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 comprising (i) at least one fuel cell stack (30) comprising at least one intermediate-temperature solid oxide fuel cell, and having an anode inlet (41) and a cathode inlet (61) and (ii) a reformer (70) for reforming a hydrocarbon fuel to a reformate, and a reformer heat exchanger (160); and defining: an anode inlet gas fluid flow path from a fuel source (90) to said reformer (70) to said fuel cell stack anode inlet (41); a cathode inlet gas fluid flow path from an oxidant inlet (140, 140, 140) through at least one cathode inlet gas heat exchanger (110, 150) to said reformer heat exchanger (160) to said fuel cell stack cathode inlet (61); wherein said at least one cathode inlet gas heat exchanger (110, 150) is arranged to heat relatively low temperature cathode inlet gas by transfer of heat from at least one of (i) an anode off-gas fluid flow path and (ii) a cathode off-gas fluid flow path; wherein said reformer heat exchanger is arranged for heating said anode inlet gas from said relatively high temperature cathode inlet gas to a temperature T.sub.3 at the anode inlet that is below a temperature T.sub.1 at the cathode inlet; and wherein oxidant flow control means (200) for controlled mixing of low temperature oxidant from the or each oxidant inlet (140, 140, 140) with high temperature cathode inlet gas to control a temperature T.sub.1 at the cathode inlet (61) relative to a temperature T.sub.3 at the anode inlet (41) and at a level higher than T.sub.3.

Various embodiments of the present disclosure provide a fuel cell system configured to modulate the flow of oxidant through the fuel cell system to maintain a desired temperature at the fuel cell stack. The fuel cell system is configured to control the flow of oxidant to maintain the desired temperature in the fuel cell stack based on temperature measurements of fluid outside of the fuel cell stack.

Various embodiments of the present disclosure provide a fuel cell system configured to modulate the flow of oxidant through the fuel cell system to maintain a desired temperature at the fuel cell stack. The fuel cell system is configured to control the flow of oxidant to maintain the desired temperature in the fuel cell stack based on temperature measurements of fluid outside of the fuel cell stack.

A fuel cell system includes: a turbine including a changing mechanism that adjusts a pressure difference between an upstream pressure and a downstream pressure of the turbine, the turbine recovering at least a part of energy of the cathode off-gas using the pressure difference and assisting driving of the motor with the recovered energy; and a control unit configured to drive the changing mechanism to increase or decrease the recovered energy. The control unit acquires a correlation temperature correlated with a temperature of the cathode off-gas discharged from the turbine and performs freezing avoidance control of not setting the degree of opening to be equal to or less than a predetermined degree of opening when the correlation temperature is lower than a predetermined threshold temperature at which the turbine is able to become frozen.

A fuel cell system is provided that can operate continuously and appropriately when a water self-sustaining operation of the fuel cell system is difficult due to environmental conditions and operating conditions, etc. When a first water level corresponding to a water shortage in a condensed water tank is detected using a water level detector, a controller implements a water-saving mode where the output of a fuel cell is decreased regardless of the external power load and the amount of reforming water used is reduced. When it is determined using a cooling determination device during the water-saving mode that the exhaust gas cooling capability in a condenser brought about by a cooling medium is at least a prescribed value, the controller implements a water recovery mode where the output of the fuel cell is increased regardless of the external power load and the amount of condensed water recovered is increased.

A humidifier includes: moisture permeable members each having a tubular shape; a case housing the moisture permeable members; a first flow path portion in which one of cathode gas to be supplied to a fuel cell and cathode off-gas discharged from the fuel cell flows inside the moisture permeable members; a second flow path portion in which the other of the cathode gas and the cathode off-gas flows outside the moisture permeable members within the case; and a temperature sensitive member attached to at least one of the moisture permeable members, deformable in response to temperature, and deforming so as to decrease a gap between the moisture permeable members as the temperature decreases.

A fuel cell vehicle on which a fuel cell system including a fuel cell is mounted includes a discharge mechanism configured to discharge moisture, generated by the fuel cell, from the fuel cell system to an outside of the vehicle, a camera configured to capture an image outside the vehicle, and an electronic control unit configured to determine whether predetermined control based on an information obtained from the image and executed or stopped in response to a driving status or drive mode of the vehicle in an on-state of an ignition switch is being executed, and, when it is determined that the predetermined control is being executed, execute a low discharge process in which a discharge flow rate of water vapor that is discharged from the discharge mechanism to the outside of the vehicle is reduced as compared to when it is determined that the predetermined control is stopped.

A fuel cell cooling system includes an air temperature estimating unit, an air temperature sensor and an abnormality determining unit. The air temperature sensor senses an air detection temperature of the air that flows out of the air cooler and is supplied to the fuel cell. The air temperature estimating unit estimates an air estimation temperature of the air, based on a temperature of a refrigerant flowing into the air cooler, a power supply quantity of a power supplied to the circulation pump, a temperature of the air flowing into the air cooler and a flow volume of the air. The abnormality determining unit determines that a circulation flow volume of the refrigerant is in an abnormal state when the air detection temperature is higher than the air estimation temperature by a value greater than or equal to a predetermined value.

A fuel cell system includes: a fuel cell including an anode gas flow channel and a cathode gas flow channel and generating electricity from a hydrogen-containing anode gas of the anode gas flow channel and an oxygen-containing cathode gas of the cathode gas flow channel; an anode off-gas emission path through which an anode off-gas emitted from the anode gas flow channel flows; and a cathode off-gas emission path through which a cathode off-gas emitted from the cathode gas flow channel flows. After stoppage of generation of electricity by the fuel cell, gas purging is performed in which at least a part of the cathode off-gas emission path is purged with a hydrogen-containing gas having passed through a junction where the anode off-gas emission path and the cathode off-gas emission path meet each other. The hydrogen-containing gas contains at least either the anode gas or the anode off-gas.