JP2013206876A - 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 a reactant gas passage in the direction of gravitational force, to be easily and reliably drained from the reactant gas passage.SOLUTION: A fuel cell 10 includes power generation units 12, each having 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 to a drainage passage 36. The first cathode drainage channel 32 has a plurality of connecting channels 32a that are defined by uneven portions 34a and 34b. The cross-sectional areas of the connecting channels 32a become gradually smaller in an oxidant gas flow direction.

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 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 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 (particularly, the oxidant gas channel) due to the action of gravity, and flooding due to condensed water may occur.

  Thus, for example, a fuel cell disclosed in Patent Document 1 is known. In this fuel cell, as shown in FIG. 19, the principal surfaces 1a and 1c of the cell 1 perpendicular to the stacking direction of the cells 1 are arranged in the vertical direction.

  In each cell 1, when the main surfaces 1a and 1c of the cell 1 are arranged in the vertical direction, among the inner surfaces of the anode side separator 2a and the cathode side separator 2c, from the catalyst layers 3a and 3c and the diffusion layers 4a and 4c. In addition, an anode-side groove portion 5a and a cathode-side groove portion 5c for the drainage channel are provided in a portion located below.

  The anode-side groove 5a is not in communication with the fuel gas flow path 6a of the anode-side separator 2a, and has a function of collecting water in the cell 1. The cathode-side groove 5c is not in communication with the oxidant gas flow path 6c of the cathode-side separator 2c, and has a function of collecting water in the cell 1.

  In the fuel cell configured as described above, water falls due to gravity from the power generation region located above the anode-side groove 5a and the cathode-side groove 5c and is collected in the anode-side groove 5a and the cathode-side groove 5c. Therefore, the water in the power generation region can be removed by gravity.

JP 2006-351323 A

  In Patent Document 1, the anode side groove 5a and the cathode side groove 5c do not communicate with the fuel gas channel 6a and the oxidant gas channel 6c. Therefore, the water in the fuel gas channel 6a and the oxidant gas channel 6c passes through the diffusion layers 4a and 4c and is collected by its own weight in the anode-side groove portion 5a and the cathode-side groove portion 5c.

  However, during power generation, a large amount of generated water is generated particularly in the oxidant gas flow path 6c. For this reason, a large amount of stagnant water is likely to be generated in the oxidant gas flow path 6c compared to the amount of water that permeates the diffusion layer 4c. Accordingly, there is a problem that water cannot be effectively removed from the oxidant gas flow path 6c to the cathode side groove 5c.

  Therefore, stagnant water remains in the oxidant gas flow path 6c, and a smooth flow of the oxidant gas is prevented, and a cross leak may occur from the anode side to the cathode side.

  The present invention solves this type of problem, and easily and reliably discharges generated water that tends to stay below the direction of gravity in the reaction gas flow path from the reaction gas flow path with a simple configuration. An object of the present invention is to provide a fuel cell capable of performing

  In the present invention, an electrolyte membrane / electrode structure provided with a pair of electrodes on both sides of an electrolyte membrane and a 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 that is an oxidant gas or a fuel gas flows along the longitudinal direction of the electrode surface.

  In this fuel cell, a drainage flow path extending in the longitudinal direction of the separator is provided below the reaction gas flow path in the gravity direction, and the bottom end in the gravity direction of the reaction gas flow path and the drainage flow path are provided. A plurality of connecting passages communicating with each other. The connection passage is configured such that the passage cross-sectional area gradually decreases in the reaction gas flow direction of the reaction gas passage.

  Further, in this fuel cell, it is preferable that the interval between the adjacent connection passages is configured to become smaller in the reaction gas flow direction.

  Furthermore, in this fuel cell, a reaction gas outlet communication hole that communicates with the reaction gas flow path and penetrates in the stacking direction is provided at a lower end of the horizontal end of the separator, and the reaction gas outlet communication hole includes a drain flow path. Are preferably communicated.

  According to the present invention, when the reaction gas is circulated along the electrode surface that is long in the horizontal direction, water is generated by the reaction, and the water moves downward in the gravity direction of the reaction gas channel. Easy to stay. At that time, a connecting passage is provided below the reaction gas passage in the gravity direction, and the water that has moved downward in the gravity direction of the reaction gas passage is discharged from the connection passage to the drainage passage. .

  A large amount of product water is generated on the downstream side of the reactive gas flow direction in the reactive gas flow direction compared to the upstream side in the reactive gas flow direction. Here, the connecting passage is configured such that the passage cross-sectional area is gradually reduced toward the reaction gas flow direction of the reaction gas flow path, so that the pressure loss is increased. Accordingly, a relatively large amount of generated water staying downstream in the reaction gas flow direction is forcibly discharged from the connection passage to the drainage passage.

  Thereby, it is possible to easily and reliably discharge the generated water that tends to stay below the direction of gravity in the reaction gas channel with a simple configuration. For this reason, it is possible to satisfactorily suppress the occurrence of cross leak from the anode side to the cathode side due to the staying water in the lower part of the reaction gas channel.

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. It is a principal part exploded perspective explanatory view of the power generation unit which constitutes the fuel cell concerning a 3rd embodiment of the present invention. It is the XVIII-XVIII sectional view taken on the line of the said electric power generation unit in FIG. 2 is a cross-sectional explanatory 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 has a plurality of connection passages 32a configured by uneven portions 34a and 34b that are alternately press-formed on the surface 14a of the first metal separator 14 and the surface 14b opposite to the surface 14a. . As will be described later, the connecting passage 32a is configured such that the passage sectional area gradually decreases in the oxidant gas flow direction (arrow B1 direction) of the first oxidant gas flow channel 26.

  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. . Each concavo-convex shape portion 34b has the same depth dimension (dimension in the direction of arrow A), and width dimension (dimension in the direction of arrow B) stepwise in the oxidant gas flow direction (arrow B1 direction). Is set to be small (see FIG. 6). Each concavo-convex shape part 34a is set so that each width dimension becomes small in steps toward the oxidant gas flow direction. In addition, each uneven | corrugated shaped part 34a may set each width dimension to the same dimension.

  The connecting passage 32a is configured such that the width dimension (dimension in the direction of arrow B) gradually decreases toward the oxidizing gas flow direction, that is, the passage cross-sectional area decreases. The interval between the adjacent connection passages 32a is configured to become smaller (or the same) in the oxidant gas flow direction.

  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. The connecting passages 32a are provided between the concavo-convex portions 34a, that is, along the concavo-convex portions 34b, and communicate the lowermost gravity direction lower end of the first oxidant gas passage 26 and the drainage passage 36.

  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 has a plurality of connection passages 44a constituted by concave and convex portions 46a and 46b that are alternately press-formed on the surface 18a of the second metal separator 18 and the surface 18b opposite to the surface 18a. . As will be described later, the connecting passage 44a is configured such that the passage sectional area gradually increases in the fuel gas flow direction (the direction of arrow B2) of the first fuel gas passage 40.

  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). . Each concavo-convex portion 46b has the same depth dimension (dimension in the direction of arrow A), and the width dimension (dimension in the direction of arrow B) increases stepwise toward the fuel gas flow direction ( (Or the same dimensions). Each concavo-convex shape part 46a is set so that each width dimension becomes large in steps toward the fuel gas flow direction (arrow B2 direction).

  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. The connection passage 44 a is provided between the uneven portions 46 a, that is, along the uneven portion 46 b, and communicates the lowest end in the gravity direction of the first fuel gas passage 40 and the drainage passage 48.

  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 has a plurality of connection passages 54 a configured by uneven portions 46 a and 46 b that are the back surface shape of the first anode drainage passage 44. As will be described later, the connecting passage 54a is configured such that the passage sectional area gradually decreases in the oxidant gas flow direction (arrow B1 direction) of the second oxidant gas flow path 50.

  Each concavo-convex shape portion 46a has the same depth dimension (dimension in the direction of arrow A), and the width dimension (dimension in the direction of arrow B) decreases stepwise toward the oxidant gas flow direction. Is set. The connecting passage 54a is configured such that the width dimension (dimension in the direction of arrow B) decreases stepwise in the oxidant gas flow direction, that is, the passage cross-sectional area decreases. The interval between the adjacent connection passages 54a is configured to become smaller (or the same) in the oxidant gas flow direction.

  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. The connection passage 54 a is provided between the uneven shape portions 46 b, that is, along the uneven shape portion 46 a, and communicates the bottom end in the gravity direction of the second oxidant gas flow channel 50 and the drainage flow channel 56.

  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 has a plurality of connection passages 62a configured by concave and convex portions 64a and 64b that are alternately press-formed on the surface 20a of the third metal separator 20 and the surface 20b opposite to the surface 20a. . As will be described later, the connection passage 62a is configured such that the passage cross-sectional area gradually increases in the fuel gas flow direction (arrow B2 direction) of the second fuel gas passage 58.

  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. . Each concavo-convex shape portion 64b has the same depth dimension (dimension in the direction of arrow A), and the width dimension (dimension in the direction of arrow B) increases stepwise toward the fuel gas flow direction ( (Or the same dimensions). Each concavo-convex shape portion 64a is set such that the width dimension thereof increases stepwise in the fuel gas flow direction (arrow B2 direction).

  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. The connecting passage 62a is provided between the concave and convex portions 64a, that is, along the concave and convex portion 64b, and communicates the lower end in the gravity direction of the second fuel gas passage 58 and the drainage passage 66.

  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 has a second protrusion that communicates the cooling medium inlet communication hole 25 a and the cooling medium outlet communication hole 25 b with the cooling medium flow path 38 on the surface 14 b of the first metal separator 14. The seal portion 68b is provided.

  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 is a second protrusion that communicates the cooling medium inlet communication hole 25 a and the cooling medium outlet communication hole 25 b with the cooling medium flow path 38 on the surface 20 b of the third metal separator 20. The seal portion 72b is 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.

  The first cathode drainage passage 32 is provided between the concavo-convex portions 34 a along the concavo-convex portions 34 b, and has a plurality of connections that communicates the lowermost gravity direction lower end of the first oxidant gas passage 26 and the drainage passage 36. A passage 32a is provided. For this reason, the water that has moved downward in the direction of gravity of the first oxidant gas flow path 26 is discharged from the connection passage 32 a to the drainage flow path 36.

  At that time, a larger amount of generated water is generated on the downstream side of the first oxidizing gas flow channel 26 in the oxidizing gas flow direction than on the upstream side in the oxidizing gas flow direction. Here, the connecting passage 32a is configured such that the passage sectional area gradually decreases in the oxidant gas flow direction (arrow B1 direction) of the first oxidant gas passage 26.

  Specifically, each of the concave and convex portions 34b has the same depth dimension, and is set so that the width dimension is gradually reduced toward the oxidant gas flow direction. The width dimension is gradually reduced toward the oxidant gas flow direction. For this reason, the pressure loss is set higher in the connecting passage 32a as it goes downstream in the oxidant gas flow direction.

  Therefore, a relatively large amount of generated water staying downstream in the oxidant gas flow direction is forcibly discharged to the drainage flow path 36 from the connection passage 32a having a high pressure loss on the downstream side. As a result, it is possible to easily and reliably discharge the generated water that tends to stay below the gravity direction in the first oxidant gas flow channel 26 from the first oxidant gas flow channel 26 with a simple configuration. The effect is obtained. For this reason, it is possible to satisfactorily suppress the occurrence of cross leak from the anode side to the cathode side due to the accumulated water in the lower portion of the first oxidant gas flow path 26.

  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 is less than the generated water in the first oxidant gas channel 26 and the second oxidant gas channel 50.

  Accordingly, the generated water that moves in the downward direction of gravity from the middle of the first fuel gas passage 40 and the second fuel gas passage 58 passes through the first anode drain passage 44 and the second anode drain passage 62 and passes through the drain passage. After flowing to 48 and 66, it is discharged to the fuel gas outlet communication hole 24b.

  In the first fuel gas channel 40 and the second fuel gas channel 58, the fuel gas inlet communication hole 24a and the fuel gas outlet communication hole 24b can be provided in reverse. Thereby, also in the anode side connecting passage, the width dimension gradually decreases in the fuel gas flow direction, and the pressure loss can be set higher as it goes downstream in the fuel gas flow direction.

  As shown in FIGS. 15 and 16, the fuel cell 120 according to the second embodiment of the present invention includes a plurality of power generation units 122 arranged in a horizontal direction (arrow A direction) or a vertical direction (arrow C direction). Laminated. 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 power generation unit 122 includes a first metal separator 124, a first electrolyte membrane / electrode structure 126a, a second metal separator 128, a second electrolyte membrane / electrode structure 126b, and a third metal separator 130.

  On the surface 124 a of the first metal separator 124, a first cathode drain for discharging generated water from the first oxidant gas flow channel 26 downward in the gravitational direction at the lower end in the gravity direction of the first oxidant gas flow channel 26. A passage 132 is provided. The first cathode drainage passage 132 has a plurality of connection passages 132a configured by uneven portions 134a and 134b that are alternately press-formed on the surface 124a of the first metal separator 124 and the surface 124b opposite to the surface 124a. .

  As shown in FIG. 16, the concavo-convex shape portion 134a has a protrusion shape (dent shape from the back surface) that bulges toward the first electrolyte membrane / electrode structure 126a side, while the concavo-convex shape portion 134b has an adjacent third It has a protruding shape that protrudes toward the metal separator 130 (a recessed shape from the back surface).

  Each uneven-shaped part 134b has the same width dimension (dimension in the direction of arrow B), and the depth dimension (dimension in the direction of arrow A) is stepped toward the oxidant gas flow direction (arrow B1 direction). Is set to be small (shallow). Each concavo-convex shape part 134a is set so that each width dimension becomes smaller in steps toward the oxidant gas flow direction. In addition, each uneven | corrugated shaped part 134a may set each width dimension to the same dimension.

  The connecting passage 132a is configured such that the depth dimension (dimension in the direction of arrow A) decreases stepwise in the oxidant gas flow direction, that is, the passage cross-sectional area decreases. The interval between the adjacent connection passages 132a is configured to become smaller (or the same) in the oxidant gas flow direction.

  The second metal separator 128 is provided with a first anode drain passage 136 on the first fuel gas passage 40 side and a second cathode drain passage 138 on the second oxidant gas passage 50 side. The first anode drainage passage 136 has a plurality of connection passages 136a configured by uneven portions 140a and 140b that are alternately press-formed on the surface 128a of the second metal separator 128 and the surface 128b opposite to the surface 128a. .

  As shown in FIG. 16, the concavo-convex shape portion 140a has a protrusion shape (dent shape from the back surface) that bulges toward the first electrolyte membrane / electrode structure 126a side, while the concavo-convex shape portion 140b includes the second electrolyte membrane. -It has a protruding shape (a recessed shape from the back surface) that bulges toward the electrode structure 126b.

  Each concavo-convex shape portion 140b has the same width dimension (dimension in the arrow B direction), and the depth dimension (dimension in the arrow A direction) is stepwise toward the fuel gas flow direction (arrow B2 direction). It is set to be large (deep). Each concavo-convex shape part 140a is set so that each width dimension becomes small in steps toward the oxidant gas flow direction.

  The second cathode drainage passage 138 has a plurality of connection passages 138a configured by the concave and convex portions 140a and 140b. Each concavo-convex shape portion 140a has the same width dimension (dimension in the arrow B direction), and the depth dimension (dimension in the arrow A direction) is stepwise toward the oxidant gas flow direction (arrow B1 direction). Is set to be small (shallow). The connecting passage 138a is configured such that the depth dimension (dimension in the direction of arrow A) decreases stepwise in the oxidant gas flow direction, that is, the passage cross-sectional area decreases. The interval between the adjacent connecting passages 138a is configured to become smaller (or the same) in the oxidant gas flow direction.

  The third metal separator 130 is provided with a second anode drain passage 142 on the second fuel gas channel 58 side. The second anode drainage passage 142 has a plurality of connection passages 142a configured by concave and convex portions 144a and 144b that are alternately press-formed on the surface 130a of the third metal separator 130 and the surface 130b opposite to the surface 130a. .

  As shown in FIG. 16, the concavo-convex shape portion 144a has a protruding shape (dent shape from the back surface) that bulges toward the second electrolyte membrane / electrode structure 126b, while the concavo-convex shape portion 144b is adjacent to the first It has a protruding shape that bulges to the metal separator 124 side (a recessed shape from the back surface).

  Each concavo-convex shape portion 144b has the same width dimension (dimension in the arrow B direction), and the depth dimension (dimension in the arrow A direction) gradually increases in the fuel gas flow direction (arrow B2 direction). It is set to be small (shallow). Each uneven | corrugated shaped part 144b is set so that each width dimension may become large gradually in the fuel gas flow direction.

  The first electrolyte membrane / electrode structure 126 a includes a first resin frame member 146. In the first resin frame member 146, as shown in FIG. 16, the surface 146a on the first metal separator 124 side is formed in a flat shape, while the surface 146b on the second metal separator 128 side is formed in each uneven shape portion. 140b is formed in a staircase shape that is stepped inwardly in the direction of arrow B2 so that 140b is arranged in a planar shape.

  In the second embodiment configured as described above, as shown in FIG. 15, the first oxidant gas flow path 26 has a lower end in the gravity direction of the first oxidant gas flow path 26 of the first metal separator 124. A first cathode drain passage 132 for discharging the generated water downward in the direction of gravity is provided.

  Further, as shown in FIG. 16, the first cathode drainage passage 132 has a plurality of connection passages 132 a configured by uneven portions 134 a and 134 b, and the connection passage 132 a is directed toward the oxidant gas flow direction. The depth dimension (dimension in the direction of arrow A) is decreased stepwise, that is, the passage cross-sectional area is decreased.

  Thus, the pressure loss is set higher in the connecting passage 132a as it goes downstream in the oxidant gas flow direction. For this reason, it is possible to easily and reliably discharge the generated water that tends to stay in the first oxidant gas flow channel 26 in the direction of gravity in the first oxidant gas flow channel 26 with a simple configuration. The same effects as those of the first embodiment are obtained. The same effect can be obtained in the second oxidant gas flow path 50.

  As shown in FIGS. 17 and 18, in the fuel cell 150 according to the third embodiment of the present invention, the plurality of power generation units 152 are arranged in the horizontal direction (arrow A direction) or the vertical direction (arrow C direction). Laminated. 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 power generation unit 152 is configured by sandwiching the electrolyte membrane / electrode structure 16 between the first metal separator 14 and the second metal separator 154. The second metal separator 154 is provided with a fuel gas channel 40 on the surface 154a on the electrolyte membrane / electrode structure 16 side, and at the lower end in the gravitational 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 154 b of the second metal separator 154.

  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 third embodiment configured as described above, the first cathode drain passage 32 is provided on the surface 14a of the first metal separator 14, and the first cathode drain passage 32 is first from the lower side in the gravity direction. A plurality of connecting passages 32 a that incline toward the oxidant gas flow direction of the oxidant gas flow path 26 are provided. The connecting passage 32a is configured such that the passage sectional area gradually decreases in the oxidant gas flow direction (arrow B1 direction) of the first oxidant gas passage 26.

  For this reason, it is possible to easily and reliably discharge the generated water that tends to stay in the first oxidant gas flow channel 26 in the direction of gravity in the first oxidant gas flow channel 26 with a simple configuration. The same effects as those of the first embodiment are obtained. Note that the third embodiment may be configured similarly to the second embodiment described above.

DESCRIPTION OF SYMBOLS 10, 120, 150 ... Fuel cell 12, 122, 152 ... Electric power generation unit 14, 18, 20, 124, 154 ... Metal separator 16a, 16b ... Electrolyte membrane and electrode structure 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 passage 32a, 44a, 54a, 62a, 132a, 136a, 138a, 142a ... Connecting passages 34a, 34b, 46a, 46b, 64a, 64b, 134a, 134b, 140a, 140b, 144a, 144b ... Uneven shape portions 36, 48, 56, 66 ... drainage channel 38 ... cooling medium channel 40 ... fuel gas channel 44, 62 ... anode drain channel 58 ... Fuel gas flow paths 68, 70, 72 ... Sealing member 74 ... Solid polymer electrolyte membrane 76 ... Cathode electrode 78 ... Anode electrode 80, 82 ... Resin frame member

Claims (3)

An electrolyte membrane / electrode structure in which a pair of electrodes are provided on both sides of the electrolyte membrane and a separator are stacked along the horizontal direction, and the electrode surface is vertically oriented along the gravitational direction and horizontally long. A fuel cell having a shape and provided with a reaction gas flow path for flowing a reaction gas that is an oxidant gas or a fuel gas along the longitudinal direction of the electrode surface,
A drainage flow path extending in the longitudinal direction of the separator is provided below the reaction gas flow path in the gravity direction,
A plurality of connecting passages for communicating the lowermost gravity direction lower end of the reaction gas flow path and the drainage flow path;
The fuel cell according to claim 1, wherein the connection passage is configured so that a cross-sectional area of the passage gradually decreases toward a reaction gas flow direction of the reaction gas passage.   2. The fuel cell according to claim 1, wherein an interval between the adjacent connection passages is configured to become smaller in the reaction gas flow direction. 3. 3. The fuel cell according to claim 1, wherein a reaction gas outlet communication hole communicating with the reaction gas flow path and penetrating in a stacking direction is provided at a lower end of the separator in the horizontal direction.
The fuel cell, wherein the drainage flow path communicates with the reaction gas outlet communication hole.

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