Daimler Ag

Ballard Power Systems Ag

Nucellsys Gmbh

Hans-Frieder Walz

Martin Schuessler

Stefan Boneberg

Joerg Schuetz

Monika Derflinger

Volker Schempp

Isabel Haas

The invention relates to a method for operating a fuel cell system in a mode of reduced power output. The fuel cell system comprises a fuel cell stack (BS) having at least one fuel cell (BZ) with an anode (A), a cathode (K), and a proton exchange membrane, anode and cathode inlets, anode and cathode outlets, and a hydrogen and air supply. In order not to adversely affect the life span of the fuel cell system, the air supply to the cathode (K) is interrupted during the changeover to the mode of reduced power output, and an electric voltage (U) of the fuel cell stack (BS) is reduced by means of a current pulse.

Method for operating a fuel cell system in a mode of reduced power output

A method for operating a gas generation device, for example, for a fuel cell system, having at least two gas generation units through which a starting-material stream flows in series. The two gas generating units have a first and second rated power P, Pand a first and second predetermined operating temperature T, T, and the first gas generation unit has a lower thermal mass than the second gas generation unit. During a starting phase only the first gas generation unit is operated, with a power P&#x3e;P. After the end of the starting phase at least the second gas generation unit is operated.

Method for operating a gas generation device in a fuel cell system

A system is used for cooling a fuel cell arrangement, particularly a fuel cell arrangement with a gas generating system in a motor vehicle. A coolant circuit for the system is connected to a cooler, a coolant delivery device, a fuel cell and at least another component to be cooled. The coolant circuit has at least two valve devices which are each assigned to the fuel cell and the at least another component to be cooled. By means of the valve devices, a flow rate of the coolant through the fuel cell or the another component to be cooled can be influenced as a function of the temperature in the region associated with the fuel cell or the another component.

System and method for cooling a fuel cell arrangement

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Bad Ueberkingen, Germany

Hans-Frieder Walz