Abstract: A fuel cell stack comprises membrane electrode assemblies (3) in which gas diffusion electrodes (2a,2b) are arranged on both sides of an ion exchange membrane (1) and a reactant gas supply separators (5) interposed between the membrane electrode assemblies (3). The reactant gas supply separators (5) each has a first surface having first reactant gas supply grooves (9a) for supplying first reactant gas, a second surface having second reactant gas supply grooves (9b) for supplying an second reactant gas, and water supply means for supplying water to the first reactant gas supply grooves (9a). The water supply means has a water supply grooves (15) for introducing water from a water supply manifold (14) disposed on the second surface, communication holes (16) for communication of the second surface with the first surface, and a buffer section (17) having a porous body (20) for uniformly distributing water from the water supply grooves (15) to the communication holes (16).

Abstract: A method of manufacturing a fuel cell assembly, said assembly comprising at least one unit cell, said unit cell comprising at least two planar electrodes, said electrodes being ribbed on one side thereof and having a catalyst layer on the second side thereof, and a matrix impregnated with an electrolyte, comprising the steps of:arranging said electrolytes on each side of said matrix with said second side of each said electrode in contact with said matrix; andpolarizing the potential of at least one electrode in one of the positive and negative directions by applying a potential from an external source.