The disclosure relates to a fuel cell stack and corresponding method of operating the fuel cell stack. The method comprises: determining a maximum allowable current that may be drawn from the fuel cell stack; repeatedly determining a magnitude of change to the prevailing maximum allowable current based on a prevailing allowable current ramp rate and an actual measured current of the fuel cell stack; updating the maximum allowable current according to the periodically determined magnitude of change; and controlling operating parameters of the fuel cell stack according to the prevailing maximum allowable current.

A fuel cell system includes: a first fuel cell stack and a second fuel cell stack; a supply passage connected to an inlet of oxidant gas in the first fuel cell stack; an discharge passage connected to an outlet of the oxidant gas in the second fuel cell stack; introduction unit that introduces water in the oxidant gas flowing through the discharge passage into the supply passage; and a controller configured to perform refresh control of the first fuel cell stack by lowering voltage of the first fuel cell stack, and operates, during the refresh control, the introduction unit while keeping the second fuel cell stack in an electric power generation state.

A temperature sensor of a fuel cell system detects, as a start-up time temperature, the temperature of a fuel cell stack or the outside temperature at the time of starting operation. A memory stores a plurality of current limitation patterns. A current limiting unit selects a current limitation pattern based on the detected start-up time temperature, and limits electrical current collected from the fuel cell stack based on the selected current limitation pattern and the temperature during operation of the fuel cell stack detected by the temperature sensor. A threshold value for a period until the temperature of the fuel cell stack reaches a reference temperature is set to be smaller as the start-up time temperature at which the current limitation pattern is selected from the plurality of current limitation patterns becomes lower.

A fuel cell system is disclosed, which includes an anode recirculation loop including a fuel cell stack for generating power, a fuel supply device for providing a fuel to the anode recirculation loop, an air supply device for providing air to a cathode of the fuel cell stack, a voltage monitoring device for monitoring a voltage of the fuel cell stack, and an anode protection controller. The anode protection controller decreases a current drawn from the fuel cell stack by a predetermined amount whenever the voltage of the fuel cell stack drops below a predetermined voltage threshold and decreases a fuel flowrate provided to the anode recirculation loop based on the decreased current, so as to maintain a steam to carbon ratio in the anode recirculation loop above a predetermined steam to carbon ratio limit. A shutdown method for the fuel cell system are also disclosed.

The present invention relates to a fuel cell system and a control method therefor. An aspect of the present invention provides a fuel cell system comprising: a fuel cell stack; a memory unit in which a plurality of current-voltage curves, which are determined according to operation conditions of the fuel cell stack, are stored; a measurement unit for detecting an operation condition of the fuel cell stack; and a control unit for calling a current-voltage curve which satisfies the operation condition of the fuel cell stack, detected by the measurement unit, and predicting the performance of the fuel cell stack according to the called current-voltage curve.

Various embodiments of the present disclosure provide a fuel cell system configured to modulate the flow of oxidant through the fuel cell system to maintain a desired temperature at the fuel cell stack. The fuel cell system is configured to control the flow of oxidant to maintain the desired temperature in the fuel cell stack based on temperature measurements of fluid outside of the fuel cell stack.

A fuel cell system including: a fuel cell; a voltage sensor that measures output voltage of the fuel cell; a converter that boosts the output voltage; and a control unit that controls the converter using a duty ratio including a feedforward term and a feedback term, the feedforward term being set to perform feedforward control, the feedback term being set to perform feedback control, wherein when the control unit causes the converter to boost the output voltage, and when the feedforward term calculated by specified Expression I exceeds an upper limit calculated by specified Expression II, the control unit causes the converter to boost the voltage output from the fuel cell with the duty ratio including the upper limit and the feedback term.

A degradation detecting device for a fuel cell stack includes one or more sensors, a first detection module, a second detection module and a detection fusion module. The one or more sensors measure signals of two adjacent fuel cell groups to obtain a measurement of each of the two adjacent fuel cell groups. The first detection module detects a rate of change of deviation between the two measurements and generates a first detection result based on the detected rate of change of deviation. The second detection module detects a trending divergence between the two measurements and generates a second detection result based on the detected trending divergence. The detection fusion module fuses the first detection result and the second detection result to generate a final detection result of the fuel cell stack. A fuel cell system having the degradation detecting device and a managing method thereof are also disclosed.

Systems, methods, and devices of the various embodiments provide a hardware and software architecture enabling electrochemical impedance spectroscopy (EIS) to be performed on multiple electrochemical devices, such as fuel cells, at the same time without human interaction with the electrochemical devices and to use EIS to dynamically monitor the performance of a fuel cell system. Embodiment methods may include determining an impedance of a set of fuel cells using electrochemical impedance spectroscopy, determining an ohmic polarization of the set of fuel cells from the impedance, determining a concentration polarization of the set of fuel cells from the impedance, comparing the ohmic polarization of the set of fuel cells to a first threshold, comparing the concentration polarization of the set of fuel cells to a second threshold, and initiating a corrective action when the ohmic polarization is above the first threshold or when the concentration polarization is below the second threshold.

A fuel cell system that includes a first fuel cell that generates electric power using a hydrogen-containing fuel gas; a second fuel cell that generates electric power using off-gas exhausted from the first fuel cell and containing hydrogen that has not reacted in the first fuel cell; a first control device that controls the electric power output from the first fuel cell by adjusting a current or a voltage being output from the first fuel cell; a second control device that controls the electric power output from the second fuel cell by adjusting a current or a voltage being output from the second fuel cell; and an output control device that controls at least one of the first control device or the second control device such that a total electric power being generated by the first fuel cell and the second fuel cell approaches an electric power demand.