FUEL CELL SYSTEM AND METHOD OF CONTROLLING OPERATION OF FUEL CELL

A fuel cell system includes a fuel cell (100) including an electrolyte membrane (90), a sensor (450) configured to measure a temperature of the fuel cell (100), and a controller (610). The controller (610) is configured to cause the fuel cell (100) to perform a wet operation to increase a water balance at a cathode of the fuel cell (100) to a value higher than a water balance at the cathode during a normal operation of the fuel cell (100), when the temperature of the fuel cell (100) measured by the sensor (450) is maintained at a first threshold temperature or higher for a prescribed period of time or longer and then the temperature of the fuel cell (100) decreases to below a second threshold temperature that is equal to or lower than the first threshold temperature.