A fuel cell system is disclosed. The fuel cell system includes: a fuel cell module including a plurality of unit cells for generating electrical energy by using oxygen of air and hydrogen of a reformed fuel gas; a first module including a burner part which burns an unreacted fuel gas and air discharged from the fuel cell module, an air-heating part which heats air through heat exchange with a hot combustion gas and a flame generated by the burner part and supplies the heated air to the fuel cell module, and a water vapor generation part which converts water, flowing through an inner portion thereof, into water vapor through heat exchange with a hot combustion gas generated by the burner part; and a second module which mixes a fuel supplied from an external fuel supply source and water vapor supplied from a water-vapor generator part.

A fuel cell hot box for improving the system efficiency of a fuel cell. Fuel cell stack parts, an after burner, a reformer, an air pre-heating zone, and a fuel-heat exchanger are provided in a housing allowing heat of the fuel cell stack parts and heat of combustion gas generated in the after burner to be used for reforming, preheating fuel and preheating air at the same time to avoid wasting energy. The fuel cell stack parts under thermal stress can be cooled to improve durability of the stack parts to increase a lifetime of a total system, and the stack parts can share the central chamber part to simplify a structure of the fuel cell hot box. In addition, the reformer includes an opening and closing unit to properly distribute the high-temperature combustion gas so that a reforming ratio is adjustable according to an operating condition of the fuel.

A fuel cell system (200) and a method (900) for controlling temperature of a heat transfer fluid in a fuel cell system (200). The system (200) comprising at least one fuel cell stack (205) comprising at least one fuel cell, and having an anode inlet, an anode off-gas outlet for flow of anode off-gas. The system (200) further comprising a first heat exchanger (215) coupled to receive the anode off-gas which has been output form the anode off-gas outlet, the first heat exchanger (215) configured to exchange heat between the anode off-gas and a heat transfer fluid to cool the anode off-gas and heat the heat transfer fluid. The system (200) further comprising a second heat exchanger (230) that is configured to provide heat to the heat transfer fluid and a heat removal region (235) that is configured to remove heat from the heat transfer fluid. The system (200) further comprising a pump (240) configured to pump the heat transfer fluid around a fluid circuit (225) in a flow direction of: heat removal region (235) where thermal energy is removed, second heat exchanger (230) where thermal energy is added, first heat exchanger (215) where thermal energy is added. The method (900) comprises controlling (920, 945) the pump speed and controlling (925, 940) a mass flow rate of a medium to control the rate of heat removal in the heat removal region (235).

Electrochemical systems for distributed energy generation, comprising protonic ceramic fuel cells (PCFCs), are provided. The systems of the present invention allow for operation at lower stack temperatures than current solid oxide fuel cell (SOFC) systems. These systems can achieve various advantages and benefits over SOFC systems, such as higher fuel utilization, improved cell voltage, and air ratio optimization.

A hybrid powerplant can include a fuel cell cycle system configured to generate a first power using a fuel and an oxidizer. The powerplant can also include a supercritical carbon dioxide (sCO.sub.2) cycle system operatively connected to the fuel cell cycle to receive heat from the fuel cell cycle to cause the sCO.sub.2 cycle system to generate a second power.

A fuel cell system includes a fuel cell, a regenerator, an oxidant feed path, a gas discharge path, and a heat exchanger. The fuel cell includes an anode and a cathode and reduces a mediator with the cathode. The regenerator oxidizes, with an oxidant, the mediator reduced by the cathode. Through the oxidant feed path, the oxidant is guided to the regenerator. Through the gas discharge path, the gas present inside the regenerator is guided out of the regenerator. The heat exchanger heats the oxidant by exchanging heat between the oxidant flowing in the oxidant feed path and the gas flowing in the gas discharge path.

A fuel cell system includes a fuel cell module and an oxidant gas temperature adjustment device for adjusting a temperature of an oxidant gas supplied to the fuel cell module. The fuel cell module includes a first fuel cell and a second fuel cell. The first fuel cell is at least configured to reform a fuel gas. The fuel cell system includes a temperature control unit for setting a target temperature of the oxidant gas supplied to the fuel cell module such that a temperature of the first fuel cell and a temperature of the second fuel cell do not exceed a prescribed upper-limit temperature and controlling the oxidant gas temperature adjustment device based on of the target temperature, and the temperature control unit calculates the target temperature.

A fuel cell single unit including: a fuel cell element in which an anode layer and a cathode layer are formed so as to sandwich an electrolyte layer; a reducing gas supply path for supplying a gas containing hydrogen to the anode layer; an oxidizing gas supply path for supplying a gas containing oxygen to the cathode layer; and an internal reforming catalyst layer, which has a reforming catalyst for steam-reforming a fuel gas, in at least a part of the reducing gas supply path is provided. An external reformer, which has a reforming catalyst for steam-reforming the fuel gas, is provided upstream of the reducing gas supply path, and the fuel gas partially reformed by the external reformer is supplied to the reducing gas supply path.

Provided are a metal plate configured such that sufficient strength and performance are ensured and the workability and cost of mass production are improved, and an electrochemical element and the like including the metal plate. A metal plate 1 includes a thick portion 110, and a thin portion 120 that is thinner than the thick portion 110. The thin portion 120 is provided with a penetration space 1c passing through the thin portion 120 in the thickness direction.

The invention provides a hybrid power system, which integrates an internal combustion engine with a solid oxide fuel cell (SOFC) stack and provides power for the vehicle through the internal combustion engine at first in the preheating stage of the SOFC stack, thereby solving the problem that an SOFC stack is unable to provide power for the vehicle in the preheating stage. At the same time, the internal combustion engine burns fuel gas, outputs high temperature exhaust gas, heats the heat exchanger with the high temperature exhaust gas, then discharges the exhaust gas from an exhaust turbine and inhales air from the outside of the system. The air first passes through an air preheater, then passes through a heat exchanger and then enters the inside of the SOFC stack, preheats the air preheater through an air pipeline and then is discharged. After multiple cycles, the preheating of the SOFC stack is completed. As the air preheater is connected to the heat exchanger in series to heat the air, the heating speed of the air entering the SOFC stack is raised, the preheating time is shortened and a quick start of the SOFC stack is achieved so that the SOFC stack can be used to achieve the purpose of providing power for the vehicle efficiently.