POWER SUPPLY SYSTEM AND CONTROL METHOD THEREFOR

An electric power supply system comprises a battery that generates heat by discharging an electric power, and a fuel cell system that generates the electric power by fuel cells . The electric power supply system supplies power to an electric load. The electric power supply system determines whether or not a temperature of the battery is equal to or less than a predetermined temperature, and when the temperature of the battery is equal to or less than the predetermined temperature, the electric power supply system discharges the battery to the fuel cell system