Fuji Electric Co., Ltd.

Hiroyuki Tajima

Toshio Hirota

Tomohiro Sugiyama

Tetsuo Arai

In order to control a fuel cell having a fuel cell stack to which reformed fuel and oxidizing agent are supplied, an output current from the fuel cell is detected while the voltage of the fuel cell is maintained at a constant voltage and the amount of the fuel and/or the oxidizing agent is controlled in accordance with the detected output current to stably generate electric power. At least one of a plurality of unit cells constituting the fuel cell stack is used as a monitoring cell having a current-voltage characteristic curve which is lower than that of the other unit cells, and an output current from the monitoring cell is detected while the voltage of this cell is maintained at a constant voltage, and the supplied amount of the fuel and/or the oxidizing agent is controlled in accordance with the detected current value to stably generate electric power output.

Method for controlling a fuel cell

A fuel cell system is disclosed including a fuel cell having a fuel supply subsystem including a fuel chamber and an air or oxygen supply subsystem including an air or oxygen chamber, a burner, in which fuel derived from the fuel subsystem of the fuel cell is burned with air or oxygen, and a storage tank, in which combustion gas produced in the burner is stored as replacement gas so that the replacement gas is fed from the storage tank into the fuel subsystem of the fuel cell at the time of start and stop of operation of the fuel cell.

Fuel cell system

A fuel cell system for replacement of fuel gas includes a fuel cell having a fuel chamber, a fuel supply subsystem communicating with the fuel chamber of the fuel cell and a contact-type burner installed in the fuel supply subsystem for burning, with air, fuel derived from the fuel supply subsystem. At the time of start of operation of the fuel cell, in the operating state of the burner, a feed quantity of the fuel gas to be introduced into the burner is gradually increased while a feed quantity of the air to be introduced into the burner is decreased from 100% to 0% so that the air in the fuel chamber is replaced with the fuel gas. At the time of stop of operation of the fuel cell, in the operating state of the burner, the feed quantity of the fuel gas to be introduced into the burner is gradually decreased while the feed quantity of the air to be introduced into the burner is increased from 0% to 100% so that the fuel gas in the fuel chamber is replaced with the air.

Fuel cell system for replacement of fuel gas

The present invention relates to a fuel cell having separate plates acting as bipolar plates which are sandwiched between the two adjacent cell elements. A cell stack of a fuel cell is formed therein with tunnel-shaped cooling gas passages extending between and open at two opposite sides thereof. Reactive gas supply passages for fuel gases and air are isolated from the cooling gas passages and extend between and open at the two opposite sides thereof which are different from those of the cooling gas passages. Therefore, the separate plates have their reactive gas supply passages supplied through manifolds, which are arranged at the sides of the fuel cell in a manner to face the entrance and exit ports of the reactive gas supply passages. The reactive gases are supplied at rates sufficient to be consumed by the galvanic reaction. The cooling gas passages are supplied through manifolds, which are arranged at the other sides of the fuel cell, i.e. different from the sides of the reactive gas supply passages. The cooling gases take no part in the galvanic reaction at a proper flow rate, whereby the respective cell elements constructing the cell stack of the fuel cell is cooled uniformly without establishing a temperature difference between the cell elements.

Fuel cell

By utilizing in a multi-layered fuel cell, plastic separators with the inter-cell connectors supported in resilient but vaportight fashion within the separators, a lighweight fuel cell may be realized which does not suffer from fuel-oxidizer leakage despite temperature rises and accompanying differential component expansion.

Growing community of inventors

Kawasaki, Japan

Hiroyuki Tajima