Patent ID: 8053140

Claim:
A polymer electrolyte fuel cell comprising: a membrane electrode assembly including a polymer electrolyte membrane and a pair of catalyst electrodes sandwiching the polymer electrolyte membrane; a pair of separators that sandwich the membrane electrode assembly, the separators each including linear reaction gas channels defined by linear channel ribs, a reaction gas supply manifold hole, and a reaction gas discharge manifold hole; and an inlet gas distributor that connects the reaction gas supply manifold hole and the reaction gas channels, wherein the inlet gas distributor includes n distribution ribs for partitioning the inlet gas distributor into a plurality of spaces, n being an integer equal to or greater than 2, the distribution ribs each having a longitudinal axis perpendicular to a longitudinal axis of the linear reaction gas channels, the distribution ribs each having at least two slits provided therein, the slits extending in parallel to the longitudinal axis of the linear reaction channels, when, of the distribution ribs, a distribution rib positioned closest to the reaction gas supply manifold hole is considered a first distribution rib and the distribution rib positioned closest to the reaction gas channels an n-th distribution rib, and when, of the spaces, a space positioned between the first distribution rib and the reaction gas supply manifold hole is considered as a diffusion space, an average of sectional areas of the diffusion space, the sectional areas taken along the longitudinal axis of the reaction gas channel and along a normal to the surface of the separator, is larger than a sectional area of any of the slits of the first distribution rib, the sectional area taken along the longitudinal axis of the distribution rib and along a normal to the surface of the separator, and slits of an m-th distribution rib are positioned at midpoints between adjacent slits of an (m+1)-th distribution rib, m being an integer between 1 and n−1.