A fuel cell system in which a fuel cell is coupled to a motor driving battery and a vehicular auxiliary machine is coupled to the motor driving battery via a first voltage converter, the fuel cell system including a fuel cell auxiliary machine coupled to the first voltage converter; and a second voltage converter that couples the fuel cell auxiliary machine to the fuel cell.

An electrochemical cell system and a method for operating an electrochemical cell is provided. The method including determining one of a power level, current level or a voltage level of the electrochemical cell, the electrochemical cell including at least one cell having an anode side and a cathode side, the electrochemical cell further having a water transport plate operably coupled to the cathode side. An oxidant pressure level is determined in the cathode side. A water pressure level is determined in the water transport plate. The active area of the at least one cell is changed by adjusting at least one of the oxidant pressure level or the water pressure level based at least in part on the determined power level, current level or voltage level.

Disclosed are self-powering biofuel cell and sensor devices, systems and techniques. In some aspects, a self-powered biosensing system includes an electronic circuit; an anode including an enzymatic layer electrically coupled to a power supply voltage terminal of the electronic circuit and configured to interact with an analyte in a fluid, such as glucose or lactate; and a cathode electrically coupled to a ground voltage terminal of the electronic circuit, where the electronic circuit is operable to control and use the electrical energy generated at the anode and cathode for powering the biosensing system and detecting a concentration of the analyte in the fluid.

A fuel cell system includes a fuel cell, a supply device configured to supply a cathode gas to the fuel cell; and a control unit configured to execute recovery processing of causing a catalyst of the fuel cell to recover from performance deterioration by lowering an output voltage of the fuel cell. The control unit is configured to, when the recovery processing that has been executed is completed, control the supply device to place the fuel cell in a power generation paused state while making a stoichiometric ratio of the cathode gas lower than a stoichiometric ratio of the cathode gas in a normal operation state that is a state before execution of the recovery processing.

A fuel-cell system at 540 VDC for powering an electrical load of a rotorcraft with a first fuel cell and a second fuel cell. Each fuel cell is configured identically and features a positive electrical node and a negative electrical node. Each fuel cell is configured to provide one half of the electrical load of the rotorcraft and one half of the voltage of the electrical load.

A method for repairing a fuel cell stack having a plurality of individual cells involves the steps of: a) identifying at least one degraded individual cell in the fuel cell stack; and b) deactivating the at least one degraded individual cell.

A vehicle system includes a motor, a first device connected to the motor and configured to supply the motor with power, a fuel cell connected to the first device and configured to charge the first device, a second device connected to the fuel cell, a first converter interposed between the fuel cell and the first device and configured to adjust a voltage from one of the fuel cell or the first device and to supply power to the other, a second converter interposed between the fuel cell and the second device and configured to adjust a voltage from the second device and to apply the adjusted voltage to the fuel cell, and a third converter interposed between the first device and the second device and configured to adjust a voltage from one of the first device or the second device and to supply power to the other.

A fuel cell system comprises a fuel cell, a switch control module and at least two switch modules; the switch modules each is coupled to a positive electrode and a negative electrode of the fuel cell, and comprises switch units; the switch units each comprises a switch; the switch comprises a control terminal, a current input terminal and a current output terminal; in at least one of the at least two switch modules, the switch unit further comprises a voltage division structure; the voltage division structure is coupled in series between the current input terminal and the positive electrode of the fuel cell, or, the voltage division structure is coupled in series between the current output terminal and the negative electrode of the fuel cell; the switch control module is respectively coupled to the control terminals of the switches of the at least two switch modules to respectively control on-off of the switches.

A fuel cell system is equipped with a fuel cell unit that is composed of a plurality of fuel cells including a first fuel cell and a second fuel cell, a first supply device and a second supply device that supply reactive gas to the first fuel cell and the second fuel cell respectively, and a control device that controls running of the first fuel cell and the second fuel cell and operation of the first supply device and the second supply device. The control device suspends electric power generation by the first fuel cell and drives the first supply device to hold an opening circuit voltage of the first fuel cell within a target range, and suspends electric power generation by the second fuel cell and stops driving the second supply device when an output P required of the fuel cell unit is equal to 0.

Systems and methods are provided for using fuel cell staging to reduce or minimize variations in current density when operating molten carbonate fuel cells with elevated CO.sub.2 utilization. The fuel cell staging can mitigate the amount of alternative ion transport that occurs when operating molten carbonate fuel cells under conditions for elevated CO.sub.2 utilization.