Provided is a method of controlling a fuel cell system having a fuel cell stack, a reformer configured to reform a raw fuel and supply the reformed raw fuel to the fuel cell stack, a fuel flow rate control unit configured to control a flow rate of the raw fuel supplied to the reformer, an air supply pipe configured to supply oxygen to the raw fuel, and a combustor configured to mix a cathode discharged gas and an anode discharged gas discharged from the fuel cell stack and combust the mixed gas. The method of controlling the fuel cell system includes detecting at least one of a current value generated from the fuel cell stack and an oxygen supply amount supplied from the air supply pipe; estimating a composition of the anode discharged gas on the basis of at least one of the current value and the oxygen supply amount; and controlling a temperature of the combustor by adjusting the flow rate of the raw fuel using the fuel flow rate control unit on the basis of the estimated composition of the anode discharged gas.

The invention discloses a method and device for detecting a leakage rate of a solid oxide fuel cell system on line. The method comprises steps of: cutting off fuel gas supply of an anode cavity, cutting off an exhaust line of the anode cavity and cutting off high-pressure air supply of a cathode cavity in the operation process of a solid oxide fuel cell; obtaining an open-circuit voltage and temperature of the solid oxide fuel cell; and determining a leakage rate of the solid oxide fuel cell system according to the open-circuit voltage and the temperature of the solid oxide fuel cell. Based on the technical solutions disclosed by the invention, the leakage rate of the solid oxide fuel cell system can be detected on line.

The invention relates to a fuel cell stack (10) having a plurality of fuel cells (20) which have an inlet-side cathode port (22), anode port (24) and coolant port (26) and an outlet-side cathode port (23), anode port (25) and coolant port (27), wherein the fuel cell stack (10) also has: two end plates (30, 31) between which the plurality of fuel cells (20) are arranged, wherein at least one of the end plates (30, 31) has inlet openings (32, 34, 36) and outlet openings (33, 35, 37) for a cathode gas, an anode gas and a coolant, which are each fluidically connected to the inlet-side and outlet-side cathode ports (22, 23), anode ports (24, 25) and coolant ports (26, 27), and at least one sensor (50) which is guided through at least one additional opening (39) in at least one of the end plates (30, 31) into one of the inlet-side or outlet-side cathode ports (22, 23), anode ports (24, 25) or coolant ports (26, 27). The invention also relates to a method for producing the fuel cell stack (10).

An air supply system, comprising at least two air blowers and at least two communication valves; wherein one air blower is connected to a main air passage through the corresponding communication valve; and at least one other is connected to a reformer air passage and a stack air passage through at least one other communication valve, respectively. At least two air blowers are provided to connect the at least two communication valves.

A method of operating a fuel cell power system includes providing a fresh hydrogen fuel to power modules that each contain a heater and a stack of fuel cells, providing a fuel exhaust containing hydrogen and water from the stack to a condenser, removing water from the fuel exhaust to generate a recycled fuel containing dewatered hydrogen, and pressurizing and recycling the recycled fuel output from the condenser to the power modules. The removed water may be vaporized in a stack cathode exhaust.

The invention relates to a fuel cell system (1) comprising an air compressor (5) which is used to compress an air mass flow (4) that is supplied to at least one fuel cell (3), and further comprising a cooling air path (19), via which a cooling air mass flow (7) is branched off from the compressed air mass flow (6). The cooling of the air compressor (5) in the fuel cell system (1) is further improved by an on-demand control (20) of the compressed cooling air mass flow (6).

The present invention relates to a determination device (1; 1′) for a fuel cell system (2; 2′) having a fuel cell stack (4), comprising a virtual moisture sensor (7) for recording predefined determination values and a computing unit (10) for calculating a moisture value in a cathode inlet region (5) upstream of a cathode section of the fuel cell stack (4) based on the recorded determination values. The invention further relates to a fuel cell system (2; 2′) having such a determination device (1; 1′), methods for determining the moisture value, a computer program product (11) and a storage means having a computer program product (11) stored thereon.

The fuel cell system according to one embodiment of the present invention includes the solid oxide fuel cell configured to generate power by receiving the supply of the cathode gas and the anode gas. The fuel cell system includes a discharging passage configured to discharge the cathode off-gas and the anode off-gas discharged by the fuel cell as discharged gas to the outside, a discharged-gas temperature detection unit configured to detect or estimate the temperature of the discharged gas discharged from the discharging passage, an air supplying unit configured to supply air to the discharging passage, and the control unit configured to control the air supply to be executed by an air supplying unit on the basis of the detected or estimated temperature.

A fuel cell system mounted in a mobile object is equipped with a bypass flow passage that establishes communication between an air compressor and an exhaust gas flow passage, and a valve that adjusts an amount of air supplied to the bypass flow passage. A control unit performs a process for increasing a flow rate of air caused to flow through the bypass flow passage, by controlling a drive amount of the air compressor and the opening degree of the valve, when an outside air temperature is equal to or lower than a threshold and a speed of the mobile object is equal to or lower than a determination speed. In the process, a flow rate of air at a first temperature that is lower than a second temperature that is equal to or lower than the threshold is larger than a flow rate of air at the second temperature.

A fuel cell system includes a plurality of fuel cell stacks, a power generation control unit that controls power generation of the plurality of fuel cell stacks based on a required power for the plurality of fuel cell stacks, and a refreshing control unit configured to perform a refreshing process of decreasing a voltage on the plurality of fuel cell stacks. The refreshing control unit performs the refreshing process on the first fuel cell stack when the required power changes from a state in which the required power is less than a first predetermined value to a state in which the required power is equal to or greater than the first predetermined value and when the required power is in a range which is equal to or greater than the first predetermined value and less than the second threshold value.