Abstract: A system and method for draining remaining water in a gas passage of a fuel cell, which has a simple structure and the remaining can be efficiently and reliably drained outside. Water which remains in a gas passage of the fuel cell is first drained by increasing the flow rate of the reaction gas while the operation of the fuel cell is stopped. The remaining water which has not been drained is then drained by increasing the pressure of the reaction gas and then decreasing the increased pressure. The increase and decrease operation of the pressure of the reaction gas is started after the increase of the flow rate of the reaction gas is started. Typically, the increase of the pressure of the reaction gas is started when a predetermined time has elapsed after the increase of the flow rate of the reaction gas is started.

Abstract: A stop method for a fuel cell system that includes a fuel cell unit in which hydrogen is supplied to an anode, and air is supplied to a cathode so as to generate electrical power via an electrochemical reaction. The stop method includes the steps of stopping supply of hydrogen to the anode, and supplying air to the anode so as to discharge water remaining at the anode.

Abstract: A start-up method for a fuel cell system that includes a fuel cell that carries out power generation by the electrochemical reaction between a fuel gas and the oxygen gas in the air; a fuel gas discharge path and a fuel gas supply path that are connected to the fuel cell; a fuel gas circulation path in which the fuel gas discharge path merges with the fuel gas supply path; and a purge valve provided on the fuel gas circulation path in order to discharge the circulating fuel gas from the fuel gas circulation path. The method includes the steps of opening the purge valve at the same time that the fuel gas is supplied to the fuel cell and replacing the nitrogen gas that originates in the air and is present in the fuel gas circulation path by fuel gas; and closing the purge valve after the nitrogen gas in the fuel gas circulation path has been replaced by the fuel gas.

Abstract: A fuel cell system includes a fuel cell in which a first reactant gas and a second reactant gas are supplied to generate electricity. An evaporator evaporates a raw fuel, which combustor exhaust gas discharged from the fuel cell and uses the exhaust gas to evaporate and volatile a raw material for the first reactant gas. A reformer reforms the evaporated and volatilized raw fuel vapor of the raw material by a reforming catalyst to produce the first reactant gas. An air-introducing device introduces the air that is used to be reformed into the evaporator or the reformed in a manner wherein the flow rate of the air is controlled depending upon the output from the fuel cell and upon the temperature of the raw fuel vapor.

Abstract: A bypass plate and an intermediate plate are interposed between a stack body and a negative electrode terminal of a fuel cell stack. An oxygen-containing gas passage extends through the bypass plate and the stack body. The intermediate plate has a small opening. The opening has a cross sectional area smaller than a cross sectional area of the oxygen-containing gas supply passage. The opening is formed by an extension extending into the oxygen-containing gas supply passage. The extension removes water in the oxygen-containing gas, and discharges the water into a bypass flow passage.

Abstract: A system and method for draining remaining water in a gas passage of a fuel cell, which has a simple structure and the remaining can be efficiently and reliably drained outside. Water which remains in a gas passage of the fuel cell is first drained by increasing the flow rate of the reaction gas while the operation of the fuel cell is stopped. The remaining water which has not been drained is then drained by increasing the pressure of the reaction gas and then decreasing the increased pressure. The increase and decrease operation of the pressure of the reaction gas is started after the increase of the flow rate of the reaction gas is started. Typically, the increase of the pressure of the reaction gas is started when a predetermined time has elapsed after the increase of the flow rate of the reaction gas is started.

Abstract: A fuel cell system comprises a fuel cell in which first reactant gas and second reactant gas are supplied to generate electricity, an evaporator for evaporating a raw fuel, which combusts exhaust gas discharged from said fuel cell and makes use of said exhaust gas to evaporate and volatize a raw material for said first reactant gas, a reformer which reforms the evaporated and volatilized raw fuel vapor by means of a reforming catalyst to produce the first reactant gas, and an air-introducing device, which introduces air used to be reformed into the evaporator or the reformed in a manner that the flow rate of the air is controlled depending upon the output from the fuel cell and upon the temperature of the raw fuel vapor.