In a polymer electrolyte fuel cell stack using a latent heat cooling system, a
plurality of first reactant gas flow paths formed in one plate surface of each
separator are made substantially linear in the vertical direction, and an arrangement
capable of supplying water to the first reactant gas flow paths includes a water
manifold formed to extend through the separator, a water supply path branched from
the water manifold and horizontally formed in a surface in which second reactant
gas flow paths are formed, and communication holes horizontally formed in a first
reactant gas flow path introducing portion to allow the water supply path to communicate
with the first reactant gas flow paths, and present above the lowermost portion
in the vertical direction of the water manifold. With this arrangement, stable
power generation can be performed regardless of, e.g., the stack installation angle
or vibrations.
