Fuel cell flooding detection

• US 20050175872A1
• Filed: 02/09/2004
• Published: 08/11/2005
• Est. Priority Date: 02/09/2004
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Trabold, Thomas A., Falta, Steven R.
• Granted Patent: US 7,781,118 B2
• Time in Patent Office: Days
• US Class Current: 429/413
• CPC Class Codes: H01M 8/04104 Regulation of differential pressures
• CPC Class Codes: H01M 8/04126 Humidifying
• CPC Class Codes: H01M 8/04291 Arrangements for managing water in solid electrolyte fuel cell systems H01M8/04119 takes precedence
• CPC Class Codes: H01M 8/04432 Pressure differences, e.g. between anode and cathode
• CPC Class Codes: H01M 8/04753 of fuel cell reactants
• CPC Class Codes: H01M 8/04835 of fuel cell reactants
• CPC Class Codes: H01M 8/04992 characterised by the implementation of mathematical or computational algorithms, e.g. feedback control loops, fuzzy logic, neural networks or artificial intelligence
• CPC Class Codes: H01M 8/0612 from carbon-containing material
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

A pressure fluctuation parameter (for example, a statistical indicator such as a root-mean-square value) from a set of differential pressure measurements between the inlet and the outlet of a fuel cell reactant flow channel carrying vaporized water is used to define flooding onset. Vaporized water in the flow of gas (air) through the flow channels is controlled in response to the parameter. Benefits include efficient operation (i.e., minimized stoichiometry) and effective management of rapid power transients in a fuel cell.

Claims

1. A fuel cell stack comprising:

a fuel cell having an inlet, a flow field in fluid communication with said inlet and an outlet in fluid communication with said flow field;

a vaporized water source in fluid communication with said inlet;

a differential pressure transducer repeatedly measuring a differential pressure across said flow field and generating a set of differential pressure signals; and

a controller in communication with said differential pressure transducer, said controller having executable logic for determining a differential pressure fluctuation parameter from said set of differential pressure signals and control circuitry for controlling said vaporized water source in response to said differential pressure fluctuation parameter.

2. The fuel cell of claim 1 wherein said executable logic further comprises executable logic for determining a differential pressure fluctuation parameter as a representative statistical value from said set of differential pressure signals.

3. The fuel cell of claim 2 wherein said representative statistical value is a root-mean-square value.

4. The fuel cell of claim 2 wherein said controller further comprises executable logic for comparing said representative statistical value to a threshold variable.

5. The fuel cell of claim 4 wherein said representative statistical valve is a root-mean-square value.

6. The fuel cell of claim 1 wherein said executable logic further comprises executable logic for determining fluctuation instances in said set of differential pressure signals, a maximum value for each fluctuation instance, a minimum value for each fluctuation instance, and a representative statistical value from said maximum values and said minimum values.

7. The fuel cell of claim 6 wherein said representative statistical value is a root-mean-square value.

8. The fuel cell of claim 6 wherein said executable logic further comprises executable logic for comparing said representative statistical value to a threshold variable.

9. The fuel cell of claim 8 wherein said representative statistical value is a root-mean-square value.

10. A method for operating a fuel cell comprising:

mixing vaporized water with a gaseous reactant;

introducing said fluid into a reactant flow field of a fuel cell;

measuring a set of differential pressures across said reactant flow field;

determining a differential pressure fluctuation parameter from said set of differential pressures; and

controlling said vaporized water in response to said differential pressure fluctuation parameter.

11. The method of claim 10 wherein determining a differential pressure fluctuation parameter comprises:

identifying fluctuation instances in said set of differential pressures;

determining a maximum value for each fluctuation instance;

determining a minimum value for each fluctuation instance; and

computing a representative statistical value from said maximum values and said minimum values.

12. The method of claim 11 further comprising comparing a threshold variable to said representative statistical value.

13. The method of claim 12 further comprising controlling said vaporized water in said two-phase fluid in response to said comparison.

14. The method of claim 11 wherein said representative statistical value is computed as a root-mean-square value.

15. The method of claim 10 wherein determining a differential pressure fluctuation parameter defines a representative statistical value from said set differential pressures.

16. The method of claim 15 wherein said representative statistical value is computed as a root-mean-square value.