OPERATION METHOD OF FUEL CELL, FUEL CELL SYSTEM AND OPERATION METHOD THEREOF TO MAINTAIN HIGH GENERATION VOLTAGE FOR A LONG TIME AND TO PREVENT DETERIORATION OF FUEL CELL EVEN WHEN FUEL CELL IS STOPPED REPEATEDLY

摘要

PURPOSE: A method for operating a fuel cell, a fuel cell system and its operation method are provided, to inhibit the deterioration due to the oxidation and reduction of a cathode by controlling the potential of a cathode within a certain range when the generation of a fuel cell is stopped, thereby improving durability. CONSTITUTION: The operation method of a fuel cell provided with an electrolyte, an anode and a cathode having a metal catalyst inserting the electrolyte, and a pair of separator plates having a gas channel for supplying and discharging a fuel gas to the anode and for supplying and discharging an oxidant gas to the cathode, comprises the step of lowering the potential of a cathode when the voltage of a fuel cell is lowered below a critical voltage or after a certain time is passed from the prior operation. Also the operation method comprises the step of lowering the potential of the cathode of a specific one or a plurality of cells and lowering the potential of the cathodes of other cells in turns after the voltage of the cell is re-risen.