NOVELTY - A fuel cell stack is provided with fuels cells having an active area and a circumference ratio extending to the corresponding ratio of a square active area. The circumference and the active area is defined by the geometrical shape of the active area. Cooling layers project beyond the circumferential outer periphery of a laminate to form inner active section and peripheral cooling fin areas.    USE - For use as a fuel cell stack for vehicle.    ADVANTAGE - The stack has improved ratio of heat dissipation ability to the heat generation in the active area while using thin and lightweight and limitedly large heat conducting layers. The cooling system is inexpensive, lightweight, compact, and conducts all the waste heat of the reaction process out of the fuel cell stack.    DETAILED DESCRIPTION - A fuel cell stack comprises fuel cells electrically connected in series and having equivalent active section areas (15) and circumferences; end and separator plates delimiting each cell; and cooling layers (9), each projecting beyond the circumferential outer periphery of the laminate of the other layers to form an inner active section area and a peripheral cooling fin (11) area. The fuel cell comprises a laminate of layers of electrolyte membrane and catalyst, and electrode and gas diffusion layers having functions that can be combined with multifunction layers. The function of the cooling layers may also be combined with other multifunction layers. The ratio of circumference (14) and active area of the stack, which is defined by the geometrical shape of the active area, extends the corresponding ratio of a square active area.    An INDEPENDENT CLAIM is also included for the use of expanded graphite material for a bipolar plate, an electrode, and a gas diffusion layer of a fuel cell.    DESCRIPTION OF DRAWING(S) - The figure shows a diagrammatic plan view of the cooling fin with gas channels.    Cooling layers (9)    Cooling fin (11)    Circumference (14)    Active section areas (15)    Length (16)