An onboard electrochemical system of an electrochemical cell including a cathode and an anode separated by an electrolyte separator is selectively operated in either of two modes. In a first mode of operation, water or air is directed to the anode, electric power is provided to the anode and cathode to provide a voltage difference between the anode and the cathode, and nitrogen-enriched air is directed from the cathode to an aircraft fuel tank or aircraft fire suppression system. In a second mode of operation, fuel is directed to the anode, electric power is directed from the anode and cathode to one or more aircraft electric power-consuming systems or components, and nitrogen-enriched air is directed from the cathode to a fuel tank or fire suppression system.

The fuel cell system of the present disclosure includes: a fuel cell that includes a membrane electrode assembly including a proton conducting ceramic electrolyte membrane, a cathode disposed on a first surface of the electrolyte membrane, and an anode disposed on a second surface of the electrolyte membrane, the fuel cell generating electric power through an electrochemical reaction using a fuel gas and an oxidant gas; a power source that applies a voltage to the fuel cell; and a controller. In a shutdown process, the controller controls the power source to apply the voltage to the fuel cell such that a terminal voltage of the fuel cell is equal to or higher than an open circuit voltage of the fuel cell.

Based on an operation condition ?(t) of a polymer electrolyte fuel cell at a time t, the concentration distribution of a radical generation ion and the concentration distribution of a radical scavenging ion in an electrolyte membrane are estimated. Next, a load command p(t+?t) at a time (t+?t) is acquired. Next, a reference operation condition ?.sup.ref(t+?t) under which the load command p(t+?t) can be realized is acquired. Next, whether or not a judgment index exceeds a first threshold value ?.sub.1 is judged. When the judgment index exceeds ?.sub.1, an operation condition which is different from ?.sup.ref(t+?t) and gives the judgment index of ?.sub.1 or less is selected as ?(t+?t). On the other hand, when the judgment index does not exceed ?.sub.1, ?.sup.ref(t+?t) is selected as ?(t+?t). The fuel cell system has a control device for performing such treatments.

A fuel battery system includes a fuel battery, an electric storage, a voltage adjuster, a pump, an abnormity detector, and circuitry. The fuel battery generates electricity using fuel gas and oxidant gas. The voltage adjuster is connected to at least one of the fuel battery and the electric storage. The voltage adjuster is configured to adjust voltage output from the fuel battery or the electric storage to output the adjusted voltage to a load. The pump supplies the oxidant gas to the fuel battery using electric power output from at least one of the fuel battery and the electric storage. The voltage adjuster is connected between the fuel battery and the pump. The abnormity detector detects abnormity in the voltage adjuster. The circuitry is configured to restrict the electric power supplied to the pump in a case where the abnormity detector detects the abnormity in the voltage adjuster.

A fuel cell power controller tracks load current and fuel cell output voltage, and alerts on excessive fuel cell ramp rate, so another power source can supplement the fuel cell and/or the load can be reduced. A power engineering process makes efficient use of available fuel cell power by ramping up power flow rapidly when power is available, while respecting the ramp rate and other power limitations of the fuel cell and safety limitations of the load. Power flow decreases after an alert indicating an electrical output limitation of the fuel cell. Permitted power flow increases in response to a power demand increase (actual or requested) from the load in the absence of the alert. Power flow may increase or decrease in a fixed amount, a proportional amount, or per a sequence. A power controller relay may trip open on a low fuel cell output voltage or high load current.

A method for synchronizing voltages of a fuel cell vehicle may synchronize the voltages of high voltage components in real time regardless of the completion of vehicle start-up in order to improve performance and control precision within a full range of operable voltages. The method includes a default voltage synchronization step in which, when the fuel cell vehicle starts, the voltages of the high voltage components are corrected based on an offset value, stored in advance in multiple auxiliary controllers for controlling the high voltage components, and the corrected voltages are further corrected according to a default voltage synchronization command of a main controller; and a real-time voltage synchronization step in which, after the default voltage synchronization step, the main controller transmits a target offset value to the auxiliary controllers, and the auxiliary controllers correct the voltages based on the target offset value.

A method is described for regulating the platinum oxide fraction in a catalyst layer of a fuel cell of a fuel cell stack for a motor vehicle, involving the steps: model-based determination of a present fraction of platinum oxide in dependence on a present operating state; determination of the electrical potential and/or a change in potential in dependence on the present fraction of platinum oxide; adapting the fraction of platinum oxide in dependence on an anticipated and/or demanded operating state of the fuel cell and/or of the vehicle.

A vehicle power system including a fuel cell auxiliary power unit for providing clean, efficient power to a vehicle. The system generally includes a fuel cell with a first

DC output and a heat output, a pressure vessel adapted to contain and provide pressurized hydrogen to the fuel cell, an electrical storage unit with a DC input coupled to the first DC output of the fuel cell. The electrical storage unit also has a second DC output. An inverter is coupled to the second DC output of the electrical storage unit to receive power, the inverter having a first AC output. The system can provide heat, AC power, and DC power to the vehicle.

The disclosure relates to a method for operating a fuel cell that comprises at least one individual cell with a membrane and catalysts, wherein humidity within the fuel cell is actively influenced as a function of a voltage of the fuel cell, and the method further includes specifying an initial humidity at an initial operating-point-related voltage, and specifying a second humidity that is lower than the first humidity at a second operating-point-related voltage that is higher than the first operating-point-related voltage. Furthermore, the disclosure relates to a fuel cell system that is configured to perform the method according to the disclosure.

A fuel cell power controller tracks load current and fuel cell output voltage, and alerts on excessive fuel cell ramp rate, so another power source can supplement the fuel cell and/or the load can be reduced. A power engineering process makes efficient use of available fuel cell power by ramping up power flow rapidly when power is available, while respecting the ramp rate and other power limitations of the fuel cell and safety limitations of the load. Power flow decreases after an alert indicating an electrical output limitation of the fuel cell. Permitted power flow increases in response to a power demand increase (actual or requested) from the load in the absence of the alert. Power flow may increase or decrease in a fixed amount, a proportional amount, or per a sequence. A power controller relay may trip open on a low fuel cell output voltage or high load current.