JP5918037B2 - Fuel cell - Google Patents

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 along a horizontal direction, and an electrode surface has a vertical posture along a gravity direction, The present invention relates to a fuel cell provided with a reaction gas flow path for allowing gas to flow along the electrode surface.

  For example, in a polymer electrolyte fuel cell, an electrolyte membrane / electrode structure (MEA) in which an anode electrode and a cathode electrode are disposed on both sides of a solid polymer electrolyte membrane made of a polymer ion exchange membrane is sandwiched between separators. Power generation cells (unit cells). In a fuel cell, several tens to several hundreds of power generation cells are usually stacked and used, for example, as an in-vehicle fuel cell stack.

  In a fuel cell, a so-called internal manifold is often configured to supply a fuel gas and an oxidant gas, which are reaction gases, to the anode electrode and the cathode electrode of each of the stacked power generation cells.

  The internal manifold has a reaction gas inlet communication hole (fuel gas inlet communication hole, oxidant gas inlet communication hole) and a reaction gas outlet communication hole (fuel gas outlet communication hole, oxidant gas) that are provided through the power generation cell in the stacking direction. Outlet communication hole). The reaction gas inlet communication hole communicates with the inlet side of the reaction gas channel (fuel gas channel, oxidant gas channel) for supplying the reaction gas along the electrode surface, while the reaction gas outlet communication hole is used for the reaction gas. It communicates with the outlet side of the gas flow path.

  For example, as shown in FIG. 9, the fuel cell separator disclosed in Patent Document 1 is provided with an inlet manifold 1a and an outlet manifold 1b at diagonal positions, and a gas flow path 2 is formed in the separator surface. Has been.

  The gas flow path 2 has a flow path width formed wider than the passage widths of the inlet manifold 1a and the outlet manifold 1b, and has a main flow path portion 3 provided with ribs 3a for dividing the flow path into a plurality of sections, and the inlet manifold 1a. And a distribution section (buffer section) 4 and a junction section (buffer section) 5 disposed between the outlet manifold 1b and the main flow path section 3.

  The distribution section 4 is provided with ribs 4 a that divide the flow path into a plurality of parts, and a gap 4 b is formed between the end of the rib 4 a and the rib 3 a of the main flow path section 3. The merging portion 5 is provided with ribs 5 a that divide the flow path into a plurality, and a gap 5 b is formed between the end of the rib 5 a and the rib 3 a of the main flow path portion 3.

JP 2006-172924 A

  In the above-mentioned Patent Document 1, the main flow path portion 3 provided in the power generation section has a function of allowing the reaction gas to flow well over the entire power generation surface, while the distribution section 4 and the merge section 5 are configured to flow the reaction gas. It has a function to perform distribution control and drainage control.

  However, when the fuel cell separators are stacked in the horizontal direction, the generated water tends to stay in the junction 5. In addition, in the merging portion 5, condensation is likely to occur due to external heat dissipation. For this reason, stagnant water is also generated in the main flow path portion 3 connected to the merge portion 5. Therefore, in the water retention portion, ion elution from the separator and noble metal elution from the electrode are caused, and there is a concern about deterioration of the electrolyte membrane and electrode performance.

  An object of the present invention is to solve this kind of problem, and to provide a fuel cell that does not generate stagnant water in a power generation region and that can effectively suppress deterioration of an electrolyte membrane. To do.

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 stacked along a horizontal direction, and an electrode surface has a vertical posture along a gravity direction, the separator, a reaction gas flow path along the electrode surfaces Ru was circulated reaction gas horizontally, the reaction gas supply passage for circulating the reaction gas in the stacking direction of the separator and the membrane electrode assembly The electrolyte membrane / electrode structure relates to a fuel cell in which a resin frame member is integrally provided on an outer peripheral portion.

In this fuel cell, the resin frame member and the separator have a contact portion that contacts each other and closes the lower end in the gravity direction of the reaction gas channel at a position spaced downward from the lower end of the electrolyte membrane in the direction of gravity. between the separator and the resin frame member, said located and outside the power generation region in the direction of gravity below the contact portion, the bypass passage is provided for connecting the reactant gas discharge passage from the reaction gas supply passage ing.

  Further, in this fuel cell, a first reactive gas flow path is formed between one side of the electrolyte membrane / electrode structure and the first separator, and the other side of the electrolyte membrane / electrode structure is connected to the first side. A second reactive gas channel is formed between the two separators and the bypass channel is one of the resin frame member and the first separator or the second separator along the stacking direction. It is preferable to form only between.

  Further, in this fuel cell, an inlet buffer part is provided between the reactive gas inlet communication hole and the reactive gas flow path, and the bypass flow path is connected to the reactive gas inlet communication hole via the inlet buffer part. It is preferable to be connected.

  Furthermore, in this fuel cell, the bypass flow path is connected to the reaction gas outlet communication hole via the connection flow path, the connection flow path is disposed below the outlet of the bypass flow path, and The bottom of the reaction gas outlet communication hole is preferably disposed below the connection flow path.

  According to the present invention, the bypass flow path is formed between the resin frame member and the separator. For this reason, the electrolyte membrane is independent from the bypass flow path, and even if the stagnant water is generated in the bypass flow path, the electrolyte membrane can be reliably prevented from being deteriorated by the stagnant water.

  Moreover, the bypass channel is provided outside the power generation region. Therefore, good power generation is reliably performed without causing a supply failure of the reaction gas supplied to the power generation region. Thereby, with a simple configuration, no stagnant water is generated in the power generation region, and deterioration of the electrolyte membrane can be effectively suppressed.

It is a principal part disassembled perspective explanatory drawing of the electric power generation unit which comprises the fuel cell concerning 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. 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 front explanatory drawing 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 explanatory drawing of the fuel cell separator currently disclosed by patent document 1. FIG.

  As shown in FIGS. 1 and 2, a fuel cell 10 according to an embodiment of the present invention includes a power generation unit 12, and the plurality of power generation units 12 are stacked on each other along a horizontal direction (direction of arrow A). 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 that are arranged in a standing posture. Is provided.

  The first metal separator 14, the second metal separator 18, and the third metal separator 20 are stacked along the horizontal direction, and the electrode surface has a vertically long shape along the gravity direction and a horizontally long shape that is long in the horizontal direction. Have.

  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. Instead of the first metal separator 14, the second metal separator 18, and the third metal separator 20, for example, a carbon separator may be used.

  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). An oxidant gas inlet communication hole (reactive gas inlet communication hole) 22a for supplying an oxidant gas, for example, an oxygen-containing gas, and a fuel gas communicate with each other in the direction of arrow A at one end edge in the side direction. For example, a fuel gas outlet communication hole (reaction gas outlet communication hole) 24b for discharging the hydrogen-containing gas is provided.

  A fuel gas inlet communication hole (reactive gas inlet communication hole) 24a for communicating with each other in the direction of arrow A and supplying fuel gas to the other edge of the long side direction (arrow B direction) of the power generation unit 12; And an oxidant gas outlet communication hole (reaction gas outlet communication hole) 22b for discharging the oxidant gas.

  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. 3, 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 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 buffer portion 28 having a portion 28a and an outlet buffer portion 29 having a plurality of embossed portions 29a are provided. Instead of the wavy flow channel groove 26a, a straight flow channel may be adopted.

  A plurality of inlet connection grooves 30a constituting a bridge portion are formed between the inlet buffer portion 28 and the oxidant gas inlet communication hole 22a, while the outlet buffer portion 29 and the oxidant gas outlet communication hole 22b are formed. A plurality of outlet connection grooves 30b constituting the bridge portion are formed therebetween.

  As shown in FIG. 1, a cooling medium flow path 32 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 flow path 32 is formed by overlapping the back surface shape of the first oxidant gas flow channel 26 and the back surface shape of the second fuel gas flow channel 50 described later.

  As shown in FIG. 4, the surface 18a of the second metal separator 18 facing the first electrolyte membrane / electrode structure 16a has a first fuel gas communicating with the fuel gas inlet communication hole 24a and the fuel gas outlet communication hole 24b. A flow path 34 is formed. The first fuel gas channel 34 has a plurality of waved channel grooves 34a extending in the direction of arrow B. Instead of the waved channel groove 34a, a linear channel groove may be adopted.

  An inlet connection flow path 36 a that connects the fuel gas inlet communication hole 24 a and the first fuel gas flow path 34 is provided, and an outlet connection flow that connects the fuel gas outlet communication hole 24 b and the first fuel gas flow path 34. A path 36b is provided. The inlet connection flow path 36a has a plurality of supply holes 38a provided in the vicinity of the fuel gas inlet communication hole 24a, while the outlet connection flow path 36b has a plurality of discharge holes provided in the vicinity of the fuel gas outlet communication hole 24b. It has a part 38b.

  A first bypass flow path 42 that is located below the first fuel gas flow path 34 in the direction of gravity and outside the power generation area 40 (below the power generation area 40) and connects the fuel gas inlet communication hole 24a to the fuel gas outlet communication hole 24b. Is provided. As shown in FIG. 2, the first bypass flow path 42 is formed between a first resin frame member 74 and a second metal separator 18 to be described later, and is independent (separated from) the solid polymer electrolyte membrane 68. Provided).

  The lower end position 36bu of the outlet connection channel 36b is disposed below the outlet lower end position 42u of the first bypass channel 42, and the bottom 24bu of the fuel gas outlet communication hole 24b is the lower end of the outlet connection channel 36b. It arrange | positions below the position 36bu.

  As shown in FIG. 5, the second metal separator 18 has a second surface 18b that communicates with the oxidant gas inlet communication hole 22a and the oxidant gas outlet communication hole 22b on the surface 18b facing the second electrolyte membrane / electrode structure 16b. An oxidant gas flow path 44 is formed. The second oxidant gas channel 44 has a plurality of wave-like channel grooves 44a extending in the arrow B direction. Instead of the waved channel groove 44a, a linear channel groove may be adopted.

  A plurality of inlet connection grooves 46a are formed in the vicinity of the oxidant gas inlet communication hole 22a, while a plurality of outlet connection grooves 46b are formed in the vicinity of the oxidant gas outlet communication hole 22b.

  In the vicinity of the fuel gas inlet communication hole 24a, an inlet connection channel 36a is formed, and an inlet connection groove 48a that connects the supply hole 38a and the fuel gas inlet communication hole 24a is formed. In the vicinity of the fuel gas outlet communication hole 24b, an outlet connection channel 36b is formed, and an outlet connection groove 48b that connects the discharge hole 38b and the fuel gas outlet communication hole 24b is formed.

  As shown in FIG. 2, the second metal separator 18 makes the back surface side of the first bypass passage 42 abut on a second resin frame member (described later) 76 constituting the second electrolyte membrane / electrode structure 16b. The gap for providing the flow path is not provided on the second oxidant gas flow path 44 side. This is to ensure a large dimension in the stacking direction of the first bypass channel 42.

  As shown in FIG. 6, 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 50 is formed. The second fuel gas channel 50 has a plurality of waved channel grooves 50a extending in the direction of arrow B. Instead of the waved channel groove portion 50a, a linear channel groove may be adopted.

  An inlet connection flow path 52 a that connects the fuel gas inlet communication hole 24 a and the second fuel gas flow path 50 is provided, and an outlet connection flow that connects the fuel gas outlet communication hole 24 b and the second fuel gas flow path 50. A path 52b is provided. The inlet connection channel 52a has a plurality of supply holes 54a provided in the vicinity of the fuel gas inlet communication hole 24a, while the outlet connection channel 52b has a plurality of discharge holes provided in the vicinity of the fuel gas outlet communication hole 24b. It has a portion 54b.

  As shown in FIG. 1, the supply hole 54 a is disposed on the inner side (fuel gas flow path side) of the supply hole 38 a of the second metal separator 18, while the discharge hole 54 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 38b.

  As shown in FIG. 6, the fuel gas outlet communication hole 24a is connected to the fuel gas inlet communication hole 24a by being located below the second fuel gas flow path 50 in the gravity direction and outside the power generation area 56 (below the power generation area 56). A second bypass channel 58 is provided. The lower end position 52bu of the outlet connection channel 52b is disposed below the outlet lower end position 58u of the second bypass channel 58, and the bottom 24bu of the fuel gas outlet communication hole 24b is the lower end of the outlet connection channel 52b. It arranges below position 52bu.

  A part of the coolant flow path 32 that is the back surface shape of the second fuel gas flow path 50 is formed on the surface 20 b of the third metal separator 20. In the surface 20b of the third metal separator 20, an inlet connection channel 52a is formed, and an inlet connection groove 60a that connects the supply hole portion 54a and the fuel gas inlet communication hole 24a is formed. On the surface 20b, an outlet connection channel 52b is formed, and an outlet connection groove 60b that connects the discharge hole portion 54b and the fuel gas outlet communication hole 24b is formed.

  As shown in FIG. 1, the first seal member 62 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 64 is integrally formed on the surfaces 18a and 18b of the second metal separator 18 around the outer peripheral edge 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 66 is integrally formed around the outer peripheral edge of the third metal separator 20.

  Examples of the first seal member 62, the second seal member 64, and the third seal member 66 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. 3, the first seal member 62 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 a first oxidant gas flow path 26. The first convex seal portion 62a that communicates with the outer periphery of the first convex seal portion 62a. As shown in FIG. 1, the first seal member 62 is a second protrusion that communicates the cooling medium inlet communication hole 25 a, the cooling medium outlet communication hole 25 b, and the cooling medium flow channel 32 on the surface 14 b of the first metal separator 14. The seal portion 62b is provided.

  As shown in FIG. 4, the second seal member 64 surrounds the supply hole 38 a and the discharge hole 38 b and the first fuel gas flow path 34 on the surface 18 a of the second metal separator 18, and communicates these. The first convex seal portion 64a is provided.

  As shown in FIG. 5, the second seal member 64 communicates the outer periphery of the oxidant gas inlet communication hole 22a, the oxidant gas outlet communication hole 22b, and the second oxidant gas flow path 44 on the surface 18b. It has two convex seal parts 64b.

  As shown in FIG. 6, the third seal member 66 surrounds the supply hole portion 54 a and the discharge hole portion 54 b and the second fuel gas channel 50 on the surface 20 a of the third metal separator 20, and communicates these. A first convex seal portion 66a.

  The third seal member 66 has a second convex seal portion 66 b that communicates the cooling medium inlet communication hole 25 a, the cooling medium outlet communication hole 25 b, and the cooling medium flow path 38 on the surface 20 b of the third metal separator 20.

  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 68 in which a thin film of perfluorosulfonic acid is impregnated with water, A cathode electrode 70 and an anode electrode 72 sandwiching the solid polymer electrolyte membrane 68 are provided. The cathode electrode 70 constitutes a stepped MEA having a planar dimension (surface dimension) smaller than the planar dimension (surface dimension) of the anode electrode 72 and the solid polymer electrolyte membrane 68.

  The cathode electrode 70, the anode electrode 72, and the solid polymer electrolyte membrane 68 may be set to the same plane dimension (surface dimension), and the anode electrode 72 may be the cathode electrode 70 and the solid polymer electrolyte. The film 68 may have a planar dimension (surface dimension) smaller than the planar dimension (surface dimension).

  The cathode electrode 70 and the anode electrode 72 are formed by uniformly applying a gas diffusion layer (not shown) made of carbon paper or the like and porous carbon particles carrying a platinum alloy on the surface thereof 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 68.

  The first electrolyte membrane / electrode structure 16a is located outside the terminal portion of the cathode electrode 70, and the first resin frame member 74 is integrally formed on the outer peripheral edge of the solid polymer electrolyte membrane 68 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 70, and a second resin frame member 76 is integrally formed on the outer peripheral edge of the solid polymer electrolyte membrane 68 by, for example, injection molding or the like. Is done. As the resin material constituting the first resin frame member 74 and the second resin frame member 76, for example, engineering plastics, super engineering plastics, etc. are adopted in addition to general-purpose plastics.

  As shown in FIG. 1, the inlet of the first resin frame member 74 on the cathode electrode 70 side is located between the oxidant gas inlet communication hole 22 a and the inlet side of the first oxidant gas flow path 26. A buffer portion 78 a is provided, and an outlet buffer portion 78 b is provided between the oxidant gas outlet communication hole 22 b and the outlet side of the first oxidant gas flow channel 26.

  The inlet buffer part 78a has a plurality of linear inlet guide channels 80a and a plurality of embossed parts 82a. The outlet buffer portion 78b has a plurality of linear outlet guide channels 80b and a plurality of embossed portions 82b.

  As shown in FIG. 7, an inlet buffer portion 84 a is provided on the surface of the first resin frame member 74 on the anode electrode 72 side, located between the fuel gas inlet communication hole 24 a and the first fuel gas flow path 34. In addition, an outlet buffer portion 84 b is provided between the fuel gas outlet communication hole 24 b and the first fuel gas flow path 34.

  The inlet buffer portion 84a has a plurality of linear inlet guide channels 86a and a plurality of embossed portions 88a. The outlet buffer portion 84b has a plurality of linear outlet guide channels 86b and a plurality of embossed portions 88b. As shown in FIGS. 4 and 7, the first bypass passage 42 is connected to the fuel gas inlet communication hole 24a via the inlet buffer portion 84a.

  As shown in FIG. 1, the inlet buffer portion 90 a is located on the surface of the second resin frame member 76 on the cathode electrode 70 side, between the oxidant gas inlet communication hole 22 a and the second oxidant gas flow path 44. Is provided, and an outlet buffer 90b is provided between the oxidant gas outlet communication hole 22b and the second oxidant gas flow path 44.

  The inlet buffer portion 90a includes a plurality of linear inlet guide channels 92a and a plurality of embossed portions 94a. The outlet buffer portion 90b has a plurality of linear outlet guide channels 92b and a plurality of embossed portions 94b.

  As shown in FIG. 8, the surface of the second resin frame member 76 on the anode electrode 72 side is provided with an inlet buffer portion 96a located between the fuel gas inlet communication hole 24a and the second fuel gas flow path 50. In addition, an outlet buffer portion 96b is provided between the fuel gas outlet communication hole 24b and the second fuel gas flow path 50.

  The inlet buffer part 96a has a plurality of linear inlet guide channels 98a and a plurality of embossed parts 100a. The outlet buffer part 96b has a plurality of linear outlet guide channels 98b and a plurality of embossed parts 100b. As shown in FIGS. 6 and 8, the second bypass flow path 58 is connected to the fuel gas inlet communication hole 24a via the inlet buffer portion 96a.

  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. 32 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 FIGS. 1 and 3, 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 78a. The As shown in FIGS. 1 and 5, the oxidant gas is introduced into the second oxidant gas flow path 44 of the second metal separator 18 from the oxidant gas inlet communication hole 22a through the inlet buffer portion 90a.

  As shown in FIGS. 1, 3, and 5, the oxidant gas moves in the direction of arrow B (horizontal direction) along the first oxidant gas flow path 26, so that the first electrolyte membrane / electrode structure 16a In addition to being supplied to the cathode electrode 70, it moves in the direction of arrow B along the second oxidant gas flow path 44, and is supplied to the cathode electrode 70 of the second electrolyte membrane / electrode structure 16b.

  On the other hand, as shown in FIGS. 1, 4 and 7, the fuel gas is supplied from the fuel gas inlet communication hole 24a to the inlet buffer part 84a through the supply hole part 38a. The fuel gas is supplied to the first fuel gas channel 34 of the second metal separator 18 through the inlet buffer portion 84a. As shown in FIGS. 1, 6 and 8, the fuel gas is supplied from the fuel gas inlet communication hole 24a to the inlet buffer part 96a through the supply hole part 54a. The fuel gas is supplied to the second fuel gas channel 50 of the third metal separator 20 through the inlet buffer part 96a.

  As shown in FIGS. 1, 4 and 6, the fuel gas moves in the direction of arrow B along the first fuel gas flow path 34 and is supplied to the anode electrode 72 of the first electrolyte membrane / electrode structure 16a. And moves in the direction of arrow B along the second fuel gas flow path 50 and is supplied to the anode electrode 72 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 oxidant gas supplied to each cathode electrode 70 and the fuel gas supplied to each anode electrode 72 are electrodes. Electricity is generated by being consumed by an electrochemical reaction in the catalyst layer.

  Next, the oxidant gas supplied and consumed to the cathode electrodes 70 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 78b and 90b. It is discharged into the hole 22b (see FIG. 1).

  The fuel gas supplied and consumed to the anode electrode 72 of the first electrolyte membrane / electrode structure 16a and the second electrolyte membrane / electrode structure 16b passes through the outlet buffer portions 84b and 96b and the discharge holes 38b and 54b. 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 32 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.

  In this case, in this embodiment, as shown in FIGS. 2 and 4, the fuel gas outlet communication hole 24a is connected to the fuel gas outlet communication hole 24a, located below the first fuel gas flow path 34 in the gravity direction and outside the power generation region 40. A first bypass channel 42 that connects the holes 24b is provided. For this reason, the water generated in the first fuel gas flow path 34 and the water jumped from the fuel gas inlet communication hole 24a circulates along the first bypass flow path 42 and passes through the outlet connection flow path 36b. It is discharged to the outlet communication hole 24b.

  At that time, the first bypass flow path 42 is formed between the first resin frame member 74 and the second metal separator 18 and is provided independently (separated) from the solid polymer electrolyte membrane 68. Yes. Therefore, even if stagnant water is generated in the first bypass flow path 42, the solid polymer electrolyte membrane 68 does not come into contact with the stagnant water. Thereby, it can prevent reliably that the solid polymer electrolyte membrane 68 deteriorates.

  In addition, the first bypass flow path 42 is provided outside the power generation region 40. For this reason, poor power supply of the fuel gas supplied to the power generation region 40 is not caused, and good power generation is reliably performed. Thereby, it is possible to obtain an effect that, with a simple configuration, stagnant water is not generated in the power generation region 40, and deterioration of the solid polymer electrolyte membrane 68 can be effectively suppressed.

  Furthermore, as shown in FIG. 4, the lower end position 36bu of the outlet connection channel 36b is disposed below the outlet lower end position 42u of the first bypass channel 42, and the bottom 24bu of the fuel gas outlet communication hole 24b. Is disposed below the lower end position 36bu of the outlet connection channel 36b. Accordingly, the water flowing along the first bypass flow path 42 is smoothly and reliably discharged from the first bypass flow path 42 through the outlet connection flow path 36b to the fuel gas outlet communication hole 24b under the action of gravity. Is done.

  In the second bypass channel 58, the same effect as that of the first bypass channel 42 can be obtained. Also, the first oxidant gas flow channel 26 and the second oxidant gas flow channel 44 may employ a bypass flow channel configured similarly to the first bypass flow channel 42 and the second bypass flow channel 58 described above. Is possible.

DESCRIPTION OF SYMBOLS 10 ... Fuel cell 12 ... Electric power generation unit 14, 18, 20 ... Metal separator 16a, 16b ... Electrolyte membrane electrode assembly 22a ... Oxidant gas inlet communication hole 22b ... Oxidant gas outlet communication hole 24a ... Fuel gas inlet communication hole 24b ... fuel gas outlet communication hole 25a ... cooling medium inlet communication hole 25b ... cooling medium outlet communication hole 26, 44 ... oxidant gas flow path 32 ... cooling medium flow path 34, 50 ... fuel gas flow path 36a, 52a ... inlet connection flow Paths 36b, 52b ... outlet connection flow path 38a, 54a ... supply hole 38b, 54b ... discharge hole 40, 56 ... power generation region 42, 58 ... bypass flow path 62, 64, 66 ... seal member 68 ... solid polymer electrolyte Membrane 70 ... Cathode electrode 72 ... Anode electrode 74, 76 ... Resin frame members 78a, 84a, 90a, 96a ... Inlet buffer portions 78b, 84b, 90b, 9 b ... outlet buffer

Claims (4)

The electrolyte membrane / electrode structure provided with a pair of electrodes on both sides of the electrolyte membrane and the separator are stacked along the horizontal direction, and the electrode surface has a vertical posture along the gravity direction. a reaction gas flow path along the electrode surfaces Ru was circulated reaction gas horizontally, the reaction gas supply passage and the reactant gas discharge circulating the reaction gas in the stacking direction of the separator and the membrane electrode assembly While the communication hole is provided, the electrolyte membrane / electrode structure is a fuel cell in which a resin frame member is integrally provided on an outer peripheral portion,
The resin frame member and the separator have an abutting portion that abuts each other and closes the lower end in the gravitational direction of the reaction gas channel at a position spaced downward from the lower end of the electrolyte membrane in the gravitational direction, Between the resin frame member and the separator, there is provided a bypass channel that is located below the contact portion in the gravitational direction and outside the power generation region, and connects the reaction gas outlet communication hole to the reaction gas outlet communication hole. A fuel cell. 2. The fuel cell according to claim 1, wherein a first reaction gas channel is formed between one side of the electrolyte membrane / electrode structure and the first separator, and the other side of the electrolyte membrane / electrode structure is formed. A second reaction gas flow path is formed between the side and the second separator,
The bypass cell is formed between the resin frame member and only one of the first separator and the second separator along the stacking direction. The fuel cell according to claim 1 or 2, wherein an inlet buffer portion is provided between the reactive gas inlet communication hole and the reactive gas flow path,
The bypass cell is connected to the reaction gas inlet communication hole via the inlet buffer portion. The fuel cell according to any one of claims 1 to 3, wherein the bypass flow path is connected to the reaction gas outlet communication hole via a connection flow path,
The fuel cell, wherein the connection channel is disposed below an outlet of the bypass channel, and a bottom portion of the reaction gas outlet communication hole is disposed below the connection channel.

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