The invention provides gasket for a fuel battery provided in a fuel battery cell in which an intermediate part including an MEA is interposed between a pair of separators, and structured such that each of a gasket main body retained to one separator of the pair of separators and a gasket main body retained to the other separator comes into contact with the intermediate part at positions where they overlap planarly, wherein bank portions for fixed size stop according to a gasket thickness are integrally formed in both sides or one side in a width direction of both the gasket main bodies. The bank portions for fixed size stop are preferably supported by convex portions which are provided in the separators. Therefore, it is possible to inhibit gasket main bodies from being compressed beyond supposition in the case that contact portions of the gasket main bodies are compressed.

A relation of X×ΔT×CTE.sub.t<L×t is satisfied, where X represents a distance between a circumferentially innermost position of a bonded portion of a resin frame bonded to first projections of separators and a circumferentially inner end of the resin frame; L represents a distance between the circumferentially inner end of the resin frame and a circumferentially outermost position of a held portion of a membrane electrode gas-diffusion-layer assembly that is interposed and held between second projections of the separators: ΔT represents a temperature difference from a low temperature T1 of −40° C. to a high temperature T2 of 100° C. CTE.sub.f represents an average coefficient of linear expansion of the resin frame within a range of the low temperature T1 to the high temperature T2; t represents a breaking elongation of the electrolyte membrane at the low temperature T1; and the distances X, L represents dimensions at the high temperature T2.

A relation of X×ΔT×CTE.sub.t<L×t is satisfied, where X represents a distance between a circumferentially innermost position of a bonded portion of a resin frame bonded to first projections of separators and a circumferentially inner end of the resin frame; L represents a distance between the circumferentially inner end of the resin frame and a circumferentially outermost position of a held portion of a membrane electrode gas-diffusion-layer assembly that is interposed and held between second projections of the separators: ΔT represents a temperature difference from a low temperature T1 of −40° C. to a high temperature T2 of 100° C. CTE.sub.f represents an average coefficient of linear expansion of the resin frame within a range of the low temperature T1 to the high temperature T2; t represents a breaking elongation of the electrolyte membrane at the low temperature T1; and the distances X, L represents dimensions at the high temperature T2.

Provided is an air-cooled fuel cell system, wherein the air-cooled fuel cell system comprises a fuel cell, an oxidant gas system and a cooling gas system; wherein the fuel cell comprises a fuel cell stack comprising stacked unit fuel cells; wherein each of the unit fuel cells comprises a cathode separator having an oxidant gas flow path in a wavy plate form, a membrane electrode gas diffusion layer assembly, an anode separator having a fuel gas flow path in a wavy plate form, and a cooling fin having a cooling gas flow path in a wavy plate form; and wherein the air-cooled fuel cell system has a cooling ability distribution in an oxidant gas flow direction of the oxidant gas flow path.

Provided is an air-cooled fuel cell system, wherein the air-cooled fuel cell system comprises a fuel cell, an oxidant gas system and a cooling gas system; wherein the fuel cell comprises a fuel cell stack comprising stacked unit fuel cells; wherein each of the unit fuel cells comprises a cathode separator having an oxidant gas flow path in a wavy plate form, a membrane electrode gas diffusion layer assembly, an anode separator having a fuel gas flow path in a wavy plate form, and a cooling fin having a cooling gas flow path in a wavy plate form; and wherein the air-cooled fuel cell system has a cooling ability distribution in an oxidant gas flow direction of the oxidant gas flow path.

An end plate includes a plate body, fastening portions, and ribs. The plate body is rectangular and includes two long sides and two short sides. The plate body is arranged on an end of a cell stack of a fuel cell. The fastening portions are fastened to a case containing the cell stack. The fastening portions extend along edges of the plate body. The ribs are arranged in a grid-like manner on the plate body surrounded by the fastening portions. The ribs are arranged so that recesses defined between the ribs each have a quadrilateral shape in which two diagonals have different lengths. The ribs are arranged so that the recesses extend in a direction in which the ribs extend and so that a longer one of the two diagonals of each of the recesses extends parallel to the short sides of the plate body.

An end plate includes a plate body, fastening portions, and ribs. The plate body is rectangular and includes two long sides and two short sides. The plate body is arranged on an end of a cell stack of a fuel cell. The fastening portions are fastened to a case containing the cell stack. The fastening portions extend along edges of the plate body. The ribs are arranged in a grid-like manner on the plate body surrounded by the fastening portions. The ribs are arranged so that recesses defined between the ribs each have a quadrilateral shape in which two diagonals have different lengths. The ribs are arranged so that the recesses extend in a direction in which the ribs extend and so that a longer one of the two diagonals of each of the recesses extends parallel to the short sides of the plate body.

A gas channel forming plate is arranged between a membrane electrode assembly and a flat separator base. The gas channel forming plate includes gas channels arranged on a surface that faces the membrane electrode assembly, water channels each formed on the back side of the protrusion between an adjacent pair of the gas channels, communication passages that connect the gas channels and the water channels to each other, and guide portions formed by causing an inner wall surface of a gas channel to protrude inward in the gas channel. The guide portions are formed such that the upstream edge of each communication passage is arranged in a range in which, in the velocity vector of the gas flowing in the gas channel, the directional component directed from the side corresponding to the membrane electrode assembly toward the flat separator base has a positive value.

A gas channel forming plate is arranged between a membrane electrode assembly and a flat separator base. The gas channel forming plate includes gas channels arranged on a surface that faces the membrane electrode assembly, water channels each formed on the back side of the protrusion between an adjacent pair of the gas channels, communication passages that connect the gas channels and the water channels to each other, and guide portions formed by causing an inner wall surface of a gas channel to protrude inward in the gas channel. The guide portions are formed such that the upstream edge of each communication passage is arranged in a range in which, in the velocity vector of the gas flowing in the gas channel, the directional component directed from the side corresponding to the membrane electrode assembly toward the flat separator base has a positive value.

This disclosure provides a manufacturing method for manufacturing a fuel cell separator. The manufacturing method includes: providing a material sheet including a fiber sheet, carbon particles, and a resin, the carbon particles and the resin being applied to the fiber sheet; and pressing the material sheet into a recess-projection shape by which a gas circulation passage is to be formed, and forming a top portion and a shift portion. In the pressing of the material sheet, the material sheet is pressed such that a draft of the top portion is higher than a draft of the shift portion.