Patent ID: 7968238
Filing Date: 2011-06-28
Classification: H01M,Y02E

Abstract:
1. A method for operating a fuel cell system, the fuel cell system comprising: a fuel cell stack comprising a plurality of cells connected in series, each cell comprising an anode, a cathode, and an electrolyte membrane interposed between the anode and the cathode, the anode and the cathode each having a catalyst; and a fuel supply line for supplying a fuel to the anodes of the cells, and an oxidant supply line for supplying an oxidant to the cathodes, the method comprising the steps of: (a) supplying the fuel and the oxidant to the anodes and the cathodes of the cells, respectively, depending on a load to generate power at a constant voltage under constant voltage control; (b) temporarily suspending the supply of the oxidant with the fuel being supplied; and (c) lowering the constant voltage to a predetermined voltage simultaneously with or immediately before the suspension of the supply of the oxidant, wherein in the step (c), the predetermined voltage is a sufficiently low voltage to reduce and reactivate the catalyst of the cathode in all the cells.