Patent ID: 8241809

Claim:
A fuel cell system comprising: a supply conduit which supplies fuel gas from a fuel gas source to a fuel cell; a circulation conduit which returns discharged fuel gas discharged from the fuel cell to the supply conduit, and circulates the discharged fuel gas to the fuel cell; a release unit which is provided in the circulation conduit, and releases the discharged fuel gas to the outside of the fuel cell system; a temperature detection unit which detects the temperature of the fuel gas which flows in the supply conduit; and a determining unit which determines whether or not freezing conditions are present in the supply conduit based on a detection temperature detected by the temperature detection unit while the fuel cell is in operation; and a flow volume control unit which releases at least a portion of the discharged fuel gas from the release unit to the outside of the fuel cell system, and controls the flow volume of the discharged fuel gas to be returned to the supply conduit, when the determining unit determines that freezing conditions are present, wherein, when the determining unit determines that freezing conditions are present, and when the detection temperature is less than or equal to a predetermined value, a volume of discharged fuel gas is returned to the supply conduit, wherein the flow volume control unit is programmed to control the flow volume of the discharged fuel gas to be returned to the supply conduit to be lower than when the detection temperature is greater than the predetermined value.