A fuel cell system includes: a fuel cell outputting generated power to an external load; a secondary battery outputting charged power to the external load; and a controller performing a first control that controls output power of the fuel cell and output power of the secondary battery such that the output power of the secondary battery has a ratio predetermined in accordance with an output demand from the external load, in the power supplied to the external load, the controller switches the first control to a second control when the output demand satisfies a predetermined condition with which the output power of the secondary battery is predicted to reach a limit value with the first control, the second control sets a target value of the output power of the fuel cell such that the output power of the secondary battery is smaller than that in the first control.

A vehicle includes first and second fuel-cell stacks, a first coolant circuit having conduit arranged to circulate coolant through the first fuel-cell stack, a second coolant circuit having conduit arranged to circulate coolant through the second fuel-cell stack, a heater in fluid communication with at least the first coolant circuit, and an isolation valve assembly configured to proportion a flow of coolant between the first and second coolant circuits. The isolation valve assembly includes valving. The valving has an isolation position in which the first and second circuits are isolated. The valving also has at least one mixing position in which the first and second circuits are in fluid communication.

An illustrative example controller for a fuel cell power plant includes at least one processor and memory associated with the processor. The processor is configured to control operation of the fuel cell power plant during an islanded mode of operation wherein the fuel cell power plant provides output power to a load. The processor is configured to control the operation of the fuel cell power plant in the islanded mode by adjusting a droop gain of the controller to change the output power of the fuel cell power plant in response to a change in demand from the load. While adjusting the droop gain, the processor is configured to maintain a portion of the demand from the load met by the output power of the fuel cell power plant within a predetermined allocation of islanded mode load sharing assigned to the fuel cell power plant, maintain a ramp up rate of the output power of the fuel cell power plant within a predetermined maximum ramp up capability of the fuel cell power plant, and maintain a frequency of the output power of the fuel cell power plant within a predetermined range.

A fuel cell vehicle is mounted with a fuel cell system including a fuel cell stack and a battery. The fuel cell vehicle controls operation of the fuel cell system with an ECU, to perform standby power generation from activation to when travel is allowed and to perform power generation during operation of the fuel cell vehicle after travel has been allowed. In an activation method, the power generation current is increased in accordance with a low-temperature efficiency rate during the power generation during operation, the battery is charged and the power generation current is increased in accordance with a standby current increase rate that is lower than the low-temperature efficiency rate during the standby power generation.

A fuel cell system includes a fuel cell stack, a plurality of injectors capable of adjusting a flow rate of anode gas supplied to the fuel cell stack, and an ECU causing the plurality of injectors to operate. The plurality of injectors include a main injector, and a BP injector that operates when power that exceeds a prescribed power generation amount is generated. The ECU performs an operational check of causing the BP injector to operate at least once and judging whether the BP injector is normal or abnormal, during a period from when the fuel cell system is activated to when the fuel cell system stops.

A fuel cell vehicle and a method for controlling power generation for the same are provided. The fuel cell includes a motor supplying driving power for driving the fuel cell vehicle, a fuel cell and a battery supplying electrical power for driving the motor, and a vehicle controller for operating the fuel cell in advance by predicting a shortage of discharge power of the battery by monitoring the discharge power of the battery.

A fuel cell system includes a fuel cell stack, a circulation circuit, a gas liquid separator section, a purge channel, a purge valve and an ECU. In a method of operating the fuel cell system at low temperature, after start-up of the fuel cell system, the ECU performs a freezing determination processing step of determining freezing or non-freezing of the gas liquid separator, and in the case where freezing of the gas liquid separator is determined in the freezing determination step, the ECU performs a freezing confirmation processing step of immediately opening the purge valve for predetermined time.

Methods and systems are provided for iron preformation in a redox flow battery. In one example, a method may include, in a first condition, discharging and then charging the redox flow battery, and in a second condition, charging the redox flow battery including preforming iron metal at a negative electrode of the redox flow battery, and thereafter entering an idle mode of the redox flow battery including adjusting one or more electrolyte conditions. In some examples, each of preforming the iron metal and adjusting the one or more electrolyte conditions may increase a battery charge capacity to greater than a threshold battery charge capacity.

A coolant injection controller for a fuel cell system, the coolant injection controller configured to actively control the flow of a coolant to a fuel cell assembly for cooling and/or hydrating the fuel cell assembly in response to a measure of fuel cell assembly performance, wherein the coolant injection controller is configured to provide for a first mode of operation if the measure of fuel cell assembly performance is below a predetermined threshold and a second mode of operation if the measure of fuel cell assembly performance is above the predetermined threshold, the first and second modes having different coolant injection profiles and wherein, in the first mode of operation, the coolant injection profile provides for control of the flow of coolant by alternating between at least two different injection flow rates.

During power reduction transitions of a fuel cell power plant, the excess electric energy generated by consumption of reactants is extracted, during one or more periods of time, by a voltage limiting device control (200) in response to a controller (185) as i) energy dissipated in a resistive auxiliary load or ii) as energy applied to an energy storage system (201) (a battery), in boost and buck embodiments. The controller operates the voltage limiting device control in response to the positive time derivative of the voltage of one or more of the fuel cells exceeding a predetermined limiting value.