Fuel cell hybrid system and method for charging rechargeable battery thereof

A fuel cell hybrid system comprising a fuel cell stack, a rechargeable battery, a control unit and a dc/dc converter connected between the fuel cell stack and the rechargeable battery. The control unit is adapted to charge the rechargeable battery with energy from the fuel cell stack by causing the dc/dc converter to output a voltage that is lower than the maximum charging voltage of the rechargeable battery.