Patent ID: 8053125

Claim:
A fuel cell comprising: an electrolyte electrode assembly stacked between a pair of metal separators in a stacking direction, said electrolyte electrode assembly including a pair of electrodes and an electrolyte interposed between said electrodes; a reactant gas passage and a coolant passage extending through said metal separators in the stacking direction; a reaction surface provided on each of said metal separators facing said electrolyte electrode assembly; a cooling surface provided on each of said metal separators opposite to said reaction surface; a reactant gas flow field provided on said reaction surface of said metal separator for supplying a reactant gas along an electrode reaction surface of said electrolyte electrode assembly, the reaction surface including reactant buffers connecting the reactant gas passage to the reactant gas flow field on the reaction surface; a coolant flow field provided between said metal separators on said cooling surface for supplying a coolant along said metal separators; a buffer connecting said coolant passage and said coolant flow field, the buffer provided on said cooling surface of said metal separator; and a seal member disposed integrally on at least said cooling surface to cover all portions of said cooling surface except a region corresponding to said reaction surface facing said electrode reaction surface and except a region of said buffer connecting said coolant passage and said coolant flow field and a region corresponding to the reactant buffers on the reaction surface, the coolant flowing on the cooling surface only through a region where the seal member is not disposed, the seal member including expansion regions located immediately adjacent to sides of the coolant flow field and between the coolant flow field and the coolant passage.