| 摘要 |
A fuel cell system employing a dead end system and capable of producing power with high efficiency. A fuel cell (2) is operated under a state where the channel (10) of fuel off gas is closed. From time (t<SUB>0</SUB>) to time (t<SUB>1</SUB>), pressure of hydrogen supplied to the anode is set at P<SUB>1</SUB>. Preferably, P<SUB>1</SUB> is such a pressure that a minimum quantity of hydrogen required for power generation of the fuel cell (2) can be supplied to the anode. With such a pressure, the quantity of hydrogen permeating an electrolytic membrane and moving to the cathode side can be minimized. In order to suppress voltage drop of the fuel cell (2), the pressure of hydrogen is altered from P<SUB>1</SUB> to P<SUB>2</SUB> (where, P<SUB>2</SUB>>P<SUB>1</SUB>) upon elapsing a predetermined time (t<SUB>1</SUB>) after starting operation. When the pressure of hydrogen is elevated, the quantity of hydrogen permeating the electrolytic membrane (15) increases and thereby utilization efficiency of hydrogen deteriorates. The pressure (P2) of hydrogen supplied to the anode and the timing (t<SUB>1</SUB>) for elevating the pressure are preferably determined while voltage drop of the fuel cell (2) and deterioration in utilization efficiency of hydrogen are taken account of. |
