Patent ID: 7294422

Claim:
A cooling method for a fuel cell, in which heat produced during power generation in said fuel cell is dissipated by circulating a cooling fluid and by using a heat exchanger and a thermostat provided for switching flow passages of said cooling fluid depending on the temperature thereof, the method comprising the steps of: providing an ion exchanger, for removing ions contained in said cooling fluid, in a circulation system for said cooling fluid; removing ions contained in said cooling fluid by circulating said cooling fluid through said fuel cell and said ion exchanger while allowing a portion of said cooling fluid to substantially stand in said heat exchanger when the temperature of said cooling fluid is below a thermostat operating temperature at which the thermostat valve of said thermostat is operated; removing ions contained in said cooling fluid in said heat exchanger by circulating a portion of said cooling fluid through said heat exchanger and said ion exchanger, when the temperature of said cooling fluid is approaching said thermostat operating temperature; and cooling said fuel cell by circulating said cooling fluid through said fuel cell and said heat exchanger after the temperature of said cooling fluid reaches said thermostat operating temperature.