Fuel cell stack

Abstract

To prevent the flooding phenomenon at the cathode in a unit cell where the temperature is relatively low or the supply of air is small, a fuel cell stack includes at least three flat unit cells stacked with separators interposed therebetween, the unit cells comprising an anode, a cathode and an electrolyte membrane sandwiched therebetween, and having an oxidant channel formed on the surface of the separator adjacent to the cathode, and the anode and the cathode comprising a catalyst layer attached to the electrolyte membrane and a diffusion layer, wherein the cross-sectional area of the inlet side of the oxidant channel, the area of the cathode catalyst layer, the thickness of the electrolyte membrane or the amount of a water repellent contained in the combination of the cathode and the oxidant channel is the largest in at least one of the unit cells at the ends of the stack.

Dependencies are inferred from the claim text.