FUEL CELL SYSTEM, VEHICLE INCLUDING FUEL CELL SYSTEM, AND CONTROL METHOD OF FUEL CELL SYSTEM

A fuel cell system includes: a fuel cell outputting generated power to an external load; a secondary battery outputting charged power to the external load; and a controller performing a first control that controls output power of the fuel cell and output power of the secondary battery such that the output power of the secondary battery has a ratio predetermined in accordance with an output demand from the external load, in the power supplied to the external load, the controller switches the first control to a second control when the output demand satisfies a predetermined condition with which the output power of the secondary battery is predicted to reach a limit value with the first control, the second control sets a target value of the output power of the fuel cell such that the output power of the secondary battery is smaller than that in the first control.