The invention pertains to a bipolar plate in which each of the distribution channels is located facing a dividing rib of the opposite conductive sheet; and in which said distribution channels include portions of various depths that are arranged so as to form a longitudinal alternation between: an enhanced distribution zone, in which: the distribution channels have a combined cross section of a high distribution value, and the cooling channels have a combined cross section of a low cooling value; and an enhanced cooling zone, in which: the distribution channels have a combined cross section of a value that is lower than the high distribution value, and the cooling channels have a combined cross section of a value that is higher than the low cooling value.

Bipolar plate assemblies are disclosed in which the transition fuel channels are offset from the transition oxidant channels in the transition regions on the active sides of the plates. This configuration allows for a reduced pressure drop in the coolant flow in the transition regions on the inactive, coolant side of the plates and thereby improves coolant flow sharing. The assemblies are suitable for use in high power density solid polymer electrolyte fuel cell stacks.

A separator assembly for a fuel cell having an anode separator, a cathode separator, a cooling surface frame, and a gasket. In particular, the cooling surface frame is integrally bonded between peripheral portions of the anode separator and the cathode separator. Additionally, the gasket encloses the peripheral portions of the anode separator and the cathode separator between which the cooling surface frame is interposed.

Provided is a metallic material including: a base metal made of a metal; a metal compound layer stacked on a surface of the base metal, the metal compound layer mainly containing a compound of at least one transition metal in the fourth period and oxygen; a platinum group portion dispersed on a surface of the metal compound layer, the platinum group portion mainly containing at least one platinum group element; and a platinum group compound coating film which covers the platinum group portion, the platinum group compound coating film mainly containing a compound of at least one platinum group element and oxygen. The at least one platinum group element contained in the platinum group portion is preferably one or more of Ru, Rh, Os, and Ir.

Provided is a metallic material including: a base metal made of a metal; a metal compound layer stacked on a surface of the base metal, the metal compound layer mainly containing a compound of at least one transition metal in the fourth period and oxygen; a platinum group portion dispersed on a surface of the metal compound layer, the platinum group portion mainly containing at least one platinum group element; and a platinum group compound coating film which covers the platinum group portion, the platinum group compound coating film mainly containing a compound of at least one platinum group element and oxygen. The at least one platinum group element contained in the platinum group portion is preferably one or more of Ru, Rh, Os, and Ir.

In a fuel cell separator comprising gas flow channels composed of a plurality of concavoconvex parts in the center region and flat parts on the periphery of the gas flow channels, the fuel cell separator provided with the first bent parts that bend approximately vertically to the same direction respectively at both edge parts at least in one direction among on flat parts in both directions of gas flow channels, and the second bent parts between gas flow channel-side flat parts and edge-side flat parts on the flat parts in the inward from the first bent parts on both sides with a smoothly curved cross-sectional shape of the gas flow channel-side bent ends of the second bent parts, and the production method thereof.

A separator for a fuel cell includes a thin metal plate, protrusions that are formed on the metal plate to be close to each other, and gas passages formed by the protrusions. Each gas passage has a first opening corresponding to an inlet and a second opening corresponding to an outlet. The gas passages include a first gas passage, which has a relatively low pressure loss of gas flow, and a second gas passage, which has a relatively high pressure loss of gas flow. The area of the first opening of the first gas passage is set to be smaller than the area of the first opening of the second gas passage.

A separator for a fuel cell includes a thin metal plate, protrusions that are formed on the metal plate to be close to each other, and gas passages formed by the protrusions. Each gas passage has a first opening corresponding to an inlet and a second opening corresponding to an outlet. The gas passages include a first gas passage, which has a relatively low pressure loss of gas flow, and a second gas passage, which has a relatively high pressure loss of gas flow. The area of the first opening of the first gas passage is set to be smaller than the area of the first opening of the second gas passage.

A separator assembly used for a fuel cell includes one pair of metal separators joined together and including a bead seal section including one pair of seal bead portions projecting in opposite directions respectively, an elastic body disposed in the bead seal section, and a first communication hole which extends through the separator assembly in a thickness direction of the separator assembly and which allows a reaction gas or a coolant to flow through the separator assembly. The bead seal section is disposed along an outer periphery of the separator assembly and along a shape of the first communication hole. The elastic body of a predetermined length is disposed in the bead seal section.

A separator assembly used for a fuel cell includes one pair of metal separators joined together and including a bead seal section including one pair of seal bead portions projecting in opposite directions respectively, an elastic body disposed in the bead seal section, and a first communication hole which extends through the separator assembly in a thickness direction of the separator assembly and which allows a reaction gas or a coolant to flow through the separator assembly. The bead seal section is disposed along an outer periphery of the separator assembly and along a shape of the first communication hole. The elastic body of a predetermined length is disposed in the bead seal section.