Patent ID: 6893759

Claim:
A polymer electrolyte fuel cell stack comprising a plurality of unit cell main components juxtaposed in the same direction and electrically connected in series with each other, each unit cell main component comprising: a membrane electrode assembly including a proton exchange membrane, and a fuel electrode and oxidizer electrode placed on opposing plate surfaces of the proton exchange membrane; a separator including a plurality of first reactant gas flow paths to supply a first reactant gas, formed substantially linearly in a vertical direction in a first plate surface to be brought into contact with one of the fuel electrode and the oxidizer electrode, and a plurality of second reactant gas flow paths to supply a second reactant gas, formed in a second plate surface of the separator; and water supply means for cooling the unit cell main component by a latent heat system by supplying water to the first reactant gas flow paths, the water supply means including a manifold formed in the vertical direction to extend through the separator, a first water supply path positioned, in the surface in which the second reactant gas flow path is formed, above a lowermost portion in the vertical direction of the manifold, and continuously formed in a horizontal direction, a plurality of through holes formed with a predetermined spacing from the first water supply path so as to communicate with the first reactant gas flow paths, and a plurality of second water supply flow paths which are formed between the through holes and the first water supply path so as to allow the through holes to communicate with the first water supply path, and which guide water in the first water supply path to the through holes.