A fuel cell power generation system is provided with: at least one fuel cell module each of which includes a fuel cell having a fuel-side electrode, an electrolyte, and an oxygen-side electrode; at least one fuel supply line for supplying a fuel gas to the fuel-side electrode included in the at least one fuel cell module; at least one oxidizing gas supply line for supplying an oxidizing gas to the oxygen-side electrode included in the at least one fuel cell module; and a most downstream exhaust fuel gas line through which an exhaust fuel gas discharged from a most downstream module that is disposed most downstream in a flow of the fuel gas among the at least one fuel cell module flows. The most downstream exhaust fuel gas line is configured to supply the exhaust fuel gas to the oxygen-side electrode included in any of the fuel cell modules.

A fuel supply control system and method for a fuel cell are disclosed. The system includes: a fuel cell configured to receive a fuel gas and an oxidation gas and generate electric power; a recirculation line configured to circulate gas containing the fuel gas and connected to a fuel electrode of the fuel cell; a discharge valve provided in the recirculation line and configured to allow the gas to be discharged to the outside when open; a discharge amount estimator configured to estimate a discharge amount of the discharged gas based on a supply amount of the fuel gas supplied to the recirculation line, a consumption amount of the fuel gas consumed in the fuel cell, and a change in the amount of the gas in the recirculation line; an offset calculator configured to calculate the discharge amount of the gas estimated by the discharge amount estimator with the discharge valve closed, as a discharge offset; and a controller configured to control opening/closing of the discharge valve.

A fuel cell system includes: a reformer which generates a reformed gas containing hydrogen by reacting hydrocarbon and moisture with each other; a fuel cell stack which generates electric energy through electrochemical reaction of the reformed gas and an oxidant; an ejector which, using steam as a drive fluid, sucks either a raw fuel containing the hydrocarbon or a recycled gas recovered from an anode exhaust gas, and supplies a resultant gas to the reformer; and a vaporizer which generates the steam by vaporizing water, wherein an operation temperature of the fuel cell stack is higher than a boiling point of water at an operation pressure, and the vaporizer generates the steam through heat exchange with the anode exhaust gas.

An air pressure in fuel cells of an electric power generation system comprising a fuel cell stack (PCS) is raised with a pressurized air cooling system with recirculation to values at least two times greater than typical values for an PCS with air cooling. The FCS is either placed in a high-pressure chamber to which air is injected, or air outgoing from the FCS is redirected via a duct back to the FCS inlet and a portion of pressurized fresh air is added thereto. The chamber or the duct is provided with a radiator by means of which circulating air heat is transferred into the external environment. Air recirculation in the chamber or the duct is effected by means of fans for cooling fuel cells. Useful capacity of electric power generation systems based on fuel cells is raised significantly, the necessity of using a humidifier is excluded, and the temperature range of fuel cell operation is expanded.

The present disclosure relates to a fuel cell system including: an air supply line configured to supply air to a fuel cell stack; a discharge line connected to the fuel cell stack and configured to guide exhaust gas discharged from the fuel cell stack; a discharge adapter connected to the discharge line and configured to discharge the exhaust gas to the outside; and a bypass line having one end connected to the air supply line and the other end connected to the discharge adapter, the bypass line being configured to selectively allow the air to flow from the air supply line to the discharge adapter, thereby effectively reducing a hydrogen concentration in exhaust gas discharged from the fuel cell stack.

A fuel cell system mounted on a vehicle includes a fuel cell, a humidity sensor configured to detect a humidity in a vehicle cabin of the vehicle, a cathode off-gas exhaust passage through which cathode off-gas emitted from the fuel cell is exhausted to outside the vehicle, an introducing port for cathode off-gas, provided in the cathode off-gas exhaust passage, a cathode off-gas introducing unit configured to introduce cathode off-gas emitted from the fuel cell, into the vehicle cabin of the vehicle via the introducing port, and a cathode off-gas introducing amount control unit configured to control an amount of the cathode off-gas introduced into the vehicle cabin of the vehicle in accordance with a humidity in the vehicle cabin of the vehicle, detected by the humidity sensor.

A fuel cell system that generates electric power by supplying anode gas and cathode gas to a fuel cell includes a control valve adapted to control the pressure of the anode gas to be supplied to the fuel cell; a buffer unit adapted to store the anode-off gas to be discharged from the fuel cell; a pulsation operation unit adapted to control the control valve in order to periodically increase and decrease the pressure of the anode gas at a specific width of the pulsation; and a pulsation width correcting unit adapted to correct the width of the pulsation on the basis of the temperature of the buffer unit.

In order to improve estimation accuracy of a purging amount, a fuel cell system comprises a supply valve that controls a supply of an anode gas into an anode system, a purge valve that discharges an off-gas from the anode system, a pressure detecting unit configured to estimate or measures a pressure inside the anode system, and a purging amount estimating unit configured to estimate a purging amount of the off-gas discharged from the anode system through the purge valve based on a pressure change inside the anode system during a purge valve close duration in a supply valve open state and a pressure change inside the anode system during a purge valve close duration in a supply valve close state.

A valve device for controlling an air flow of a fuel cell stack includes: a housing connected to the fuel cell stack and including a plurality of manifolds formed therein; a disk rotatably provided in the housing to control the air flow of the fuel cell stack; and a central shaft provided at the center of the housing to rotate the disk.

A system for controlling gas flow in a fuel cell circuit includes a fuel cell stack, a pressure sensor, and a valve to adjust a flow of gas through the fuel cell circuit. The system further includes an ECU designed to estimate pressure values of the gas at multiple locations in the fuel cell circuit based on the detected pressure of the gas and based on flow resistance values (including at the valve), the estimated pressure values including an estimated sensor pressure value at a location of the pressure sensor. The ECU is further designed to determine a pressure deviation between the detected pressure and the estimated sensor pressure value. The ECU is further designed to adjust the flow resistance value of the valve to determine a final flow resistance value of the valve that causes the pressure deviation to reach or drop below a threshold deviation amount.