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.

This invention concerns a fuel cell system (100a; 100b; 100c) comprising a fuel cell stack (1) having an anode portion (2) and a cathode portion (3), a reformer (4) for supplying reformed anode gas to the anode portion (2), and an exhaust gas burner (5) for burning anode exhaust gas from the anode portion (2) and/or cathode exhaust gas from the cathode portion (3), wherein the reformer (4) is arranged at least in sections annularly around the exhaust gas burner (5), wherein an inner wall portion of the reformer (4) is arranged completely or at least substantially around an outer wall portion of the exhaust gas burner (5). The invention also concerns a method for operating a fuel cell system conforming to the invention (100a; 100b; 100c) and a motor vehicle (1000) with a fuel cell system conforming to the invention (100a; 100b; 100c).

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 system has at least one fuel cell, an oxidant line, a compressor, an exhaust-air line, a turbine, which is arranged in the exhaust-air line and is coupled to the compressor, an anode-purging line, which is connected to the exhaust-air line and has an anode-purging valve, and a control unit. The fuel-cell system is characterized in that a temperature-detecting unit is arranged at a turbine input, or upstream of the turbine input, for detecting the temperature of exhaust air flowing into the turbine, in that a pressure-detecting unit is coupled at least to the turbine input or a component lying upstream and is designed to detect a pressure of the exhaust air flowing into the turbine, in that the control unit is designed to ascertain a momentary mass flow of the exhaust air from the measured temperature of the exhaust air, the pressure upstream of the turbine and a specified turbine characteristic map, and in that the control unit is designed to activate the compressor and/or the turbine so as to achieve a minimum mass flow of the exhaust air.

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.

A recirculation fuel cell device, which can be utilized on a submarine, may include a fuel cell with an anode side and a cathode side, wherein both the anode and cathode sides have input and output sides. The device may include a first inlet for oxygen and a second inlet for hydrogen. The device may further include a cathode-side connection between the output side of the cathode side and the input side of the cathode side, and an anode-side connection between the output side of the anode side and the input side of the anode side. A water separator may be disposed in the cathode-side connection, and a gas discharge valve for a continuous release of process gases may be disposed on the output side of the cathode side of the fuel cell. Operation of the device may involve recirculating an anode gas stream in its entirety.

The present invention is concerned with improved fuel cell systems and methods. The present invention provides an intermediate-temperature solid oxide fuel cell (IT-SOFC) system comprising: (i) at least one fuel cell stack comprising at least one intermediate-temperature solid oxide fuel cell, and having an anode inlet, a cathode inlet, an anode off-gas outlet, a cathode off-gas outlet, and defining separate flow paths for flow of anode inlet gas, cathode inlet gas, anode off-gas and cathode off-gas; and (ii) a steam reformer for reforming a hydrocarbon fuel to a reformate, and having a reformer inlet for anode inlet gas, a reformer outlet for exhausting anode inlet gas, and a reformer heat exchanger; and defining: (a) an anode inlet gas fluid flow path from a fuel source to said steam reformer to said at least one fuel cell stack anode inlet; (b) an anode off-gas fluid flow path from said at least one fuel cell stack anode off-gas outlet to a fuel cell system exhaust; (c) a cathode inlet gas fluid flow path from an at least one oxidant inlet to said reformer heat exchanger to said at least one fuel cell stack cathode inlet; and (d) a cathode off-gas fluid flow path from said at least one fuel cell stack cathode off-gas outlet to said fuel cell system exhaust; wherein said reformer heat exchanger is a parallel-flow heat exchanger in fluid flow communication with (i) said at least one oxidant inlet and said at least one fuel cell stack cathode inlet, and (ii) said fuel source and said at least one fuel cell stack anode inlet, and is arranged for exchanging heat between said cathode inlet gas and said anode inlet gas.

A coolant bypass structure includes a main loop forming a channel in which coolant circulates; a bypass loop connected to the main loop and forming a selective bypass channel; and a stack bypass valve provided between the main loop and the bypass loop to open and close the bypass loop according to a predetermined temperature, and provided with an outlet temperature sensor. The coolant bypass structure may improve marketability by decreasing the starting time of the fuel cell vehicle in a frozen state and improve power efficiency.

A fuel cell system includes a mass flow rate measuring unit, an oxygen consumption mass flow rate acquiring unit, an exhaust-side air temperature acquiring unit, and an exhaust-side air humidity estimating unit. The mass flow rate measuring unit measures a first mass flow rate of intake-side air and a second mass flow rate of exhaust-side air. The oxygen consumption mass flow rate acquiring unit acquires a mass flow rate of oxygen consumption. The exhaust-side air humidity estimating unit estimate humidity in the exhaust-side air, on the basis of a difference between a flow rate of intake gas in the fuel cell system and a flow rate of exhaust gas from the fuel cell system, and the mass flow rate of the oxygen consumption.

In fuel cell system, exhaust material M exhausted from a fuel cell stack flows through the exhaust pipe. The gas-liquid separator is provided at the exhaust pipe and separates the exhaust material M into gas and liquid. The connecting pipe is connected to an exhaust port of the gas-liquid separator. The pressure regulating valve is connected to the connecting pipe and regulates pressures of the gas such that a pressure of the gas at an upstream side is higher than atmospheric pressure. The guide pipe is connected at the downstream side of the pressure regulating valve and guides at least the gas toward the exhaust pipe. The heat exchange unit exchanges heat between the exhaust pipe and the guide pipe.