Siemens Aktiengesellschaft

Siemens Aktiengesell Schaft

Walter Stühler

Arno Mattejat

Joachim Hoffmann

Albert Hammerschmidt

Detlev Coerlin

Willi Bette

Christoph Nölscher

Josef Lersch

Armin Datz

Torsten Brandt

Ottmar Voitlein

Herbert Stenger

Igor Mehltretter

Reinhard Muller

Dieter Illner

Silke Latzel

Martin Keim

Michael Braunecker

Franco Tardivo

Torsten Lochner

Frank BÄRNREUTHER

Stefan Karbacher

Thomas Mahnke

Mechanical stresses of the membrane of a fuel cell can be reduced by virtue of the fact that the supply of feed gas to a gas chamber of the fuel cell takes places, initially, by means of a first pressure increasing speed and then by means of a second pressure increasing speed. The first pressure increasing speed is slower than the second pressure increasing speed. Pressure surges are prevented in the membrane due to the lower pressure increasing speed in the first phase of the gas supply, and as a result, the life span of the membrane is increased.

Method for supplying fuel gas to a gas chamber of a fuel cell and fuel cell

During the operation of a fuel-cell assembly, the latter is supplied with ambient air with the aid of a liquid ring pump. Any foreign matter that is contained in the air is taken up by the service fluid of the liquid ring pump. The charging of the service fluid with foreign matter is controlled. In particular, the service fluid is continuously conducted in an circuit via a purification device.

Method for operating a fuel cell system and fuel cell system

A process for operating a PEM fuel cell unit containing at least one PEM fuel cell block and a speed-controlled compressor connected upstream. To control changing an electrical current I of the PEM fuel cell block to a new reference value I.sub.SN, a speed n of the compressor is set in a first step to a maximum value n.sub.M and in a second step is reduced to a speed n.sub.SN corresponding to the new reference value I.sub.SN. By this expedient improved dynamics for brief and rapid load changes are achieved.

Process for operation of a PEM fuel cell unit

A process for operating a fuel cell installation and a fuel cell installation for carrying out the process include at least one fuel cell block. A process gas for the fuel cell block is fed into the fuel cell block with a liquid ring compressor. In this way, the process gas is humidified at the same time as it is compressed, thus using the compression heat simultaneously as evaporation enthalpy, as well as the heat from the cooling circuit of the fuel cell stack.

Process for operating a fuel cell installation and fuel cell

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Hirschaid, Germany

Walter Stühler