FUEL CELL SYSTEM

PROBLEM TO BE SOLVED: To provide a control system of a fuel cell that can identify the factor of cell voltage drop. SOLUTION: When the voltage of the fuel cell 1 is judged to be dropped, the following assumption is made at the factor assumption part 17. When the voltage of a part of the cluster drops out of the voltage of a cluster including at least one cell, the factor of voltage drop is assumed as a flooding. When the pressure response of the fuel gas in the fuel circulation piping 6 drops further than a permissible range, the factor of the voltage drop is assumed as an increase of impurities in the fuel circulation piping 6. Furthermore, when the factor of voltage drop is assumed as no-flooding nor increase of impurities, the factor of voltage drop is estimated as an insufficient humidifying of the electrolyte membrane. COPYRIGHT: (C)2004,JPO