Patent ID: 7846592

Claim:
A fuel cell system, comprising: a fuel cell which generates power with a supply of liquid fuel; a fuel supply unit which supplies the liquid fuel to said fuel cell and recovers generated water from said fuel cell; a fuel state detector, provided in said fuel supply unit, which detects a water level of the liquid fuel including the generated water; and a controller which changes an electric power value outputted from said fuel cell, based on the water level detected by said fuel state detector, wherein in accordance with the detected water level, the controller controls the fuel cell so that (1) output current of the fuel cell becomes greater than output current obtained when an amount of evaporation of the generated water in the fuel supply unit is equal to an amount of water generated in the fuel cell to increase water to be generated in the fuel cell or (2) the output current of the fuel cell becomes less than the output current obtained when the amount of evaporation of the generated water in the fuel supply unit is equal to the amount of water generated in the fuel cell to decrease the water to be generated in the fuel cell.