Patent ID: 7201990

Claim:
A fuel cell stack comprising a stack of sub-stacks with intermediate plates interposed therebetween, each of the sub-stacks comprising a stack of membrane electrode assemblies with separators interposed therebetween, each comprising an anode, a cathode, and an ion exchange membrane sandwiched between the anode and the cathode, wherein said sub-stacks constitute an inner manifold in which a reactant gas inlet communication passage and a reactant gas outlet communication passage respectively penetrate straight through said stack of sub-stacks in the stacking direction, said inner manifold allowing the reactant gas to flow in straight paths through said reactant gas inlet communication passage and said reactant gas outlet communication passage, as well as in paths branching from said reactant gas inlet communication passage and said reactant gas outlet communication passage and extending between said separators and said membrane electrode assemblies, wherein said reactant gas inlet communication passage of an upstream sub-stack is in alignment with said reactant gas inlet communication passage of a downstream sub-stack in the stacking direction, and said reactant gas outlet communication passage of said upstream sub-stack is in alignment with said reactant gas outlet communication passage of said downstream sub-stack in the stacking direction, and wherein each of said intermediate plates has an interconnecting passage for interconnecting said reactant gas outlet communication passage of said upstream sub-stack and said reactant gas inlet communication passage of said downstream sub-stack, with respect to a direction in which said reactant gas is supplied.