Polymer electrolyte fuel cell

A polymer electrolyte fuel cell comprising:

• two or more membrane-electrode assemblies having a hydrogen ion conductive polymer electrolyte membrane, and an anode and a cathode sandwiching said polymer electrolyte membrane;
• and two or more separator plates stacked alternately with said membrane-electrode assemblies, each of said anode and said cathode having a gas diffusion layer and a catalyst layer contacting said polymer electrolyte membrane,
• wherein at least one of said separator plates is a composite separator plate comprising a combination of an anode side separator plate and a cathode side separator plate,
• each of said anode side separator plate and said cathode side separator plate includes a main surface portion entirely contacting said anode and said cathode, and a peripheral edge portion, said peripheral edge portion being formed to be flat,
• said main surface portions have a convex shape protruding toward said anode side and said cathode side respectively, and have a gas flow path for supplying a fuel gas and an oxidant gas to said anode and said cathode respectively,
• a thickness of at least one of said anode side separator plate and said cathode side separator plate increases or decreases in proportion to the shapes of the said main surface portion's protrusions;
• the surface of said main surface portion is formed so that a cross section perpendicular to said main surface portion draws a curve, the center of said main surface portion being the highest and the height gradually decreases toward said peripheral edge portion, said curve has an infection point;
• and
• an average thickness of said main surface portion is thicker than an average thickness of said peripheral edge portion, and a difference Δt between a thickness of the thickest portion of said main surface portion and an average thickness of said peripheral edge portion is 5-30 μm.