Abstract: A fuel cell stack having stacked unit fuel cells, each having a pair of separators between which a membrane electrode assembly is provided, which includes an anode and a cathode. Each separator has protruding lines arranged vertically in a zigzag manner, which protrude in a direction going away from the membrane electrode assembly. A space between the anode and the protruding lines of the separator facing the anode is used as a fuel gas passage. A space between the cathode and the protruding lines of the separator facing the cathode is used as an oxidant gas passage. At least part of the separators are each arranged in close contact with another separator so that a coolant passage through which a coolant flows horizontally is formed between both separators. A lower area of the coolant passage has a larger flow resistance than that of an upper area thereof.

Abstract: A fuel cell stack having stacked unit fuel cells, each having a pair of separators between which a membrane electrode assembly is provided, which includes an anode and a cathode. Each separator has protruding lines arranged vertically in a zigzag manner, which protrude in a direction going away from the membrane electrode assembly. A space between the anode and the protruding lines of the separator facing the anode is used as a fuel gas passage. A space between the cathode and the protruding lines of the separator facing the cathode is used as an oxidant gas passage. At least part of the separators are each arranged in close contact with another separator so that a coolant passage through which a coolant flows horizontally is formed between both separators. A lower area of the coolant passage has a larger flow resistance than that of an upper area thereof.

Abstract: A metal separator for fuel cells includes: a plate which is corrosion resistant; conductive inclusions projecting at a surface of the plate; a gold covering layer formed above the conductive inclusions; and a compound layer formed between the conductive inclusions and the gold covering layer, the compound layer composed of a component of the conductive inclusions and gold.

Abstract: A metallic separator for a fuel cell (and a manufacturing method therefore) can reduce damage to an electrode assembly, open up the maximum capacity of the reducing effect of contact resistance due to coating of gold by gold plating or the like, and reduce consumption of gold to lower the cost. Conductive inclusions are exposed at the surface with corrosion resistance, and at least one kind of metal or an alloy thereof selected from silver, copper, nickel, and tin is precipitated on the exposed conductive inclusions. From the viewpoint of reducing contact resistance, the conductive inclusions preferably protrude from the separator surface.