Claims
- 1. In a method for identifying a gas leak between anode and cathode gas areas of a PEM fuel cell by detecting a cell voltage, the improvement which comprises:
- purging the anode and cathode gas areas with nitrogen in a first time period;
- filling the cathode gas area with oxygen and the anode gas area with hydrogen in a second time period; and
- then measuring and evaluating the cell voltage as a function of time.
- 2. The method according to claim 1, which comprises keeping at least one of the anode and cathode gas areas closed during the measuring step.
- 3. The method according to claim 1, which comprises removing the nitrogen from the anode and cathode gas areas between the first and second time periods.
- 4. The method according to claim 1, which comprises carrying out the step of filling the cathode gas area with oxygen during the second time period, for about 1 s at an absolute pressure of about 2.3 bar.
- 5. The method according to claim 1, which comprises removing a majority of the oxygen after the second time period.
- 6. The method according to claim 1, which comprises monitoring the cell voltage to about half of a no-load voltage of the PEM fuel cell.
- 7. The method according to claim 1, which comprises monitoring the cell voltage to about 0.5 V.
- 8. The method according to claim 1, which comprises carrying out the step of measuring the cell voltage for 15 to 20 s.
- 9. The method according to claim 1, which comprises carrying out the step of measuring the cell voltage for about 16 s.
- 10. The method according to claim 1, which comprises carrying out the step of filling the anode gas area with hydrogen during the second time period, for about 0.1 s at an absolute pressure of about 2.0 bar.
- 11. A fuel cell system, comprising:
- a PEM fuel cell having anode and cathode gas areas;
- first connections for supplying nitrogen, oxygen and hydrogen to and removing nitrogen, oxygen and hydrogen from said PEM fuel cell;
- a second connection for tapping off electrical voltage from said PEM fuel cell; and
- a controller connected to said first connections and programmed to:
- purge the anode and cathode gas areas with nitrogen in a first time period;
- fill the cathode gas area with oxygen and the anode gas area with hydrogen in a second time period; and
- subsequently measure and evaluate the cell voltage as a function of time.
Priority Claims (1)
Number |
Date |
Country |
Kind |
196 49 436 |
Nov 1996 |
DEX |
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CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation of copending International Application Ser. No. PCT/DE97/02695, filed Nov. 17, 1997, which designated the United States.
US Referenced Citations (5)
Foreign Referenced Citations (2)
Number |
Date |
Country |
0716463A2 |
Jun 1996 |
EPX |
55-154075 |
Dec 1980 |
JPX |
Continuations (1)
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Number |
Date |
Country |
Parent |
PCTDE9702695 |
Nov 1997 |
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