Abstract: A conventional fuel cell comprises a plurality of cell elements stacked via separator plates, each cell element comprising an electrolyte plate, and cathode and an anode which sandwich the electrolyte plate. A power generation part of the fuel cell is defined by the electrolyte plate, cathode and an anode. Oxidizing gas and fuel gas are supplied to each cell element in the same direction but the direction is opposite the gas flow of an adjacent cell element. In the improvement, preheating devices are provided next to the power generation part as a part of the fuel cell in the direction gases flow, in a manner such that both incoming and outgoing gases pass through the preheating device. The preheating device includes a plurality of heat exchange promoting elements in the form of projections provided on both faces of the separator plate.

Abstract: Cell elements, each of which includes electrolyte plate such as fused carbonate, an anode plate and a cathode plate, and separator plates provided with heat transfer assisting means are piled up one after the other. Oxidizer gas supplied to one separator plate flows in the direction opposite to the oxidizer gas supplied to an adjacent separator plate, so that heat propagates easily in the direction the cell elements and the separator plates are piled up through the heat transfer assisting means, making the temperature profile of the fuel cell more gentle.