Fuel cell assembly and method of control

Patent metadata

Field	Value
Publication number	US-9318759-B2
Application number	US-201114363567-A
Country	US
Kind code	B2
Filing date	Dec 9, 2011
Priority date	Dec 9, 2011
Publication date	Apr 19, 2016
Grant date	Apr 19, 2016

Abstract

An exemplary method includes of operating a fuel cell at a first power output level that includes a plurality of operation parameters. Each operation parameter has a value to satisfy a first power demand. A change between the first power demand and a second power demand is determined. At least a first one of the operation parameters is maintained at a value corresponding to the first power output level or at an intermediate value while at least a second one of the operation parameters is changed to a value corresponding to a second power output level to satisfy the second power demand. The first operation parameter is delayed from changing to a value corresponding to the second power output level until a predetermined criterion is met.

First claim

We claim:

1. A method of operating a fuel cell, comprising:
operating a fuel cell at a first power output level that includes a plurality of operation parameters, each operation parameter having a value corresponding to the first power output level to satisfy a first power demand;
determining a change between the first power demand and a second power demand;
maintaining at least a first one of the operation parameters at the value corresponding to the first power output level while changing at least a second one of the operation parameters to a value corresponding to a second power output level to satisfy the second power demand;
delaying changing the first operation parameter to a value corresponding to the second power output level until a predetermined criterion is met;
clipping a cell stack assembly voltage; and
selecting a voltage value for the clipping based on temperature.

2. The method of claim 1 , wherein the first power demand is greater than the second power demand.

3. The method of claim 2 , wherein changing the second operation parameter comprises reducing fuel cell pressure.

4. The method of claim 2 , wherein the first operation parameter includes at least one of reactant flow, humidity, or cell stack assembly voltage.

5. The method of claim 2 , comprising changing the first operation parameter to a value corresponding to an intermediate power output level between the first and second power output levels.

6. The method of claim 1 , wherein the first power demand is less than the second power demand.

7. The method of claim 6 , wherein the first operation parameter is pressure.

8. The method of claim 1 , wherein the predetermined criterion includes at least one of time and temperature of the fuel cell.

9. The method of claim 1 , wherein maintaining at least a first one of the operation parameters at the value corresponding to the first power output level while changing at least a second one of the operation parameters to a value corresponding to a second power output level to satisfy the second power demand comprises directing excess power to a power sink when the first demand is greater than the second demand.

10. The method of claim 1 , wherein the second operation parameter includes at least one of reactant flow, humidity, or cell stack assembly voltage.

11. The method of claim 1 , comprising decreasing the voltage value for the clipping as the temperature increases.

12. A fuel cell assembly comprising:
a cell stack assembly; and
a controller configured to:
operate the cell stack assembly at a first power output level that includes a plurality of operation parameters, each operation parameter having a value corresponding to a first power demand;
determine a change between the first power demand and a second power demand;
maintain at least a first one of the operation parameters at a value corresponding to the first power output level while changing at least a second one of the operation parameters to a value corresponding to a second power output level;
delay a change in the first operation parameter to a value corresponding to the second power output level until a predetermined criterion is met;
clip a cell stack assembly voltage; and
select a clip voltage value based on temperature.

13. The fuel cell assembly of claim 12 , wherein the first power demand is greater than the second power demand.

14. The fuel cell assembly of claim 13 , wherein changing the second operation parameter comprises reducing a pressure of the cell stack assembly.

15. The fuel cell assembly of claim 13 , wherein the first operation parameter includes at least one of reactant flow, humidity, or cell stack assembly voltage.

16. The fuel cell assembly of claim 13 , wherein changing the first operation parameter to a value corresponding to an intermediate power output level between the first and second power output levels.

17. The fuel cell assembly of claim 12 , wherein the first power demand is less than the second power demand.

18. The fuel cell assembly of claim 17 , wherein the first operation parameter comprises pressure.

19. The fuel cell assembly of claim 12 , wherein the second operation parameter includes at least one of reactant flow, humidity, or cell stack assembly voltage.

20. The fuel cell assembly of claim 12 , wherein the predetermined criterion includes at least one of time and temperature of the cell stack assembly.

21. The fuel cell assembly of claim 12 , wherein the controller is configured to direct excess power to a power sink when the first power demand is greater than the second power demand.

22. The fuel cell assembly of claim 21 , wherein the power sink includes at least one of a battery, a capacitor, or a resistor.

23. The fuel cell assembly of claim 12 , wherein the controller is configured to decrease the clip voltage value as the temperature increases.

Assignees

• O'Neill Jonathan
• Patterson Timothy W
• Audi Ag

Inventors

• O'Neill Jonathan
• Patterson Timothy W

Classifications

• H01M8/04753

  of fuel cell reactants · CPC title

• H01M8/0438

  Pressure; Ambient pressure; Flow · CPC title

• H01M8/0488

  of fuel cell stacks · CPC title

• H01M8/04529

  of the electrolyte · CPC title

• H01M16/003

  of fuel cells with other electrochemical devices, e.g. capacitors, electrolysers · CPC title