A fuel cell system includes a fuel cell stack configured to generate power according to a load, a fuel tank configured to store fuel gas, a pressure regulating valve configured to regulate a pressure of the fuel gas supplied from the fuel tank to the fuel cell stack, a purge valve configured to purge the fuel gas discharged from the fuel cell stack and a controller for controlling the system. The controller includes a pulsating unit configured to cause a fuel gas pressure of the fuel cell stack to pulsate, and a pressure increasing rate setting unit configured to set a pressure increasing rate of the pulsation of the fuel gas pressure according to an operating state.

A fuel cell system includes an auxiliary machine driven by power of the fuel cell, a heater electrically connected to the fuel cell and configured to heat cooling water supplied to the fuel cell, and a warm-up control unit configured to control power supply to the auxiliary machine and the heater during start-up of the fuel cell below freezing point. The warm-up control unit is configured to compute a produced water amount until the temperature of the fuel cell increases to a freezing point temperature on the basis of a degree of wetness and a temperature of the fuel cell and a generated power of the fuel cell during warm-up, and increase a power ratio of power to the heater in regards to the auxiliary machine during the warm-up when the computed produced water amount is determined to be larger than a threshold value.

A system and method for controlling operation of a fuel cell are provided. The method includes estimating an effective catalyst amount within a fuel cell stack and monitoring a change in the estimated effective catalyst amount according to time. An irreversible degradation state of the fuel cell stack is determined based on the monitored change in the estimated effective catalyst amount.

A fuel cell system calculates a target value of a flow rate of cathode gas to be supplied to a fuel cell stack according to a request of the fuel cell stack, controls a flow rate of the cathode gas to be supplied by the compressor according to an operating state of the fuel cell system, controls a bypass valve based on a target fuel cell supply flow rate so that the flow rate of the cathode gas to be supplied from the compressor to the fuel cell stack reaches the target fuel cell supply flow rate, and limits the flow rate of the cathode gas to be supplied by the compressor when the bypass valve has a predetermined opening and the flow rate of the cathode gas to be supplied to the fuel cell stack is not smaller than the target fuel cell supply flow rate.

The present invention relates to a separator and a fuel cell stack comprising the same, and according to one aspect of the present invention, there is provided a separator comprising a plurality of channels including a bottom forming a flow space for a reaction gas to flow and a pair of sidewalls connected to the bottom, and a plurality of ribs provided so as to connect the sidewalls of two adjacent channels, wherein the sidewall of the channel is provided with a water storage part which is recessed inward and has a first inclined surface and a second inclined surface connected by a first angle.

A fuel cell system includes a fuel cell, an accumulator configured to store a fuel gas, a gas remaining quantity acquisition unit configured to obtain a remaining quantity of the fuel gas stored in the accumulator, and a power generation control unit. When the remaining quantity of the fuel gas stored in the accumulator is decreased to a threshold value, the power generation control unit performs switching from humid power generation control to dry power generation control.

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.

A system for measuring a moisture content of an ion-exchange membrane in a fuel-cell stack is provided. The fuel-cell stack includes N electrochemical cells separated by bipolar plates, with N being a natural integer. The system includes a current generator, a voltage measurement device, and an impedance measurement device. The current generator enables a current to be applied to the fuel-cell stack. The voltage measurement device measures voltages of the cells of the fuel-cell stack. The impedance measurement device determines an impedance of an ion-exchange membrane according to a voltage ripple measured by the voltage measurement device across terminals of a corresponding one of the cells of the fuel-cell stack when the current is applied by the current generator. The impedance measurement device is installed in the voltage measurement device.

A fuel cell control method and are provided. The method includes collecting state data of a fuel cell stack and then estimating an effective catalytic amount of the fuel cell stack based on the collected state data. A fuel cell system is operated based on the estimated effective catalytic amount to thus optimize the efficiency of the system.

A fuel cell system includes: a fuel cell stack; a fuel gas supply/exhaust unit; an oxidant gas supply/exhaust unit; and a control unit. The control unit determines whether there is a phenomenon in the fuel cell stack resulting from local power generation concentration within a plane of a membrane electrode assembly due to a water distribution. When it is determined that there is the phenomenon, the control unit controls at least one of the fuel gas supply/exhaust unit and the oxidant gas supply/exhaust unit.