FUEL CELL SYSTEM

A fuel cell system mounted on a vehicle includes: a fuel cell stack; a refrigerant circulation passage connected to the fuel cell stack; a refrigerant circulation pump arranged in the refrigerant circulation passage and configured to circulate a refrigerant; and a controller configured to control a power generation amount of the fuel cell stack according to a request driving force of the vehicle and control the refrigerant circulation pump. The controller is configured to set a rotational speed of the refrigerant circulation pump within a range equal to or lower than a rotational speed upper limit based on a temperature of the fuel cell stack, and the controller sets the rotational speed upper limit lower at a time a vehicle speed is equal to or lower than a stop determination value as compared with a time the vehicle speed is higher than the stop determination value.