In a method of activating a fuel cell, after a voltage application step is performed, a humidifying step is performed. In the voltage application step, a hydrogen gas is supplied to an anode, and an inert gas is supplied to a cathode. In the meanwhile, cyclic voltage which is increased and decreased within a predetermined range is applied to the fuel cell. In the humidifying step, in a state where application of the voltage is stopped, a humidified gas containing water vapor is supplied to at least one of the anode and the cathode.

There is provided a fuel cell system. This fuel cell system comprises a fuel cell configured to generate electric power using reactive gases; a voltage sensor configured to measure a voltage output from the fuel cell; a converter configured to boost an input voltage that is input from the fuel cell; and a controller configured to control the converter. In the case where the voltage output from the fuel cell to the converter is to be boosted after a changeover of an operating state of the fuel cell system from an intermittent operation to an ordinary operation, when a duty ratio D1 calculated by Mathematical Formula I is greater than a duty ratio D2 calculated by Mathematical Formula II, the controller causes the converter to boost the voltage output from the fuel cell at the duty ratio D2. $\begin{array}{cc}\left[\mathrm{Math}.1\right]& \\ D1=1-\frac{\mathrm{Vltrg}}{\mathrm{VH}}& \left(I\right)\end{array}$
where VH (V) denotes a value of output voltage that is output from the converter, and Vltrg (V) denotes an estimated value of voltage that is output from the fuel cell, $\begin{array}{cc}\left[\mathrm{Math}.2\right]& \end{array}$

A control device is configured to control a first boost converter and a second boost converter. The control device is configured such that, when a prescribed state where an output of the second boost converter cannot be made at a ratio of an output voltage to an input voltage in the second boost converter to be equal to or more than a predetermined value is detected, the control device calculates a target output voltage of a fuel cell by using an voltage on an input side or an output side of the second boost converter measured by a measuring portion and a first value which is equal to or larger than a minimum boost ratio of the first boost converter, and controls the fuel cell so that an output voltage of the fuel cell is equal to or lower than the target output voltage.

The present invention relates to a method and system for controlling a stop mode of a fuel cell. In particular, the present invention provides a method and system for controlling a stop mode of a fuel cell which are characterized by calculating the degree of deterioration of a fuel cell, determining a stopping voltage in accordance with the calculated degree of deterioration, and controlling an output voltage of the fuel cell to be the determined stopping voltage.

A method of operating a fuel cell assembly comprising a plurality of fuel cells connected together for collectively providing power to a load, each fuel cell including an anode and a cathode, the method comprising selectively providing an electrical connection between the anode and the cathode of at least one of the fuel cells of the assembly for lowering the voltage across the fuel cell independent of the load.

A method of improving the electrical performance of an operating fuel cell catalyst-containing cathode in a fuel cell connected to an electrical load by: reducing the flow of air to the cathode; disconnecting the load from the fuel cell; connecting a potentiostat to the fuel cell; cycling an applied voltage, current, or power to the fuel cell one or more times; disconnecting the potentiostat from the fuel cell; reconnecting the load to the fuel cell; and resuming the flow of air to the cathode.

A method for observing a state of an electrochemical system including a fuel cell including the following steps: measuring parameters that are representative of the fuel cell in operation; forming a control vector; forming a measurement vector; calculating a temporal variation, referred to as a non-corrected temporal variation; calculating a corrective term in sliding mode; calculating an estimate of the state of the electrochemical system; reiterating above steps while incrementing the measurement time.

The present disclosure relate to a method for operating a redox flow battery, which includes the steps of discharging the redox flow battery having an anode electrolyte and a cathode electrolyte when a volume difference between the anode electrolyte and the cathode electrolyte is within 20% of a total volume of the anode electrolyte and the cathode electrolyte, while maintaining an open circuit voltage of lower than 1.3 V/cell, and moving the anode electrolyte and/or the cathode electrolyte so that the volume difference is 2% or less between the anode electrolyte and the cathode electrolyte in the redox flow battery after the discharging.

The object of the present invention is to balance: the suppression of deterioration of a fuel cell and degradation of its durability and the optimization of the output control of the fuel cell. The present invention provides an output control apparatus for a fuel cell, being capable of switching a control mode between a power control mode in which an output power of a fuel cell connected to a load is controlled so as to be at a target power and a voltage control mode in which an output voltage of the fuel cell is controlled so as to be at a target voltage, wherein a control in the voltage control mode is performed when the output voltage of the fuel cell decreases below a predetermined low voltage threshold value.

An industrial vehicle having a fuel cell system includes a vehicle key switch which has at least an ON position and an OFF position and is switchable between the ON position and the OFF position and a controller configured to control the fuel cell system in conjunction with manipulation of the key switch. When the controller detects that the key switch is turned from the OFF position to the ON position, the controller causes the fuel cell system to start electric power generation. When the controller detects that the key switch is turned from the ON position to the OFF position, the controller causes the fuel cell system to start a voltage maintenance control. When the controller detects that the key switch at the ON position is manipulated in a specified manner, the controller causes the fuel cell system to stop the electric power generation.