JP5876385B2 - Fuel cell - Google Patents

Description

  In the present invention, an electrolyte membrane / electrode structure and a separator are stacked along a horizontal direction, and an electrode surface has a vertically long shape along a gravitational direction and a horizontally long shape that is long in the horizontal direction. The present invention relates to a fuel cell provided with a wave-shaped reaction gas flow path that circulates 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 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. 15, 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 flow path 4a is discharged from the groove hole 7b through the fuel gas outlet manifold hole 7a to the outside of the fuel cell, and the water that has passed through the anode-side flow path 4a The water is discharged out of the fuel cell 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. to have a long oblong shape, reaction gas channel that is distributed along the longitudinal direction of the electrode surface reaction gas is an oxidant gas or fuel gas, when viewed from the laminate direction of the metal separator wave The present invention relates to a fuel cell provided in a shape .

In this fuel cell, the reactive gas flow path has a plurality of wavy flow channel grooves that are arranged in the direction of gravity and have a wavy cross section , and the lower end wavy flow that is the wavy flow path groove disposed at the lowest position in the gravity direction. the road grooves, have a drainage passage extending from the gravitational direction lowermost corrugated downward in the gravity direction, the drain passage is made is pressed into the metal separator, and the flow than the bottom corrugated flow grooves Road cross-sectional area is small .

Further, in this fuel cell, a reaction gas outlet communication hole that communicates with the reaction gas channel and penetrates in the stacking direction is provided at the lower end of the metal separator in the horizontal direction, and a drain channel is provided below the drain channel. It is preferable that the drainage flow path extends in the longitudinal direction of the metal separator and communicates with the reaction gas outlet communication hole while communicating.

  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 that time, the reaction gas flow path arranged at the lowermost part in the gravitational direction has a drainage passage extending downward from the lowermost part in the gravitational direction in the gravitational direction.

  For this reason, the water which moved below the gravitational direction of the electrode surface is smoothly discharged from the drainage passage to the outside of the electrode surface. Thereby, it becomes possible to discharge | emit easily and reliably from the said electrode surface the produced water which is easy to stay in the gravity direction downward direction in an electrode surface with a simple structure. 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 the 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. It is front explanatory drawing of the 1st metal separator which comprises the said electric power generation unit. 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 front explanatory drawing of the 1st electrolyte membrane and electrode structure which comprises the said electric power generation unit. It is front explanatory drawing of the 2nd electrolyte membrane and electrode structure which comprises the said electric power generation unit. 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 XI-XI sectional view taken on the line of FIG. 10 of the said electric power generation unit. It is the XII-XII sectional view taken on the line of the said electric power generation unit in FIG. It is front explanatory drawing of the 2nd metal separator which comprises the said electric power generation unit. It is principal part cross-sectional explanatory drawing of the electric power generation unit which comprises the fuel cell which concerns on the 4th Embodiment of this invention. 2 is an exploded perspective view of a fuel cell disclosed in Patent Document 1. FIG.

  As shown in FIGS. 1 to 3, 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 fuel cell 10 constitutes, for example, an in-vehicle fuel cell stack mounted on a fuel cell electric vehicle (not shown).

  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. 4, 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. The oxidant gas passage 26 is press-molded.

  The first oxidant gas flow channel 26 has a plurality of wave-shaped flow channel grooves 26a extending in the direction of arrow B, and a plurality of embosses in the vicinity of the inlet and the outlet of the first oxidant gas flow channel 26, respectively. An inlet embossed portion 28a and an outlet embossed portion 28b 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.

  The lower end wave-like channel groove portion 26ae disposed at the lowest position in the gravity direction of the first oxidant gas channel 26 has a drainage passage 32 extending downward from the wave-shaped gravity direction bottom portion in the gravity direction. Specifically, the lower end wavy channel groove portion 26ae extends in the horizontal direction (arrow B direction) by alternately providing bent portions or curved portions in the vertical direction (arrow C direction), and the lower bent portion or curved portion. The upper end side of the drainage passage 32 communicates with the center (lowermost position) of the section.

  Each drainage passage 32 is press-molded in the first metal separator 14, extends downward in the direction of gravity, and the lower end side thereof communicates with the drainage flow path 34. The drainage passage 32 is preferably set to have a small passage width and passage height so that only the generated water is discharged from the first oxidant gas passage 26 and the oxidant gas is not bypassed. The drainage passage 32 is set to have a channel cross-sectional area smaller than that of the lower-end corrugated channel groove 26ae.

  The drainage flow path 34 extends linearly in the horizontal direction and communicates with the oxidant gas outlet communication hole 22b. The drainage flow path 34 may be inclined downward in the gravitational direction toward the oxidant gas outlet communication hole 22b side. It is because drainage improves. Further, the drainage passage 32 may be provided by thinning out every predetermined number.

  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. 5, the first fuel gas that communicates the fuel gas inlet communication hole 24a and the fuel gas outlet communication hole 24b with the surface 18a of the second metal separator 18 facing the first electrolyte membrane / electrode structure 16a. The flow path 40 is press-molded.

  The first fuel gas channel 40 has a plurality of waved 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.

  As shown in FIG. 6, the surface 18b of the second metal separator 18 facing the second electrolyte membrane / electrode structure 16b is connected to the oxidant gas inlet communication hole 22a and the oxidant gas outlet communication hole 22b. The oxidant gas flow path 50 is press-molded. The second oxidant gas channel 50 has a plurality of wave-like 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.

  The lower end wave-like channel groove portion 50ae disposed at the lowest position in the gravitational direction of the second oxidant gas passage 50 has a drainage passage 54 extending downward from the wave-shaped gravity direction lower portion in the gravity direction. Specifically, the lower end wavy flow channel groove portion 50ae is provided with alternating bent portions or curved portions in the vertical direction (arrow C direction) and extends in the horizontal direction (arrow B direction). The upper end side of the drainage passage 54 communicates with the center (lowermost position) of the section.

  Each drainage passage 54 is press-molded in the second metal separator 18, extends downward in the direction of gravity, and the lower end side thereof communicates with the drainage flow path 56. The drainage passage 54 is preferably set to have a small passage width and passage height so that only the generated water is discharged from the second oxidant gas passage 50 and the oxidant gas is not bypassed. The drainage flow channel 56 extends linearly in the horizontal direction and communicates with the oxidant gas outlet communication hole 22b. The drainage flow channel 56 may be inclined downward in the gravitational direction toward the oxidant gas outlet communication hole 22b side. It is because drainage improves.

  As shown in FIG. 7, 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 waved 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 FIG. 1, the supply hole 60 a is disposed on the inner side (fuel gas flow path side) of the supply hole 42 a of the second metal separator 18, while the discharge hole 60 b is formed on the second metal separator 18. It is arranged on the inner side (fuel gas flow path side) than the discharge hole portion 42b.

  A part of the coolant flow path 38, which 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.

  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. 4, 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. 5, the second seal member 70 surrounds the supply hole portion 42 a, 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 these. The first convex seal portion 70a is provided.

  As shown in FIG. 6, 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. 7, the third seal member 72 surrounds the supply hole portion 60 a and the discharge hole portion 60 b and the second fuel gas flow path 58 on the surface 20 a of the third metal separator 20 and communicates them. A first convex seal portion 72a.

  The third seal member 72 includes a second convex seal portion 72b that communicates the outer periphery of the cooling medium inlet communication hole 25a, the cooling medium outlet communication hole 25b, and the cooling medium flow path 38 on the surface 20b of the third metal separator 20. Have.

  As shown in FIGS. 2 and 3, the first electrolyte membrane / electrode structure 16a and the second electrolyte membrane / electrode structure 16b are, for example, solid polymer electrolyte membranes in which a perfluorosulfonic acid thin film is impregnated with water. 74 and a cathode electrode 76 and an anode electrode 78 sandwiching the solid polymer electrolyte membrane 74. 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 FIG. 1, an oxidant gas inlet communication hole 22a and a first oxidant gas flow path are formed on the surface of the first resin frame member 80 provided on the first electrolyte membrane / electrode structure 16a on the cathode electrode 76 side. 26, an inlet buffer portion 84a is provided between the outlet side of the oxidant gas outlet communication hole 22b and the outlet side of the first oxidant gas flow path 26. A portion 84b is provided.

  As shown in FIG. 8, 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 FIG. 1, the oxidant gas inlet communication hole 22a and the second oxidant gas flow path are formed on the surface of the second resin frame member 82 provided on the second electrolyte membrane / electrode structure 16b on the cathode electrode 76 side. 50, an inlet buffer portion 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. 9, 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, 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 further 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, 4 and 6, 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. 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 FIGS. 1 and 8, 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. Further, as shown in FIGS. 1 and 9, the fuel gas is supplied from the fuel gas inlet communication hole 24a to the inlet buffer 90a through the supply hole 60a. 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 FIG. 1, the fuel gas moves in the direction of arrow B along the first fuel gas flow path 40, is supplied to the anode electrode 78 of the first electrolyte membrane / electrode structure 16a, and the second fuel. It moves in the direction of arrow B along the 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 an elongated shape in the horizontal direction, and the generated water moves in the downward direction of gravity from the middle of the first oxidant gas flow path 26 via carbon paper or the like. However, it tends to stay below the power generation surface in the direction of gravity.

  In this case, in the first embodiment, as shown in FIGS. 2 and 4, a first oxidant gas flow path 26 is provided on the surface 14 a of the first metal separator 14. And the lower end wave-like channel groove part 26ae arrange | positioned in the gravity direction lowermost part of the 1st oxidizing gas flow path 26 has the drainage channel 32 extended in the gravity direction downward from the wave-like gravity direction lowermost part. . Specifically, the lower end wavy channel groove portion 26ae extends in the horizontal direction (arrow B direction) by alternately providing bent portions or curved portions in the vertical direction (arrow C direction), and the lower bent portion or curved portion. The upper end side of the drainage passage 32 communicates with the center (lowermost position) of the section.

  For this reason, the generated water generated in the first oxidant gas passage 26 moves smoothly downward in the direction of gravity via carbon paper or the like, and is then smoothly discharged from the drain passage 32 to the outside of the electrode surface. The produced water flows into the drainage flow path 34 communicating with the drainage passage 32, moves in the direction of arrow B along the drainage flow path 34, and is discharged to the oxidant gas outlet communication hole 22b.

  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.

  In the first embodiment, the drainage passage 32 and the drainage passage 54 are employed in the first oxidant gas passage 26 and the second oxidant gas passage 50, but the present invention is not limited to this. For example, a similar drainage passage may be provided in the first fuel gas channel 40 and the second fuel gas channel 58.

  As shown in FIGS. 10 to 12, 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 electrolyte membrane / electrode structure 16 is configured in the same manner as the first electrolyte membrane / electrode structure 16a or the second electrolyte membrane / electrode structure 16b of the first embodiment.

  As shown in FIG. 13, the second metal separator 124 is provided with a first fuel gas flow path 40 on a surface 124 a on the electrolyte membrane / electrode structure 16 side. The lower end wave-like channel groove portion 40ae disposed at the lowest position in the gravity direction of the first fuel gas channel 40 has a drainage passage 126 extending downward from the wave-shaped gravity direction bottom portion in the gravity direction. Specifically, the lower end wavy channel groove portion 40ae extends in the horizontal direction (arrow B direction) by alternately providing bent portions or curved portions in the vertical direction (arrow C direction), and the lower bent portion or curved portion. The upper end side of the drainage passage 126 communicates with the center (lowermost position) of the section.

  Each drainage passage 126 is press-molded into the second metal separator 124, extends downward in the direction of gravity, and communicates with the drainage flow path 128 at the lower end of each drainage passage 126. The drainage passage 126 is preferably set to have a small passage width and passage height so that only the generated water is discharged from the first fuel gas passage 40 and the fuel gas is not bypassed. The drainage flow path 128 extends linearly in the horizontal direction and communicates with the fuel gas outlet communication hole 24b. The drainage flow path 128 may be inclined downward in the gravitational direction toward the fuel gas outlet communication hole 24b. It is because drainage improves. A part of the cooling medium flow path 38 is formed on the other surface 124b of the second metal separator 124.

  In the second embodiment configured as described above, the lower end wavy flow channel groove portion 40ae disposed at the lowermost position in the gravitational direction of the first fuel gas flow path 40 extends from the lowermost portion of the wavy shape in the gravitational direction downward in the gravitational direction. It has an existing drainage passage 126. For this reason, the generated water that has diffused back into the first fuel gas channel 40 moves smoothly downward in the direction of gravity via carbon paper or the like, and is then smoothly discharged from the drainage passage 126 to the outside of the electrode surface. Further, the generated water flows into the drainage flow path 128 communicating with the drainage passage 126, moves in the direction of arrow B along the drainage flow path 128, and is discharged to the fuel gas outlet communication hole 24b.

  Therefore, in the first fuel gas flow path 40, 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 the electrode surface, etc. The same effect as in the first embodiment can be obtained.

  As shown in FIG. 14, the fuel cell 130 according to the third embodiment of the present invention is configured by stacking a plurality of power generation units 132. 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 132 includes the first metal separator 14, the first electrolyte membrane / electrode structure 16 a, the second metal separator 134, the second electrolyte membrane / electrode structure 16 b, and the third metal separator 20. The second metal separator 134 is alternately provided with drainage passages 54 a communicating with the first fuel gas passage 40 and drainage passages 54 b communicating with the second oxidant gas passage 50 on both sides.

  Therefore, in the first fuel gas flow path 40 and the second oxidant gas flow path 50, the generated water that easily stays in the gravity direction in the electrode surface is easily and reliably discharged from the electrode surface with a simple configuration. For example, the same effects as those of the first and second embodiments can be obtained.

DESCRIPTION OF SYMBOLS 10, 120, 130 ... Fuel cell 12, 122, 132 ... Electric power generation unit 14, 18, 20, 124, 134 ... Metal separator 16, 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 paths 26a, 40a, 50a, 58a ... Wave channel grooves 26ae, 40ae, 50ae ... Lower end wavy channel grooves 32, 54, 54a, 54b, 126 ... Drain passages 34, 56, 128 ... Drain channels 38 ... Cooling medium channels 40, 58 ... Fuel gas Flow path 68, 70, 72 ... Seal member 74 ... Solid polymer electrolyte membrane 76 ... Cathode electrode 78 ... Anode electrode 80, 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. It has a horizontally long shape, reaction gas channel that is distributed along the longitudinal direction of the electrode surface reaction gas is an oxidant gas or fuel gas is provided to the waveform shape as viewed from the lamination direction of the metal separator A fuel cell,
The reactive gas flow path has a plurality of wavy flow channel grooves that are arranged in the direction of gravity and have a wavy cross section.
Lower corrugated flow grooves is the wavy passage grooves are arranged in the direction of gravity lowermost, have a water discharge passage extending downward in the gravity direction from the direction of gravity bottom of the wave shape,
The fuel cell according to claim 1, wherein the drainage passage is press-molded in the metal separator and has a channel cross-sectional area smaller than that of the lower-end corrugated channel groove . 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,
Under the drainage passage, a drainage channel communicates,
The drainage channel extends in the longitudinal direction of the metal separator and communicates with the reaction gas outlet communication hole. 3. The fuel cell according to claim 1, wherein the reaction gas channel includes an oxidant gas channel and a fuel gas channel,
A first drainage passage is formed on the first surface of the metal separator where the oxidant gas flow path is provided, while a second drainage is formed on the second surface of the metal separator where the fuel gas flow path is provided. A passage is formed,
The fuel cell according to claim 1, wherein the first drainage passage and the second drainage passage are alternately provided on the first surface and the second surface.

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