Provided are a recovery control system of a fuel cell and a method thereof. The recovery control system includes the fuel cell, a hydrogen supplier configured to supply hydrogen to the fuel cell, an air supplier configured to supply air to the fuel cell, an abnormality sensing unit configured to calculate a difference between a reference cell voltage predetermined depending on an output current of the fuel cell and a measured cell voltage of unit cells and to sense abnormality of air supply to a fuel cell stack based on the calculated difference between the reference cell voltage and the measured cell voltage or change in the difference, and a recovery controller configured to control the air supplier so as to increase a flow rate of air supplied to the fuel cell stack based on the change in the difference, when the abnormality sensing unit senses abnormality of air supply.

A method for starting a fuel cell in a fuel cell system, at temperatures below the freezing point of water, includes, in a first step, that the hydrogen concentration in the anode is increased; after which, in a second step, an anode pressure is increased for a fixed period of time, and while air is supplied to the cathode, the maximum possible current is drawn from the fuel cell, and after which, in a third step, the fuel cell is switched in a load-free manner and the anode pressure is reduced. After the third step, the second step and the third step are repeated successively until a sufficient performance of the fuel cell for its normal operation is reached.

An electrical system includes a stack (3) of electrochemical cells (5), a power converter (9) electrically connected to the stack (3), a voltage comparator (7) for comparing the voltage at the terminals of at least one group of at least one electrochemical cell (5) of the stack (3) to a threshold voltage, and a control module (11) for controlling the converter (9). The control module (11) includes a generator (74) for generating a control instruction for controlling the converter (9) and a transmission member (76) for transmitting the control instruction to the converter (9). The voltage comparator (7) is suitable for transmitting a signal to the transmission member (76). The signal consists of a first instruction from an instruction for transmitting and an instruction for blocking the control instruction when the compared voltage is higher than the threshold voltage, and a second instruction from the instructions for transmitting and blocking the control instruction when the compared voltage is lower than or equal to the threshold voltage.

A system and method for recovering an output of a fuel cell is provided. The system and method for recovering an output of a fuel cell includes: an output recovering device connected to a fuel cell stack through at least one coolant heater line; and a vehicle controller configured to communicate with the output recovering device and control supply of a coolant, air, and hydrogen to the fuel cell stack. The output recovering device also includes a current supplier configured to supply a current to the fuel cell stack and a controller configured to communicate with the vehicle controller and control the current supplied from the current supplier.

The low efficiency power generation part of a control device is provided with an operating point setting part setting a target current and a target voltage defining an operating point of the fuel cell at the time of low efficiency power generation and a generated electric power control part making the generated electric power of the fuel cell increase and decrease at the time of low efficiency power generation by controlling the current of the fuel cell to the target current while making the flow rate of feed of oxidizing agent gas supplied to the fuel cell fluctuate so that the voltage of the fuel cell increases and decreases above and below the target voltage within a range where the charged and discharged electric powers of the rechargeable battery do not become larger than the allowable charged and discharged electric powers.

A system and method for controlling power for a fuel cell are disclosed. The system includes: a fuel cell; a load device electrically connected to the fuel cell; a stack controller configured to set a stack limit current on the basis of a current output current of the fuel cell, the stack limit current configured to limit an output current of the fuel cell on the basis of an output voltage of the fuel cell; and a load controller configured to set a consumption limit current on the basis of the set stack limit current, the consumption limit current configured to limit a consumption current of the load device, the load controller being configured to control the consumption current of the load device to a value equal to or lower than the set consumption limit current.

A fuel cell system includes a fuel cell stack configured to supply power to an electric motor for driving a vehicle as well as generating power by an electrochemical reaction between a fuel gas and an oxidant gas, a discharge circuit and the discharge control circuit. The discharge circuit may form a plurality of discharge paths through which power generated in the fuel cell stack is discharged switching elements switching the connection relationships between resistance elements. The discharge control circuit form a second discharge path whose resistance value is smaller than the resistance value of the first discharge path and to switch the discharge through a first discharge path to discharge through the second discharge path when the detected voltage that is detected by the voltage detection unit is lower than a predetermined threshold voltage during the discharge through the first discharge path.

A system and method for controlling a fuel cell system. An anode tail gas oxidizer (ATO) receives air and fuel exhaust streams from one or more fuel cell stacks of the fuel cell system. The one or more fuel cell stacks provide current to one or more loads. An ATO temperature signal is used to control at least one of a fuel inlet flow to the one or more fuel cell stacks or the current provided to the one or more loads.

First, a reaction gas is supplied to a fuel cell stack including a laminate of solid polymer electrolyte fuel cells and power generation is performed so that a temperature of the fuel cell stack reaches 65° C. or higher (heating power generation step). Next, the reaction gas is supplied to the fuel cell stack and the power generation is performed under a condition in which relative humidity is 100% or more (cleaning power generation step). Cooling water of room temperature may be supplied to the fuel cell stack from the outside before the cleaning power generation step is performed after the heating power generation step is completed, or after the cleaning power generation step is completed (quenching step).

This fuel cell stack activation method is a method for activating a fuel cell stack provided with a solid polymer-containing electrolyte membrane, an anode electrode, and a cathode electrode, the method comprising: a first current application step for applying a current by electrically connecting the two electrodes via an external electrical load in a state in which a potential difference is generated between the two electrodes by supplying air as a cathode-side gas to the cathode electrode while supplying hydrogen gas as an anode-side gas to the anode electrode; and a second current application step for applying a current by electrically connecting the two electrodes via an external electrical load in a state in which a potential difference is generated between the two electrodes by supplying nitrogen gas as a cathode-side gas to die cathode electrode while supplying hydrogen gas as an anode-side gas to the anode electrode.