This fuel cell stack activation method is a method for activating a fuel cell stack provided with a solid polymer-containing electrolyte membrane, an anode electrode, and a cathode electrode, the method comprising: a first current application step for applying a current by electrically connecting the two electrodes via an external electrical load in a state in which a potential difference is generated between the two electrodes by supplying air as a cathode-side gas to the cathode electrode while supplying hydrogen gas as an anode-side gas to the anode electrode; and a second current application step for applying a current by electrically connecting the two electrodes via an external electrical load in a state in which a potential difference is generated between the two electrodes by supplying nitrogen gas as a cathode-side gas to die cathode electrode while supplying hydrogen gas as an anode-side gas to the anode electrode.

A method for controlling a fuel cell system including a fuel cell which includes an anode electrode and a cathode electrode sandwiching a solid polymer electrolyte membrane therebetween, includes driving a pump to supply an oxidant gas to the cathode electrode. The pump has a minimum supply amount of the oxidant gas. A fuel gas is supplied to the anode electrode to generate electric power via an electrochemical reaction between the fuel gas and the oxidant gas. It is determined whether a target amount of the oxidant gas to be supplied to the cathode electrode is lower than the minimum supply amount. An opening degree of a pressure adjusting valve is adjusted to adjust an amount of the oxidant gas supplied to the cathode electrode to be the target amount when the target amount is determined to be lower than the minimum supply amount.

A method of shutting down operation of a fuel cell system is disclosed, comprising a fuel cell stack, the method comprising the sequential steps of: i) ceasing a supply of fuel to the fuel cell stack; ii) closing a shut-off valve on an exhaust line in fluid communication with a cathode system of the fuel cell system, the cathode system comprising a cathode fluid flow path passing through the fuel cell stack; iii) pressurizing the cathode system with an air compressor in fluid communication with a cathode air inlet port in the fuel cell stack; and iv) ejecting water from the cathode flow path.

A fuel cell device includes a solid oxide fuel cell; an air-tight housing accommodating the solid oxide fuel cell; a gas concentration detector detecting a gas concentration of a combustible stagnant gas; and a controller performing an emergency stop by instantly stopping the supply of the fuel to the fuel electrode when the gas concentration is higher than an upper limit concentration and performing a normal stop by lowering a temperature of the fuel cell device while supplying the fuel to the fuel electrode when the gas concentration is not higher than the upper limit concentration and the gas concentration is higher than a predetermined concentration.

A control unit of an aging apparatus performs a first pattern of supplying a humidified H.sub.2 gas to an anode and supplying a humidified N.sub.2 gas to a cathode, to thereby move protons from the anode to the cathode through an electrolyte membrane. Further, the control unit performs a second pattern of supplying the humidified N.sub.2 gas to the anode and supplying the humidified H.sub.2 gas to the cathode, to thereby move protons from the cathode to the anode through the electrolyte membrane.

A method for performing one or more proactive remedial actions to prevent anode flow-field flooding in an anode side of a fuel cell stack at low stack current density. The method includes identifying one or more trigger conditions that could cause the anode flow-field to flood with water, and performing the one or more proactive remedial actions in response to the identified trigger conditions that removes water from the anode side flow-field prior to the anode flooding occurring.

A fuel cell system including a fuel cell, an off-gas reprocessing unit that is provided downstream of the fuel cell and that at least partially removes at least one of steam or carbon dioxide from an off-gas discharged from the fuel cell, a flow passage that is provided downstream of the off-gas reprocessing unit and that allows a reprocessed off-gas discharged from the off-gas reprocessing unit to flow therethrough, and a controlling unit that modulates the reaction constant K.sub.pa of a reaction A with respect to the reprocessed off-gas discharged from the off-gas reprocessing unit, to 1.22 or more.

A fuel cell system includes a fuel cell module having an anode having an anode inlet configured to receive anode feed gas and an anode outlet configured to output anode exhaust into an anode exhaust conduit. The fuel cell module further includes a cathode having a cathode inlet configured to receive cathode feed gas and a cathode outlet. The fuel cell system also includes an anode exhaust processing system fluidly coupled to the anode exhaust conduit and a gas injection system disposed downstream of the anode inlet and upstream of the anode exhaust processing system. The gas injection system is configured to inject a gas within the anode exhaust conduit to prevent an under-pressurization condition of the anode.

An apparatus for inspecting a stack assembly including a fluid channel through which fluid is supplied into fuel cell stacks includes a frame, a conveyor that is installed in the frame and that carries the stack assembly in a predetermined direction of movement to locate the stack assembly in a predetermined inspection position, a masking mechanism that is installed in the frame and that masks a fluid inlet and a fluid outlet of the stack assembly to seal the fluid channel of the stack assembly from outside the stack assembly, and a gas injection mechanism that is installed in the frame and that injects an inspection gas into the fluid channel of the stack assembly to inspect a sealing state of the fluid channel in the stack assembly, in a state in which the stack assembly is sealed by the masking mechanism.

A fuel cell system 1 is provided with a fuel cell 10 provided with an air passage 10a, an air inflow path 21, an air outflow path 23, a compressor 22, a pressure regulating valve 24, a bypass passage 27, and a bypass valve 28. A first threshold value is calculated based on an FC inlet pressure-lower limit value. When it is judged that an FC inlet pressure-command value is lower than the first threshold value, feedback control of the opening degree of the pressure regulating valve is suspended without suspending feedback control of the opening degree of the bypass valve if it is judged that the FC pressure loss-lower limit value is larger than the bypass pressure loss-lower limit value, and feedback control of the opening degree of the bypass valve is suspended without suspending feedback control of the opening degree of the pressure regulating valve if it is judged that the bypass pressure loss-lower limit value is larger than the FC pressure loss-lower limit value.