Fuel Cell Separator

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 thereof that corresponds to the membrane electrode assembly;
• 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 that is opposed to the first end portion thereof;
• the first-electrode plate has at least one reaction gas supply hole which penetrates the thickness of the first-electrode plate and communicates with the other ends of the reactant gas supply channels, and at least one reaction gas exhaust hole which penetrates the thickness of the first-electrode plate and communicates with the other ends of the reactant gas exhaust channels;
• and wherein
• the reactant gas supply channels and the reactant gas exhaust channels are arranged alternately such that the respective reactant gas supply channels are not aligned with the respective reactant gas exhaust holes in a direction in which an array of the reactant gas supply channels and an array of the reactant gas exhaust channels are opposed to each other.