Patent ID: 8927168
Filing Date: 2015-01-06
Classification: H01M,Y02E

Abstract:
1. A fuel cell system comprising: a fuel cell which generates power by an electrochemical reaction between air supplied to an oxidant gas flow path and hydrogen supplied to a fuel gas flow path; an air flow rate obtaining unit which obtains a flow rate of the air supplied to the oxidant gas flow path; a voltage sensor which obtains an actual operation voltage of the fuel cell; a current sensor which obtains an operation current of the fuel cell; and a controller, including a computer which executes signal processing and a memory which stores a control program, which adjusts an amount of the air supplied to the fuel cell, wherein the controller, for use during a low-efficiency operation in which the stoichiometric ratio of the air is reduced from a stoichiometric ratio of the air during a normal operation and heat discharged from the fuel cell is increased from that during the normal operation, is programmed to: calculate the actual stoichiometric ratio of the air based on the flow rate of the air obtained by the air flow rate obtaining unit with an actual stoichiometric ratio calculating unit; calculate a theoretical amount of pumping hydrogen based on the actual stoichiometric ratio of the air and the operation current of the fuel cell, and corrects the theoretical amount of pumping hydrogen based on a correction coefficient determined in accordance with a voltage difference between a voltage of the fuel cell in a normal state with no water blockage corresponding to the actual stoichiometric ratio of the air and the actual operation voltage of the fuel cell to obtain a corrected amount of pumping hydrogen with a pumping hydrogen amount correcting unit; calculate a necessary amount of dilution air based on the corrected amount of pumping hydrogen obtained by the pumping hydrogen amount correcting unit with a necessary air flow calculating unit; and increase the air flow rate to the necessary flow rate of dilution air calculated by the necessary air amount calculating unit with an air flow increasing unit.