| US 7,531,253 B2 | ||
| Method for monitoring the operational state of a fuel cell stack | ||
| Erich Ramschak, Vasoldsberg (Austria) | ||
| Assigned to AVL List GmbH, Graz (Austria) | ||
| Filed on Oct. 04, 2005, as Appl. No. 11/242,121. | ||
| Claims priority of application No. 1678/2004 (AT), filed on Oct. 07, 2004. | ||
| Prior Publication US 2006/0078788 A1, Apr. 13, 2006 | ||
| Int. Cl. H01M 8/04 (2006.01) | ||
| U.S. Cl. 429—13 [429/23] | 20 Claims |
| 1. A method for monitoring the operational state of a fuel cell stack comprising a plurality of individual cells connected
in series, comprising the steps of:
impressing a low-frequency current or voltage signal on the fuel cell stack,
measuring the resulting current or voltage signal, and
inferring the operational state of individual cells of the fuel cell stack from at least one change in the harmonic content
of said current or voltage signal.
|