FUEL CELL SYSTEM AND METHOD OF CONTROLLING FUEL CELL SYSTEM

In a fuel cell system and a method of controlling the fuel cell system, correlation temperature correlated to temperature of a fuel cell stack is obtained. Further, temperature of a heating unit provided at the bottom of a water storage area of a gas liquid separator is estimated. The presence/absence of water in the gas liquid separator is determined based on the correlation temperature of the fuel cell stack and the temperature of the heating unit.