An example fuel cell stack component includes a metallic layer applied to the component and an oxide layer applied to the metallic layer. The oxide layer includes a chemical component that is not in the metallic layer.

A unit cell includes an air inlet/outlet that is formed on a frame unit rather than being installed in a fuel electrode (anode) to simplify a sealing process, and accordingly, a continuous process using a tape casting technique may be performed. In addition, an electrolyte material that is in contact with an air electrode (cathode) in the frame unit is optimized to improve ion conductivity and a porosity of an upper layer material of the fuel electrode unit is optimized to increase fuel diffusion from a gas channel to an electrolyte layer. In addition, a sealing process performed inside the unit cell or between the unit cells of the stack is stabilized and strongly maintained, and thus a fuel cell using the unit cell and the stack disclosed herein may have excellent economic feasibility and high energy efficiency.

A unit cell includes an air inlet/outlet that is formed on a frame unit rather than being installed in a fuel electrode (anode) to simplify a sealing process, and accordingly, a continuous process using a tape casting technique may be performed. In addition, an electrolyte material that is in contact with an air electrode (cathode) in the frame unit is optimized to improve ion conductivity and a porosity of an upper layer material of the fuel electrode unit is optimized to increase fuel diffusion from a gas channel to an electrolyte layer. In addition, a sealing process performed inside the unit cell or between the unit cells of the stack is stabilized and strongly maintained, and thus a fuel cell using the unit cell and the stack disclosed herein may have excellent economic feasibility and high energy efficiency.

A high-temperature fuel cell system includes a reformer that reforms a hydrocarbon-based raw fuel to generate a reformed gas containing hydrogen, a fuel cell that generates power by using the reformed gas and an oxidant gas, and a burner that heats the reformer. The burner includes an anode-off-gas gathering portion that has an anode-off-gas ejection hole and at which an anode off-gas discharged from an anode of the fuel cell gathers. The anode-off-gas gathering portion surrounds a first cathode-off-gas passing area through which a cathode off-gas discharged from a cathode of the fuel cell passes. The anode-off-gas ejection hole is formed such that the anode off-gas ejected upward from the anode-off-gas ejection hole approaches the cathode off-gas passing upward through the first cathode-off-gas passing area. The anode off-gas ejected from the anode-off-gas ejection hole and the cathode off-gas that has passed through the first cathode-off-gas passing area are burned.

A high-temperature fuel cell system includes a reformer that reforms a hydrocarbon-based raw fuel to generate a reformed gas containing hydrogen, a fuel cell that generates power by using the reformed gas and an oxidant gas, and a burner that heats the reformer. The burner includes an anode-off-gas gathering portion that has an anode-off-gas ejection hole and at which an anode off-gas discharged from an anode of the fuel cell gathers. The anode-off-gas gathering portion surrounds a first cathode-off-gas passing area through which a cathode off-gas discharged from a cathode of the fuel cell passes. The anode-off-gas ejection hole is formed such that the anode off-gas ejected upward from the anode-off-gas ejection hole approaches the cathode off-gas passing upward through the first cathode-off-gas passing area. The anode off-gas ejected from the anode-off-gas ejection hole and the cathode off-gas that has passed through the first cathode-off-gas passing area are burned.

A high-temperature fuel cell system includes a fuel cell that includes an anode and a cathode and that generates power by using a fuel gas and an oxidant gas, a fuel-gas path along which the fuel gas flows, an oxidant-gas path along which the oxidant gas flows, an anode-off-gas path along which an anode off-gas flows, a cathode-off-gas path along which a cathode off-gas flows, a combustion space in communication with the anode-off-gas path and the cathode-off-gas path and in which the anode off-gas and the cathode off-gas are burned, a flue-gas path along which a flue gas flows, a cathode-off-gas branch portion disposed on the cathode-off-gas path between the combustion space and the cathode and at which some of the cathode off-gas is branched from the cathode-off-gas path, and a first heat exchanger that enables heat exchange between the oxidant gas, the flue gas, and the cathode off-gas.

An onboard electrochemical system of an electrochemical cell including a cathode and an anode separated by an electrolyte separator is selectively operated in either of two modes. In a first mode of operation, water or air is directed to the anode, electric power is provided to the anode and cathode to provide a voltage difference between the anode and the cathode, and nitrogen-enriched air is directed from the cathode to an aircraft fuel tank or aircraft fire suppression system. In a second mode of operation, fuel is directed to the anode, electric power is directed from the anode and cathode to one or more aircraft electric power-consuming systems or components, and nitrogen-enriched air is directed from the cathode to a fuel tank or fire suppression system.

An onboard electrochemical system of an electrochemical cell including a cathode and an anode separated by an electrolyte separator is selectively operated in either of two modes. In a first mode of operation, water or air is directed to the anode, electric power is provided to the anode and cathode to provide a voltage difference between the anode and the cathode, and nitrogen-enriched air is directed from the cathode to an aircraft fuel tank or aircraft fire suppression system. In a second mode of operation, fuel is directed to the anode, electric power is directed from the anode and cathode to one or more aircraft electric power-consuming systems or components, and nitrogen-enriched air is directed from the cathode to a fuel tank or fire suppression system.

A high-temperature operating fuel cell system includes a reformer that produces a reformed gas from air and a raw material, an air supplier that supplies the air to the reformer, a fuel cell that generates electricity with the reformed gas and air, a combustor in which unutilized portions of the reformed gas and the air burn, a combustion exhaust gas path of a combustion exhaust gas, a depurator including a combustion catalyst for freeing the combustion exhaust gas of toxic substances, a heater that heats the combustion catalyst, and a controller. At start-up in a case of having detected an abnormal stoppage in which a purge operation is impossible, the controller first controls the heater so that the combustion catalyst is heated to a predetermined temperature and then controls the air supplier so that the high-temperature operating fuel cell system is purged by supplying the air to the reformer.

A high-temperature operating fuel cell system includes a reformer that produces a reformed gas from air and a raw material, an air supplier that supplies the air to the reformer, a fuel cell that generates electricity with the reformed gas and air, a combustor in which unutilized portions of the reformed gas and the air burn, a combustion exhaust gas path of a combustion exhaust gas, a depurator including a combustion catalyst for freeing the combustion exhaust gas of toxic substances, a heater that heats the combustion catalyst, and a controller. At start-up in a case of having detected an abnormal stoppage in which a purge operation is impossible, the controller first controls the heater so that the combustion catalyst is heated to a predetermined temperature and then controls the air supplier so that the high-temperature operating fuel cell system is purged by supplying the air to the reformer.