Abstract: A decrease in voltage in a polymer electrolyte fuel cell comprising stack of unit cells caused by the temperature difference between the cells located at the ends and the other cells due to a differential in heat dissipation from end plates is prevented by controlling the cooling temperature of the cells closest to the end plates of the fuel cell without affecting the output voltage of the cells in the middle by not including a coolant flow channel in the conductive separator plate between at least one of the end plates and the unit cell located closest to the one of the end plates.

Abstract: A polymer electrolyte fuel cell of the present invention includes conductive separator plates comprising molded plates of a composition comprising a binder, conductive carbon particles whose average particle diameter is not less than 50 ?m and not more than ? of the thickness of the thinnest portion of the conductive separator plate, and at least one of conductive carbon fine particles and micro-diameter carbon fibers. The separator plates do not require conventional cutting processes for gas flow channels, etc., and can be easily mass produced by injection molding and achieve a reduction in the cost.

Abstract: A decrease in voltage in a polymer electrolyte fuel cell comprising stack of unit cells caused by the temperature difference between the cells located at the ends and the other cells due to a differential in heat dissipation from end plates is prevented by controlling the cooling temperature of the cells closest to the end plates of the fuel cell without affecting the output voltage of the cells in the middle by not including a coolant flow channel in the conductive separator plate between at least one of the end plates and the unit cell located closest to the one of the end plates.

Abstract: A polymer electrolyte fuel cell of the present invention includes a hydrogen ion-conductive polymer electrolyte membrane, an anode and a cathode sandwiching the hydrogen ion-conductive polymer electrolyte membrane, an anode-side conductive separator plate having a gas flow channel for supplying a fuel gas to the anode, and a cathode-side conductive separator plate having a gas flow channel for supplying an oxidant gas to the cathode.

Abstract: A polymer electrolyte fuel cell comprising: a plurality of conductive separator plates, each comprising a corrugated metal plate; an electrolyte membrane-electrode assembly inserted between the separator plates, the electrolyte membrane-electrode assembly including a hydrogen-ion conductive polymer electrolyte membrane having its periphery covered with a gasket, an anode attached to one side of the electrolyte membrane, and a cathode attached to the other side of the electrolyte membrane; and gas charge and discharge device for charging and discharging a fuel gas and an oxidant gas to and from the anode and the cathode, respectively, wherein the gas charge and discharge device charges and discharges the fuel gas to and from the anode through the grooves on one side of the corrugated metal plate and charges and discharges the oxidant gas to and from the cathode through the grooves on the other side of the corrugated metal plate.

Abstract: A decrease in voltage in a polymer electrolyte fuel cell comprising stack of unit cells caused by the temperature difference between the cells located at the ends and the other cells due to a differential in heat dissipation from end plates is prevented by controlling the cooling temperature of the cells closest to the end plates of the fuel cell without affecting the output voltage of the cells in the middle by not including a coolant flow channel in the conductive separator plate between at least one of the end plates and the unit cell located closest to the one of the end plates.

Abstract: A fuel cell including a cell stack including plural electrically conductive separator plates and MEAs (electrolyte membrane-electrode assemblies) inserted among the separator plates. The fuel cell further includes gas communication grooves, where the gas communication grooves on one main surface of each separator plate are positioned to correspond to the ribs on the other main surface thereof, whereby thin wall portions in the separator plate can be avoided as much as possible, thereby to solve above described problems.

Abstract: A conductive separator plate for a polymer electrolyte fuel cell is disclosed which includes a cell stack and a plurality of conductive separator plates, the conductive separator plates being formed of a carbon powder and a binder, the conductive separator plates having a main portion which is raised from a peripheral portion surrounding the main portion, the main portion being in contact with an anode or cathode of the fuel cell and being provided with a gas flow path for supplying a fuel gas to the anode or a gas flow path for supplying an oxidant gas to the cathode.

Abstract: The present invention relates to a polymer electrolyte fuel cell comprising: an electrolyte membrane-electrode assembly including an anode, a cathode and a polymer electrolyte membrane interposed therebetween; an anode-side conductive separator plate having a gas flow channel for supplying a fuel gas to the anode; and a cathode-side conductive separator plate having a gas flow channel for supplying an oxidant gas to the cathode. A conductive separator plate made of carbon has poor wettability with water. This has posed the disadvantage that variations in performance are induced by nonuniform gas distribution among cells due to the accumulation of product water or humidifying water in the gas flow channel on the surface of the separator plate. The present invention employs a conductive separator plate comprising a conductive carbon having a hydrophilic functional group, at least in a portion of the gas flow channels, thereby preventing water from accumulating in the gas flow channels.

Abstract: A decrease in voltage in a polymer electrolyte fuel cell comprising stack of unit cells caused by the temperature difference between the cells located at the ends and the other cells due to a differential in heat dissipation from end plates is prevented by controlling the cooling temperature of the cells closest to the end plates of the fuel cell without affecting the output voltage of the cells in the middle by not including a coolant flow channel in the conductive separator plate between at least one of the end plates and the unit cell located closest to the one of the end plates.

Abstract: The present invention relates to a fuel cell comprising a cell stack including plural electrically conductive separator plates and MEAs (electrolyte membrane-electrode assemblies) inserted among the separator plates, more particularly to improvements of the separator plates. Conventionally, fuel gas communication grooves and oxidant gas communication grooves were formed on the front and the rear main surfaces of each separator plate, respectively, so that both gas communication grooves are positioned to correspond to each other. Accordingly, when it was attempted to make the fuel cell smaller in size, the groove bottom portions between both gas communication grooves in each separator plate became more thin-walled. This brought about consequential problems of e.g. gas leakage due to fractures of the thin wall portions and difficulty in molding the thin wall portions.

Abstract: End plates, as constituting elements in a fuel cell, are conventionally made by cutting metal plates. Therefore, they have problems in that it is difficult to reduce their cost, and they are inconveniently heavy, and that they are likely to be corroded by supplied gases and cooling water since they contact such gases and water at inside surfaces of manifold holes of the metal end plates.

Abstract: A conductive separator plate for a polymer electrolyte fuel cell which comprises a cell stack comprising a plurality of membrane electrode assemblies and a plurality of conductive separator plates that are stacked alternately, each of the membrane electrode assemblies comprising a hydrogen-ion conductive polymer electrolyte membrane, and an anode and a cathode sandwiching the polymer electrolyte membrane, the conductive separator plate being formed of a molded plate comprising a carbon powder and a binder, the conductive separator plate having a main portion which is raised from a peripheral portion surrounding the main portion, the main portion being in contact with the anode or the cathode and being provided with a gas flow path for supplying a fuel gas to the anode or a gas flow path for supplying an oxidant gas to the cathode.

Abstract: A polymer electrolyte fuel cell of the present invention includes a hydrogen ion-conductive polymer electrolyte membrane, an anode and a cathode sandwiching the hydrogen ion-conductive polymer electrolyte membrane, an anode-side conductive separator plate having a gas flow channel for supplying a fuel gas to the anode, and a cathode-side conductive separator plate having a gas flow channel for supplying an oxidant gas to the cathode.

Abstract: A method of producing a fuel cell comprising the steps of: (A) molding a separator having a gas flow channel or a cooling water flow channel by injection molding process having a step of injecting a mixture comprising one or more conductive inorganic materials and one or more resins into a mold; (B) producing an assembly comprising an electrolyte and a pair of electrodes sandwiching the electrolyte; and (C) combining the separator with the assembly to produce a fuel cell.