A fuel cell system performs a first control of stopping power generation of a fuel cell stack by closing a supply-side stop valve during power generation of the fuel cell stack, and a second control of driving an air pump by using surplus power generated in a moving body to thereby discard the surplus power. If a closed state of the supply-side stop valve is detected when the first control and the second control start to be executed, the air pump is driven in a predetermined state.

A power supply apparatus configured to control output power from a fuel cell module that generates power using combustion gas includes a controller that, during operation in parallel with other power supply apparatuses that supply output power from other fuel cell modules to a load, controls the output power from one fuel cell module among the fuel cell module and the other fuel cell modules until the one fuel cell module reaches rated power output, while suppressing the output power from each fuel cell module, other than the one fuel cell module, that has not reached the rated power output.

A method for controlling startup of a fuel cell vehicle is provided. The method includes starting to adjust supply of hydrogen and air to a fuel cell and setting a control voltage of a side of a main bus end of a converter disposed between the main bus end and a high-voltage battery to a predetermined lowest control voltage. An output voltage of the side of the main bus end of the fuel cell and the control voltage of the side of the main bus end of the converter are then compared to adjust an amount of air supply to the fuel cell based on the comparison.

A controller (control portion) of a fuel cell system is provided with a flow path switching control device that switches a thermostat valve (flow path switching valve) so that, after a fuel cell has stopped generating electric power, coolant is supplied to a radiator circulation path until the coolant temperature becomes a second temperature threshold value that is lower than a first temperature threshold value.

Systems and methods for operating a redox flow battery system may include switching the redox flow battery system to an idle mode, wherein the idle mode includes operation of the redox flow battery system outside of a charging mode and outside of a discharge mode; in response to switching to the idle mode, repeatedly cycling operation of an electrolyte pump between an idling threshold flow rate less than a charging threshold flow rate and a deactivation threshold flow rate; and in response to switching to the charging mode, maintaining operation of the electrolyte pump at the charging threshold flow rate greater than the idling threshold flow rate. In this way, a responsiveness of the redox flow battery system to charging and discharging commands can be maintained while in idle, while reducing parasitic pumping losses due to pumping and heating, and reducing shunt current losses.

Systems and methods for operating a redox flow battery system may include switching the redox flow battery system to an idle mode, wherein the idle mode includes operation of the redox flow battery system outside of a charging mode and outside of a discharge mode; in response to switching to the idle mode, repeatedly cycling operation of an electrolyte pump between an idling threshold flow rate less than a charging threshold flow rate and a deactivation threshold flow rate; and in response to switching to the charging mode, maintaining operation of the electrolyte pump at the charging threshold flow rate greater than the idling threshold flow rate. In this way, a responsiveness of the redox flow battery system to charging and discharging commands can be maintained while in idle, while reducing parasitic pumping losses due to pumping and heating, and reducing shunt current losses.

A method is provided for operating a fluid conveying device of a motor vehicle having at least one aerodynamic bearing. The method reduces the rotational speed of the aerodynamic bearing to a rest speed, wherein the rest speed is below a lifting speed, in which case the bearing builds up an air film for bearing free of mixed friction, and wherein the rest speed is above a lowering speed, in which case the bearing has reduced the air film such that mixed friction occurs. The fluid conveying device is operated at the rest speed.

A method is provided for operating a fluid conveying device of a motor vehicle having at least one aerodynamic bearing. The method reduces the rotational speed of the aerodynamic bearing to a rest speed, wherein the rest speed is below a lifting speed, in which case the bearing builds up an air film for bearing free of mixed friction, and wherein the rest speed is above a lowering speed, in which case the bearing has reduced the air film such that mixed friction occurs. The fluid conveying device is operated at the rest speed.

The invention relates to a method for operating a fuel cell system (10) using a first operating mode, in which, when all of the fuel cell stacks (22, 26) are inactive, one fuel cell stack (22) is pre-heated using a coolant that is pre-heated by means of an electric heater (42) while bypassing all cooler circuits (58) of the active coolant circuits (14) via bypass lines (64) and the one pre-heated fuel cell stack (22) is activated in order to pre-heat an additional fuel cell stack (26) of the fuel cell system. Other operating modes for operating a fuel cell system are disclosed in additional embodiments.

A control unit of an aging apparatus performs a first pattern of supplying a humidified H.sub.2 gas to an anode and supplying a humidified N.sub.2 gas to a cathode, to thereby move protons from the anode to the cathode through an electrolyte membrane. Further, the control unit performs a second pattern of supplying the humidified N.sub.2 gas to the anode and supplying the humidified H.sub.2 gas to the cathode, to thereby move protons from the cathode to the anode through the electrolyte membrane.