A method for starting a fuel cell and to a fuel cell system which is configured to carry out the method. The fuel cell includes electrically conductive bipolar plates, arranged between which there is in each case a cathode, including a fluid-conducting cathode space, a membrane and an anode, including a fluid-conducting anode space. There is provision that the method includes the following steps in the specified order: purging the anode space with a fluid in order to expel fuel, impressing electricity on a unit composed of the cathode (2k)/membrane (1)/anode (2a) by applying a current and/or a voltage, wherein the fluid is applied to the anode space or continues to be so, switching off the electricity, and introducing a fuel into the anode space.

A method for controlling a fuel cell system including a fuel cell, includes measuring an impedance of the fuel cell that includes a solid polymer electrolyte membrane to generate electric power via an electrochemical reaction between a fuel gas and an oxidant gas. An output electric current output from the fuel cell is increased to a threshold electric current value when the impedance is equal to or higher than a threshold impedance value and a target electric current value is larger than the threshold electric current value. The output electric current is maintained at the threshold electric current value. The output electric current is increased from the threshold electric current value to the target electric current value.

A method for controlling a fuel cell system including a fuel cell, includes generating electric current via an electrochemical reaction between a fuel gas and an oxidant gas by the fuel cell including a solid polymer electrolyte membrane. An impedance of the fuel cell is detected. It is determined whether the impedance reaches a threshold impedance. The electric current generated by the fuel cell is increased when the impedance is determined to reach the threshold impedance.

A fuel cell unit includes: a fuel cell stack including: a cell stack; a first terminal respectively disposed at a first end of the cell stack in the first direction; and a second terminal disposed at a second end of the cell stack in the first direction, an end plate disposed at a side opposite to the cell stack with respect to the first terminal; a power converter that converts output power of the fuel cell stack; a stack case that houses the fuel cell stack; a power converter case that houses the power converter and is fixed to the stack case; a first bus bar that electrically connects the first terminal and the power converter in the stack case and the power converter case; and a second bus bar that electrically connects the second terminal and the power converter in the stack case and the power converter case.

A fuel cell system includes: a reaction gas supply unit configured to supply a reaction gas to a fuel cell stack; a humidifier configured to transfer moisture from an off-gas discharged from the fuel cell stack to the reaction gas; and a controller configured to control the reaction gas supply unit so as to regulate a supply amount of the reaction gas, wherein the controller is configured to acquire a temperature of the humidifier and set the supply amount of the reaction gas based on a target power generation amount of the fuel cell stack, and in a case where the temperature of the humidifier is equal to or lower than a prescribed warm-up determination value, the controller executes warm-up control to increase the supply amount of the reaction gas as compared with a case where the temperature of the humidifier is higher than the warm-up determination value.

A fuel cell system includes a fuel cell stack having a membrane electrode assembly and an internal reactant gas passage, a unit that detects or estimates an actual retained water quantity (R.W.Q.), and a power generation control unit having a normal-time mode, a normal-time drying mode and a stop-time drying mode. In the normal-time drying mode, the fuel cell stack is caused to generate electric power while being dried more than in the normal-time mode until the actual R.W.Q. is decreased to a target R.W.Q. In the stop-time drying mode, when the actual R.W.Q. is equal to or more than a flooding threshold at a time of detection of a system stop instruction, the fuel cell stack is caused to generate electric power while being dried more than in the normal-time drying mode until the actual R.W.Q. is decreased to a target R.W.Q.

A fuel cell system is disclosed, which includes an anode recirculation loop having a fuel cell stack for generating power, a flowmeter, a current sensor and a processor. The flowmeter is configured for measuring a fuel flow rate provided into the anode recirculation loop. The current sensor is configured for measuring a current drawn from the fuel cell stack. The processor is configured for determining a steam to carbon ratio in the anode recirculation loop based on the measured fuel flow rate and the measured current. The fuel cell system further includes a temperature sensor for measuring a temperature in the anode recirculation loop. The process is configured for determining the steam to carbon ration further based on the measured temperature. A method for operating the fuel cell system and a fuel cell power plant are also disclosed.

A method of cleaning power cells in an array of power cells, comprising coupling at least one first power cell to second power cells in an array of power cells and causing the second power cells to drive the at least one first power cell with a voltage to clean catalyst on the at least one first power cell.

A method of accelerating activation of a fuel cell stack includes repeating, a plurality of times, a process including: applying a specific cyclic voltammetric pulse of high current to the fuel cell stack for a designated time and maintaining shutdown of the fuel cell stack.

A fuel cell system includes an auxiliary machine to be connected to a fuel cell, warm-up power control means for controlling generated power of the fuel cell by adjusting power supplied to the auxiliary machine during the warm-up of the fuel cell, and IV characteristic estimation means for temporarily reducing the power supplied to the auxiliary machine and estimating an IV characteristic of the fuel cell on the basis of at least two pairs of current values and voltage values at that time during the warm-up of the fuel cell.