vicinity of the oxidant gas inlet communication hole 22a, while a plurality of outlet connection grooves 52b are formed in the vicinity of the oxidant gas outlet communication hole 22b.

  A second cathode drain passage 54 for discharging generated water from the second oxidant gas flow channel 50 downward in the gravity direction is provided at the lower end of the second oxidant gas flow channel 50 in the gravity direction. The second cathode drainage passage 54 is configured by uneven portions 46 a and 46 b which are the back surface shape of the first anode drainage passage 44. As shown in FIG. 2, the concavo-convex portion 46 b abuts on a second resin frame member 82 described later and partially closes the second cathode drain passage 54. As shown in FIG. 8, a drainage flow path 56 extending in the direction of arrow B is provided below the second cathode drainage passage 54. The drainage flow path 56 communicates with the oxidant gas outlet communication hole 22b.

  As shown in FIG. 9, the second fuel gas flow communicating with the fuel gas inlet communication hole 24a and the fuel gas outlet communication hole 24b is formed on the surface 20a of the third metal separator 20 facing the second electrolyte membrane / electrode structure 16b. A path 58 is formed. The second fuel gas channel 58 has a plurality of wave-like channel grooves (or linear channel grooves) 58a extending in the direction of arrow B.

  A plurality of supply holes 60a are formed in the vicinity of the fuel gas inlet communication hole 24a, and a plurality of discharge holes 60b are formed in the vicinity of the fuel gas outlet communication hole 24b. As shown in FIGS. 1 and 3, the supply hole 60 a is disposed on the inner side (fuel gas flow path side) of the second metal separator 18 than the supply hole 42 a, while the discharge hole 60 b It arrange | positions inside the discharge hole part 42b of the metal separator 18 (fuel gas flow path side).

  As shown in FIG. 9, at the lower end in the gravity direction of the second fuel gas passage 58, a second anode drain for discharging generated water (back diffusion water) downward from the second fuel gas passage 58 in the gravity direction. A passage 62 is provided. The second anode drainage passage 62 is composed of the concave and convex portions 64a and 64b that are alternately formed on the surface 20a of the third metal separator 20 and the surface 20b opposite to the surface 20a.

  The concavo-convex shape portion 64a has a protrusion shape (dent shape from the back surface) that bulges to the surface 20a side, while the concavo-convex shape portion 64b has a protrusion shape (dent shape from the back surface) bulges to the surface 20b side. . The lengths (dimensions in the direction of arrow C) of the concavo-convex shape portions 64a and 64b periodically change in accordance with the shape of the wavy flow channel groove portion 58a.

  As shown in FIG. 2, the concavo-convex shape portion 64a abuts on an anode electrode 78 of a second electrolyte membrane / electrode structure 16b described later to partially close the second anode drainage passage 62. As shown in FIG. 9, a drainage channel 66 extending in the direction of arrow B is provided below the second anode drainage passage 62. The drainage channel 66 is set to a pressure loss larger than the pressure loss per one of the second fuel gas channels 58, and communicates with the discharge hole 60b.

  As shown in FIG. 10, a part of the cooling medium flow path 38 that is the back surface shape of the second fuel gas flow path 58 is formed on the surface 20 b of the third metal separator 20. A cooling medium flow path 38 is integrally provided on the surface 20 b of the third metal separator 20 by laminating the surface 14 b of the first metal separator 14 adjacent to the third metal separator 20. At the lower end in the gravity direction of the cooling medium flow path 38, concave and convex portions 64a and 64b that are the back surface shape of the second anode drainage passage 62 are provided.

  As shown in FIG. 1, the first seal member 68 is integrally formed on the surfaces 14 a and 14 b of the first metal separator 14 around the outer peripheral edge of the first metal separator 14. A second seal member 70 is integrally formed around the outer peripheral edge of the second metal separator 18 on the surfaces 18a and 18b of the second metal separator 18, and the surfaces 20a and 20b of the third metal separator 20 are integrally formed. The third seal member 72 is integrally formed around the outer peripheral edge of the third metal separator 20.

  Examples of the first seal member 68, the second seal member 70, and the third seal member 72 include EPDM, NBR, fluororubber, silicone rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroprene, or acrylic rubber. A sealing material having elasticity such as a sealing material, a cushioning material, or a packing material is used.

  As shown in FIG. 5, the first seal member 68 includes an oxidant gas inlet communication hole 22 a and an oxidant gas outlet communication hole 22 b on the surface 14 a of the first metal separator 14, and the first oxidant gas flow path 26. A first convex seal portion 68a communicating with the outer periphery of the first convex seal portion 68a. As shown in FIG. 1, the first seal member 68 communicates the outer periphery of the cooling medium inlet communication hole 25 a, the cooling medium outlet communication hole 25 b, and the cooling medium flow path 38 on the surface 14 b of the first metal separator 14. It has two convex seal portions 68b.

  As shown in FIG. 7, the second seal member 70 surrounds the supply hole portion 42 a and the discharge hole portion 42 b and the first fuel gas flow path 40 on the surface 18 a of the second metal separator 18 and communicates them. The first convex seal portion 70a is provided.

  As shown in FIG. 8, the second seal member 70 communicates the outer periphery of the oxidant gas inlet communication hole 22 a and the oxidant gas outlet communication hole 22 b with the second oxidant gas flow path 50 on the surface 18 b. It has two convex seal parts 70b.

  As shown in FIG. 9, the third seal member 72 surrounds the supply hole portion 60 a and the discharge hole portion 60 b and the second fuel gas channel 58 on the surface 20 a of the third metal separator 20, and communicates these. A first convex seal portion 72a.

  As shown in FIG. 10, the third seal member 72 communicates the outer periphery of the cooling medium inlet communication hole 25 a, the cooling medium outlet communication hole 25 b, and the cooling medium flow path 38 on the surface 20 b of the third metal separator 20. Two convex seal portions 72b are provided.

  As shown in FIG. 2, the first electrolyte membrane / electrode structure 16a and the second electrolyte membrane / electrode structure 16b include, for example, a solid polymer electrolyte membrane 74 in which a perfluorosulfonic acid thin film is impregnated with water, A cathode electrode 76 and an anode electrode 78 sandwiching the solid polymer electrolyte membrane 74 are provided. The cathode electrode 76 constitutes a stepped MEA having a surface area smaller than that of the anode electrode 78 and the solid polymer electrolyte membrane 74. The cathode electrode 76, the anode electrode 78, and the solid polymer electrolyte membrane 74 may be set to the same surface area, and the anode electrode 78 is smaller than the surface area of the cathode electrode 76 and the solid polymer electrolyte membrane 74. It may have a surface area.

  The cathode electrode 76 and the anode electrode 78 have a gas diffusion layer (not shown) made of carbon paper or the like, and porous carbon particles having a platinum alloy supported on the surface are uniformly applied to the surface of the gas diffusion layer. And an electrode catalyst layer (not shown) to be formed. The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 74.

  The first electrolyte membrane / electrode structure 16a is located outside the terminal portion of the cathode electrode 76, and the first resin frame member 80 is integrally formed on the outer peripheral edge of the solid polymer electrolyte membrane 74 by, for example, injection molding or the like. Is done. The second electrolyte membrane / electrode structure 16b is located outside the terminal portion of the cathode electrode 76, and the second resin frame member 82 is integrally formed on the outer peripheral edge of the solid polymer electrolyte membrane 74 by, for example, injection molding or the like. Is done. As a resin material constituting the first resin frame member 80 and the second resin frame member 82, for example, engineering plastics, super engineering plastics, etc. are adopted in addition to general-purpose plastics.

  As shown in FIGS. 11 and 12, the first resin frame member 80 bulges toward the oxidant gas inlet communication hole 22a and the oxidant gas outlet communication hole 22b at both ends in the longitudinal direction (arrow B direction). Protrusions 80a and 80b and projecting parts 80c and 80d that bulge toward the fuel gas inlet communication hole 24a and the fuel gas outlet communication hole 24b.

  The surface of the first resin frame member 80 on the cathode electrode 76 side is located between the oxidant gas inlet communication hole 22a and the inlet side of the first oxidant gas flow channel 26, as shown in FIG. A buffer portion 84 a is provided, and an outlet buffer portion 84 b is provided between the oxidant gas outlet communication hole 22 b and the outlet side of the first oxidant gas flow channel 26.

  As shown in FIG. 12, the surface of the first resin frame member 80 on the anode electrode 78 side is provided with an inlet buffer portion 86a located between the fuel gas inlet communication hole 24a and the first fuel gas flow path 40. In addition, an outlet buffer portion 86b is provided between the fuel gas outlet communication hole 24b and the first fuel gas flow path 40.

  As shown in FIGS. 13 and 14, the second resin frame member 82 provided in the second electrolyte membrane / electrode structure 16b includes an oxidant gas inlet communication hole 22a, an oxidant gas outlet communication hole 22b, and a fuel gas inlet communication. Projections 82a, 82b, 82c, and 82d that bulge toward the hole 24a and the fuel gas outlet communication hole 24b are provided.

  As shown in FIG. 13, the surface of the second resin frame member 82 on the cathode electrode 76 side is located between the oxidant gas inlet communication hole 22a and the second oxidant gas flow path 50, and an inlet buffer 88a. Is provided, and an outlet buffer portion 88b is formed between the oxidant gas outlet communication hole 22b and the second oxidant gas flow path 50.

  On the surface of the second resin frame member 82 on the anode electrode 78 side, as shown in FIG. 14, an inlet buffer portion 90a is provided between the fuel gas inlet communication hole 24a and the second fuel gas flow path 58. In addition, an outlet buffer portion 90b is provided between the fuel gas outlet communication hole 24b and the second fuel gas flow path 58.

  When the power generation units 12 are stacked on each other, a cooling medium flow path is provided between the first metal separator 14 constituting one power generation unit 12 and the third metal separator 20 constituting the other power generation unit 12. 38 is formed.

  The operation of the fuel cell 10 configured as described above will be described below.

  First, as shown in FIG. 1, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas inlet communication hole 22a, and a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet communication hole 24a. Further, a cooling medium such as pure water, ethylene glycol, or oil is supplied to the cooling medium inlet communication hole 25a.

  Therefore, as shown in FIG. 4, the oxidant gas is supplied from the oxidant gas inlet communication hole 22a to the first oxidant gas flow path 26 of the first metal separator 14 through the inlet buffer portion 84a. The oxidant gas is introduced into the second oxidant gas flow path 50 of the second metal separator 18 from the oxidant gas inlet communication hole 22a through the inlet buffer portion 88a.

  As shown in FIGS. 1, 5 and 8, the oxidant gas moves in the direction of arrow B (horizontal direction) along the first oxidant gas flow path 26, and the first electrolyte membrane / electrode structure 16a is moved. In addition to being supplied to the cathode electrode 76, it moves in the direction of arrow B along the second oxidant gas flow path 50, and is supplied to the cathode electrode 76 of the second electrolyte membrane / electrode structure 16b.

  On the other hand, as shown in FIG. 3, the fuel gas is supplied from the fuel gas inlet communication hole 24a to the inlet buffer part 86a through the supply hole part 42a. The fuel gas is supplied to the first fuel gas channel 40 of the second metal separator 18 through the inlet buffer portion 86a. The fuel gas is supplied from the fuel gas inlet communication hole 24a through the supply hole 60a to the inlet buffer 90a. The fuel gas is supplied to the second fuel gas channel 58 of the third metal separator 20 through the inlet buffer unit 90a.

  As shown in FIGS. 1, 7, and 9, the fuel gas moves in the direction of arrow B along the first fuel gas flow path 40 and is supplied to the anode electrode 78 of the first electrolyte membrane / electrode structure 16a. At the same time, it moves in the direction of arrow B along the second fuel gas flow path 58 and is supplied to the anode electrode 78 of the second electrolyte membrane / electrode structure 16b.

  Therefore, in the first electrolyte membrane / electrode structure 16a and the second electrolyte membrane / electrode structure 16b, the oxidizing gas supplied to each cathode electrode 76 and the fuel gas supplied to each anode electrode 78 are electrodes. Electricity is generated by being consumed by an electrochemical reaction in the catalyst layer.

  Next, the oxidant gas supplied to and consumed by the cathode electrodes 76 of the first electrolyte membrane / electrode structure 16a and the second electrolyte membrane / electrode structure 16b is communicated with the oxidant gas outlet from the outlet buffer portions 84b and 88b. It is discharged into the hole 22b (see FIG. 1).

  The fuel gas consumed by being supplied to the anode electrode 78 of the first electrolyte membrane / electrode structure 16a and the second electrolyte membrane / electrode structure 16b passes through the discharge holes 42b, 60b from the outlet buffer portions 86b, 90b. It is discharged into the fuel gas outlet communication hole 24b.

  On the other hand, the cooling medium supplied to the pair of left and right cooling medium inlet communication holes 25a is supplied to the cooling medium flow path 38 from each cooling medium inlet communication hole 25a, as shown in FIG. The cooling medium once flows in the direction of the arrow C and then moves in the direction of the arrow B to cool the first electrolyte membrane / electrode structure 16a and the second electrolyte membrane / electrode structure 16b. This cooling medium moves outward in the direction of arrow C, and is then discharged into the pair of cooling medium outlet communication holes 25b.

  As described above, when each power generation unit 12 in the fuel cell 10 generates power, generated water is generated in the first oxidant gas channel 26 and the second oxidant gas channel 50 by a power generation reaction. For example, the first oxidant gas flow path 26 is formed in a long length in the horizontal direction, and the generated water moves from the middle of the first oxidant gas flow path 26 in the downward direction of gravity to generate gravity on the power generation surface. It tends to stay in the lower direction.

  In this case, in the first embodiment, as shown in FIGS. 2 and 5, the surface 14 a of the first metal separator 14 has the first oxidant gas channel 26 at the lower end in the gravitational direction. A first cathode drain passage 32 for discharging the generated water from the gas flow path 26 downward in the direction of gravity is provided.

  For this reason, the generated water that has moved to the lower end side of the first oxidant gas flow path 26 flows into the drainage flow path 36 through the first cathode drainage path 32, and then the arrow along the drainage flow path 36. It moves in the B direction and is discharged to the oxidant gas outlet communication hole 22b.

  Further, the first cathode drainage passage 32 is constituted by concave and convex portions 34a and 34b alternately and integrally formed (press-molded) on the surface 14a of the first metal separator 14 and the surface 14b opposite to the surface 14a. .

  Therefore, in the first oxidant gas flow channel 26, it is possible to easily and surely discharge the generated water that tends to stay below the electrode surface in the gravity direction with a simple configuration. Thereby, the effect that the fuel cell 10 can maintain the optimal power generation environment satisfactorily is obtained. Further, in the second oxidant gas flow channel 50, the same effect as the first oxidant gas flow channel 26 is obtained.

  On the other hand, in the first fuel gas flow channel 40 and the second fuel gas flow channel 58, generated water obtained by reverse diffusion of the solid polymer electrolyte membrane 74 from the first oxidant gas flow channel 26 and the second oxidant gas flow channel 50 is provided. Is present. This generated water tends to move downward in the direction of gravity from the middle of the first fuel gas flow path 40 and the second fuel gas flow path 58 and stays below the electrode surface in the direction of gravity.

  Here, as shown in FIGS. 2 and 7, the generated water from the first fuel gas flow path 40 is gravity-induced to the surface 18 a of the second metal separator 18 at the lower end in the gravity direction of the first fuel gas flow path 40. A first anode drain passage 44 is provided for discharging downward in the direction.

  For this reason, the generated water that has moved to the lower end side of the first fuel gas channel 40 flows to the drainage channel 48 through the first anode drainage channel 44, and then the arrow B along the drainage channel 48. It moves in the direction and is discharged to the fuel gas outlet communication hole 24b.

  Further, the first anode drainage passage 44 is constituted by concave and convex portions 46a and 46b alternately and integrally formed (press-molded) on the surface 18a of the second metal separator 18 and the surface 18b opposite to the surface 18a. .

  Therefore, in the first fuel gas flow path 40, it is possible to easily and reliably discharge the generated water that tends to stay below the electrode surface in the gravity direction with a simple configuration. Thereby, the effect that the fuel cell 10 can maintain the optimal power generation environment satisfactorily is obtained. Further, in the second fuel gas channel 58, the same effect as that of the first fuel gas channel 40 is obtained.

  As shown in FIGS. 15 and 16, the fuel cell 120 according to the second embodiment of the present invention is configured by stacking a plurality of power generation units 122.

  The power generation unit 122 is configured by sandwiching the electrolyte membrane / electrode structure 16 between the first metal separator 14 and the second metal separator 124. The same components as those of the fuel cell 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The second metal separator 124 is provided with a fuel gas channel 40 on the surface 124a on the electrolyte membrane / electrode structure 16 side, and at the lower end in the gravity direction of the fuel gas channel 40 from the fuel gas channel 40. An anode drainage passage 44 for discharging generated water (back diffusion water) downward in the direction of gravity is provided. A part of the cooling medium flow path 38 is formed on the other surface 124b of the second metal separator 124.

  The electrolyte membrane / electrode structure 16 is configured similarly to the first electrolyte membrane / electrode structure 16a or the second electrolyte membrane / electrode structure 16b of the first embodiment.

  In the second embodiment configured as described above, the anode drain passage 44 is provided at the lower end in the gravity direction of the fuel gas passage 40. For this reason, the effect similar to said 1st Embodiment is acquired, such as it becomes possible to discharge | emit the produced water which tends to stay below the gravity direction in an electrode surface from the said electrode surface easily and reliably.

DESCRIPTION OF SYMBOLS 10, 120 ... Fuel cell 12, 122 ... Electric power generation unit 14, 18, 20, 124 ... Metal separator 16a, 16b ... Electrolyte membrane electrode assembly 22a ... Oxidant gas inlet communication hole 22b ... Oxidant gas outlet communication hole 24a ... Fuel gas inlet communication hole 24b ... Fuel gas outlet communication hole 25a ... Cooling medium inlet communication hole 25b ... Cooling medium outlet communication hole 26, 50 ... Oxidant gas flow path 32, 54 ... Cathode drain passages 34a, 34b, 46a, 46b, 64a, 64b ... uneven portions 36, 48, 56, 66 ... drainage channel 38 ... cooling medium channel 40 ... fuel gas channel 44, 62 ... anode drain channel 58 ... fuel gas channel 68, 70, 72 ... Seal member 74 ... Solid polymer electrolyte membrane 76 ... Cathode electrode 78 ... Anode electrodes 80 and 82 ... Resin frame member

Claims (3)

An electrolyte membrane / electrode structure provided with a pair of electrodes on both sides of the electrolyte membrane and a metal separator are laminated along the horizontal direction, and the electrode surface is vertically oriented along the direction of gravity and elongated in the horizontal direction. A fuel cell having a horizontally long shape and provided with a reaction gas flow path for allowing a reaction gas that is an oxidant gas or a fuel gas to flow along the longitudinal direction of the electrode surface,
At the lower end in the gravity direction of the reaction gas flow path, a drainage passage for discharging generated water from the reaction gas flow path downward in the gravity direction is provided,
The fuel cell according to claim 1, wherein the drainage passage is configured by a concavo-convex shape portion formed alternately on a surface of the metal separator on the side of the reactive gas flow channel and a surface opposite to the surface. The fuel cell according to claim 1, wherein a reaction gas outlet communication hole communicating with the reaction gas flow path and penetrating in the stacking direction is provided at a lower end of the metal separator in the horizontal direction,
A drainage channel communicates below the uneven shape portion,
The drainage channel extends in the longitudinal direction of the metal separator and communicates with the reaction gas outlet communication hole. The fuel cell according to claim 1 or 2, wherein the electrolyte membrane / electrode structure is provided with a resin frame member on an outer peripheral portion,
The drainage channel is formed between the resin frame member and the metal separator.

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