Patent ID: 7405019
Filing Date: 2008-07-29
Classification: H01M,Y02E

Abstract:
1. A polymer electrolyte fuel cell comprising: a membrane electrode assembly forming a cell comprising a hydrogen-ion conductive polymer electrolyte membrane and an anode and a cathode sandwiching said polymer electrolyte membrane, each of said anode and said cathode being positioned in a substantially central part of said polymer electrolyte membrane; an anode-side separator plate having a pair of fuel gas manifold apertures, a pair of oxidant gas manifold apertures, and a fuel gas flow channel connected to said pair of fuel gas manifold apertures for supplying and discharging a fuel gas to and from the anode; a cathode-side separator plate having a pair of fuel gas manifold apertures, a pair of oxidant gas manifold apertures, and an oxidant gas flow channel connected to said pair of oxidant gas manifold apertures for supplying and discharging an oxidant gas to and from the cathode; an anode-side sealing member provided on the anode-side surface of said anode-side separator plate; and a cathode-side sealing member provided on the cathode-side surface of said cathode-side separator plate, wherein: said membrane electrode assembly is sandwiched under pressure between said anode-side and cathode-side separator plates to form said cell, said anode-side sealing member and said cathode-side sealing member seal the cell, in cooperation with the polymer electrolyte membrane, at sealing parts where the anode-side and cathode-side sealing members are opposed to each other, to prevent the fuel gas and the oxidant gas from leaking out of said fuel gas flow channel and said oxidant gas flow channel, said fuel gas flow channel being positioned in a substantially central part of the separator plate, said pair of fuel gas manifold apertures and said pair of oxidant gas manifold apertures being positioned in outer parts of the separator plate relative to said fuel gas flow channel, said oxidant gas flow channel being positioned in a substantially central part of the separator plate, said pair of fuel gas manifold apertures and said pair of oxidant gas manifold apertures being positioned in outer parts of the separator plate relative to said oxidant gas flow channel, said polymer electrolyte membrane is large enough to cover the anode and the cathode but the edge of said polymer electrolyte membrane does not reach said fuel and oxidant gas manifold apertures, said anode-side sealing member has a first anode-side sealing section that surrounds the anode and the fuel gas manifold apertures to form a closed loop and a second anode-side sealing section that surrounds said polymer electrolyte membrane in combination with said first anode-side sealing section, said first anode-side sealing section being in contact with said polymer electrolyte membrane at the part surrounding the anode, said cathode-side sealing member has a first cathode-side sealing section that surrounds the cathode and the oxidant gas manifold apertures to form a closed loop and a second cathode-side sealing section that surrounds said polymer electrolyte membrane in combination with said first cathode-side sealing section, said first cathode-side sealing section being in contact with said polymer electrolyte membrane at the part surrounding the cathode, said anode-side and cathode-side sealing sections substantially correspond in position, and said anode-side and cathode-side sealing members are sandwiched between said anode-side and cathode-side separator plates and pressed against each other or the polymer electrolyte membrane at the respective sealing sections, and at the pressed parts, one of said sealing members has a pointed rib that comes in contact with said polymer electrolyte membrane or the other sealing member in a linear manner, and the other sealing member comes in contact with said polymer electrolyte membrane or said one sealing member surface to surface.