Abstract: The invention relates to a modified planar cell with a solid-oxide solid electrolyte, a gas-diffuse anode, a cathode, a metal or oxide current path and a current-gas supply. The supporting solid electrolyte of the cell is in the form of a corrugated plate consisting of corrugations. In cross-section, the corrugations of the plate constitute an isosceles, identical-height trapezium, without a larger lower base with holes. The holes are formed on one side in the upper part of each corrugation, for supplying one of the reagents, e.g. fuel in case of a fuel cell. The corrugations are connected to one another at their base in order to form gas space channels of the cell. The gas space channels are in the form of inverted isosceles trapezia without a larger upper base and the angle ? at their smaller base is 0.1 to 89.9°. The corrugated plate is connected to two opposing walls, a front wall and a rear wall.