A control method for a fuel cell stop mode is provided. The method includes measuring an air flow rate supplied to a fuel cell stack and when a fuel cell stop mode is entered, determining an oxygen distribution state between cells included in the fuel cell stack based on the measured air flow rate. Air supply is then supplied to the fuel cell stack or the air supply to the fuel cell stack is interrupted based on the determined oxygen distribution state.

A control method for a fuel cell stop mode is provided. The method includes measuring an air flow rate supplied to a fuel cell stack and when a fuel cell stop mode is entered, determining an oxygen distribution state between cells included in the fuel cell stack based on the measured air flow rate. Air supply is then supplied to the fuel cell stack or the air supply to the fuel cell stack is interrupted based on the determined oxygen distribution state.

A method of distributing power in a fuel cell system including a plurality of fuel cell stacks, includes determining, by a controller, a total system power demand, which is a power demand of the fuel cell system, determining an operation order of the fuel cell stacks based on a state of the fuel cell stacks, determining the number of operation fuel cell stacks among the plurality of fuel cell stacks based on the total system power demand and an average available power of the fuel cell stacks, determining operation target fuel cell stacks based on the operation order of the fuel cell stacks and the number of operation fuel cell stacks, and determining a power demand of each of the operation target fuel cell stacks based on the total system power demand and an effective catalyst reaction area ratio of each fuel cell stack included in the operation target fuel cell stacks.

A fuel cell system includes a plurality of fuel cell units each configured to generate lower-voltage DC power. The fuel cell system includes a plurality of DC-DC converters each electrically connected to each of the fuel cell units and configured to convert the lower-voltage DC power to higher-voltage DC power. The fuel cell system includes a primary load power conversion unit electrically connected to the plurality of DC-DC converters and configured to output a primary load. The fuel cell system includes an auxiliary load power conversion unit electrically connected to the plurality of DC-DC converters and configured to output an auxiliary load.

A fuel cell system that includes a fuel cell that generates electricity through an electrochemical reaction between a fuel gas and an oxidant gas, and a control portion that determines whether there is leakage of the fuel gas. The control portion has start means for starting the fuel cell by raising the voltage of the fuel cell from a starting voltage to an operation voltage that is lower than an open-circuit voltage, and leakage determination means for determining whether there is leakage of the fuel gas before the voltage of the fuel cell reaches the operation voltage when the fuel cell is started.

A redox battery energy storage system including multiple energy storage stacks having multiple reactor cells is disclosed. Each of the energy storage stacks may include an integrated DC/DC converter configured to convert an output voltage of the stacks to a higher output voltage. The output of the DC/DC converts may be coupled in parallel to an energy storage system output bus. By configuring the energy storage system in this manner, inefficiencies and losses caused by shunt electrical currents in the systems may be decreased.

A redox battery energy storage system including multiple energy storage stacks having multiple reactor cells is disclosed. Each of the energy storage stacks may include an integrated DC/DC converter configured to convert an output voltage of the stacks to a higher output voltage. The output of the DC/DC converts may be coupled in parallel to an energy storage system output bus. By configuring the energy storage system in this manner, inefficiencies and losses caused by shunt electrical currents in the systems may be decreased.

The invention relates to a fuel cell system (2) with at least one fuel cell stack (19), which comprises an anode chamber (20) and a cathode chamber (21), with at least one air conveying device (3) for the supply of the cathode chamber (21) with air via a feed air line (22), with an outlet air line (23) from the cathode chamber (21), with at least one fuel supply device (26) for the supply of the anode chamber (20) with fuel, with at least one anode circuit (28) for the recirculation of unused fuel around the anode chamber (20), furthermore with a cathode bypass (37). The fuel cell system according to the invention is characterized in that the cathode bypass line (37) branches off from the feed air line (22) upstream of or in the region of a valve device (35) in said feed air line (22), and opens into the outlet air line downstream of or in the region of a further valve device (36) in said outlet air line (23), wherein a gas jet pump (38) which can be driven by the air which flows around the cathode chamber (21) is arranged in the cathode bypass (37), which gas jet pump (38) is connected switchably on the suction side to the anode chamber (20) and/or the cathode chamber (21).

A method of operating a fuel cell assembly comprising a plurality of fuel cells connected together for collectively providing power to a load, each fuel cell including an anode and a cathode, the method comprising selectively providing an electrical connection between the anode and the cathode of at least one of the fuel cells of the assembly for lowering the voltage across the fuel cell independent of the load.

A cooling circuit for a fuel cell includes at least one channel, a mechanical support, a first sensor, and a second sensor. Each channel is formed in a bipolar plate of the fuel cell, and is adapted to permit a cooling fluid to flow. The first sensor senses a flow rate of the cooling fluid. The second sensor senses an electrical conductivity of the cooling fluid. Both the first sensor and the second sensor are installed on the mechanical support.