According to a control method for a hybrid vehicle that is caused to run by a drive motor as a load being supplied with electric power of a battery and electric power generated by an electric generator, a total distance to empty is calculated on the basis of a shortage of a generating power output of the electric generator with respect to a required running power output and an amount of charge remaining in the battery. Specifically, a length of time for which the shortage of the generating power output of the electric generator with respect to the required running power output is covered by the amount of charge remaining in the battery is calculated, and a distance that the hybrid vehicle can run for this length of time is set as a total distance to empty.

A fuel cell system includes an auxiliary machine to be connected to a fuel cell, warm-up power control means for controlling generated power of the fuel cell by adjusting power supplied to the auxiliary machine during the warm-up of the fuel cell, and IV characteristic estimation means for temporarily reducing the power supplied to the auxiliary machine and estimating an IV characteristic of the fuel cell on the basis of at least two pairs of current values and voltage values at that time during the warm-up of the fuel cell.

A fuel cell has an electrolyte membrane of 5 to 10 μm in thickness. A control device for this fuel cell comprises: a controller configured to control an amount of power generation by the fuel cell according to a required amount of electric power; and a power generation reducer configured to reduce the amount of power generation by the fuel cell at a humidity of an electrolyte membrane of 95 to 98% RH to be lower than the amount of power generation at the humidity of the electrolyte membrane of lower than 95% RH.

A fuel cell system comprises: a fuel cell stack; a turbo compressor configured to supply a cathode gas to the fuel cell stack through a cathode gas supply line; a pressure regulation valve configured to regulate a pressure of the cathode gas; and a controller, wherein the controller is configured to calculate a target rotation speed of the turbo compressor and a target opening position of the pressure regulation valve, based on a target flow rate of the cathode gas and a target pressure of the cathode gas that are determined according to a required power output of the fuel cell stack and to control the turbo compressor and the pressure regulation valve using the calculated target rotation speed and the calculated target opening position, and the controller is configured, upon increase of the required power output, to: (a) determine an acceptable overshoot level of a flow rate of the cathode gas that is to be supplied to the fuel cell stack, the acceptable overshoot level being selected from a plurality of levels based on at least an increased amount of the required power output; and (b) set a time change in opening position of the pressure regulation valve such that an overshoot amount in a change of the flow rate of the cathode gas becomes smaller as the acceptable overshoot level gets lower, and perform control of the pressure regulation valve. This configuration suppresses an excessive overshoot in the flow rate of the cathode gas.

The disclosure relates to a fuel cell system comprising a fuel cell stack for providing an electrical power P.sub.stack depending on a power demand, at least one auxiliary unit for operating the fuel cell stack with an electrical power consumption P.sub.aux, at least one consumer with an electrical power request P.sub.use, and a control unit for regulating the power demand as well as a method for controlling such a fuel cell system. It is provided that the control unit is configured to selectively operate the fuel cell system in a first operating mode or in a second operating mode, whereby the fuel cell stack is turned off depending on the operating mode upon the falling below of an optimal efficiency degree operating point P(η.sub.max) of the fuel cell system or a minimum operating point P.sub.min of the fuel cell stack. In particular, at least one auxiliary unit is also turned off in the first operating mode, when the optimal efficiency degree operating point decreases.

A power supply system includes a fuel cell, a power storage, and a processor. The fuel cell and the power storage supply electric power to a load. The processor is configured to control the fuel cell and the power storage. The processor is configured to acquire a required system power that is required in the power supply system. The processor is configured to determine a power storage shared power such that power efficiency of the electric power supplied from the power storage to the load is equal to or higher than a first value. The processor is configured to determine a fuel cell shared power such that the electric power supplied from the fuel cell is a difference between the power storage shared power and the required system power.

When a temperature measured by a temperature measurer is below a specified temperature, a controller of a fuel cell system activates a fuel-gas-concentration increasing mechanism by using electric power of a secondary battery, and executes a fuel-gas-concentration increasing process for increasing the fuel gas concentration toward a first target concentration. When the fuel gas concentration reaches equal to or more than a second target concentration lower than the first target concentration, the controller starts power generation by a fuel cell to activate the fuel-gas-concentration increasing mechanism by using electric power from the fuel cell, and executes the fuel-gas-concentration increasing process until the fuel gas concentration reaches the first target concentration or more.

An illustrative example fuel cell power plant includes a cell stack assembly having a plurality of fuel cells configured to generate electricity based on an electrochemical reaction. The power plant includes a capacitor, a plurality of inverters, and at least one controller that is configured to control the plurality of inverters in a first mode and a second mode. The first mode includes the cell stack assembly associated with at least one of the inverters. A cell stack assembly and the associated inverter provide real power to a load external to the fuel cell power plant in the first mode. The second mode includes at least a second one of the inverters associated with the capacitor. The capacitor and the second one of the inverters selectively provide reactive power to or receive reactive power from a grid external to the fuel cell power plant in the second mode.

A first outer peripheral seal in a first metal separator of a fuel cell stack includes a first peripheral metal bead. A first bypass stopper is provided in a space between a first end ridge and a first outer peripheral seal. The first bypass stopper prevents bypassing of an oxygen-containing gas by blocking part of the space. A gap is provided between the first bypass stopper and the first metal bead of a first outer peripheral seal. The gap separates the first bypass stopper from the first metal bead.

A fuel cell system with a plurality of fuel cell modules connected to form a fuel cell group having first and second electrical supply terminals that terminate to an electrical load; a measuring device connected to the fuel cell modules that measures a load current of the respective fuel cell modules; and a controller that detects a respective operating state of the fuel cell modules. The controller is connected to and controls operation of the fuel cell modules, and detects whether the operating state is in a respective partial load range of the respective fuel cell module. The controller provides a load current demanded by the load in a first partial-load operating mode of the load by operating all fuel cell modules of the fuel cell group such that all of the fuel cell modules are within the respective partial load range of the respective fuel cell module.