FUEL CELL SYSTEM AND CONTROL METHOD FOR FUEL CELL SYSTEM

The low efficiency power generation part of a control device is provided with an operating point setting part setting a target current and a target voltage defining an operating point of the fuel cell at the time of low efficiency power generation and a generated electric power control part making the generated electric power of the fuel cell increase and decrease at the time of low efficiency power generation by controlling the current of the fuel cell to the target current while making the flow rate of feed of oxidizing agent gas supplied to the fuel cell fluctuate so that the voltage of the fuel cell increases and decreases above and below the target voltage within a range where the charged and discharged electric powers of the rechargeable battery do not become larger than the allowable charged and discharged electric powers.