Patent ID: 8241816

Claim:
A separator of a fuel cell stack, comprising a first-electrode plate having a flat surface that faces a first electrode of a membrane electrode assembly that adjoins the first-electrode plate; a second-electrode plate having a flat surface that faces a second electrode of a membrane electrode assembly that adjoins the second-electrode plate; and an intermediate plate sandwiched between the first-electrode plate and the second-electrode plate, wherein: a reactant gas supply manifold and a reactant gas exhaust manifold are formed in the separator so as to penetrate the thicknesses of the first-electrode plate, the second-electrode plate and the intermediate plate, the intermediate plate has a plurality of reactant gas supply channel openings which penetrate the thickness of the intermediate plate and form a plurality of reactant gas supply channels, each of which communicates at one end thereof with the reactant gas supply manifold, and reaches, at the other end thereof, a first end portion of an active region, the intermediate plate further has a plurality of reactant gas exhaust channel openings which penetrate the thickness of the intermediate plate and form a plurality of reactant gas exhaust channels, each of which communicates at one end thereof with the reactant gas exhaust manifold, and reaches, at the other end thereof, a second end portion of the active region, the first-electrode plate has a plurality of reactant gas supply holes which penetrate the thickness of the first-electrode plate and are aligned to communicate with the other ends of each of the reactant gas supply channels, and a plurality of reactant gas exhaust holes which penetrate the thickness of the first-electrode plate and are aligned to communicate with the other ends of each of the reactant gas exhaust channels, the reactant gas supply channels are arranged at a first channel spacing, the reactant gas exhaust channels are arranged at a second channel spacing, the first channel spacing is smaller than the second channel spacing, and a length of each of the first channel spacing between adjacent reactant gas supply channels is identical, the reactant gas supply channels have a first channel width and the reactant gas exhaust channels have a second channel width, the second channel width is larger than the first channel width, and the reactant gas supply channels are arranged over substantially a same width as the reactant gas supply manifold.