Patent ID: 8173313
Filing Date: 2012-05-08
Classification: H01M,Y02E

Abstract:
1. A method of stopping a fuel cell system comprising a solid polymer fuel cell having a solid polymer membrane for separating anode gas and cathode gas, a resistor connected to cables, one of which is connected to a current collector of a cathode or an anode, and the other is connected to an inverter, a switch for switching selectively electrical connection between the fuel cell and the inverter or between the fuel cell and the resistor, an anode gas supply valve and an anode gas discharge valve, a cathode gas supply valve, a cathode gas discharge valve, and a computer for controlling the supply valves and discharge valves, which comprises switching on one of the resistor or the inverter and the fuel cell to cause electric current generated in the fuel cell to be consumed by the resistor or the inverter until a molar ratio of hydrogen to oxygen in the fuel cell system becomes 2/1 or less, closing the supply valve for the anode gas for a time integral value until Tmin, determined by 2F·(Ma−2Mc)=Q(Tmin) and Q(Tmin)=∫V/Rd dt, Ma being the molar number of hydrogen, Mc being the molar number of oxygen, F being Faraday's number, V being a voltage of the fuel cell system, Rd being a resistance value of the resistor, Tmin being the resistor connection time after closing the supply valve for the anode gas, and Q being quantity of electricity for hydrogen oxidation, for current flowing when the resistor and an output terminal of the fuel cell system are connected, and then, closing the cathode gas supply valve to the fuel cell when a molar ratio of the hydrogen contained in the anode gas to oxygen contained in the cathode gas becomes a molar ratio of hydrogen to oxygen to be less than 2/1 to thereby make an output of the fuel cell zero.