Fuel cell system controller

• US 6,495,277 B1
• Filed: 07/26/2000
• Issued: 12/17/2002
• Est. Priority Date: 07/27/1999
• Status: Expired due to Term

• Current Assignee: DCNS SA (Government of France)
• Original Assignee: IdaTech LLC (IdaTech Ltd.)
• Inventors: Holmes, Craig F., Herron, Thomas G., Edlund, David J.
• Primary Examiner(s): Kalafut, Stephen
• Assistant Examiner(s): Alejandro, Raymond
• Application Number:
  US09/626,311
• Time in Patent Office: 874 Days
• Field of Search: 429/22, 429/33, 429/24, 429/25, 429/17, 429/13, 429/26, 320/101, 340/636
• US Class Current: 429/411
• CPC Class Codes: H01M 16/006 of fuel cells with rechargeable batteries
• CPC Class Codes: H01M 2250/405 Cogeneration of heat or hot water
• CPC Class Codes: H01M 8/04037 Electrical heating
• CPC Class Codes: H01M 8/04089 of gaseous reactants
• CPC Class Codes: H01M 8/04298 Processes for controlling fuel cells or fuel cell systems
• CPC Class Codes: H01M 8/04388 of anode reactants at the inlet or inside the fuel cell
• CPC Class Codes: H01M 8/04425 at auxiliary devices, e.g. reformers, compressors, burners
• CPC Class Codes: H01M 8/04619 of fuel cell stacks
• CPC Class Codes: H01M 8/04626 of auxiliary devices, e.g. batteries, capacitors
• CPC Class Codes: H01M 8/04664 Failure or abnormal function
• CPC Class Codes: H01M 8/04776 at auxiliary devices, e.g. reformer, compressor, burner
• CPC Class Codes: H01M 8/04798 of fuel cell reactants
• CPC Class Codes: H01M 8/0494 of fuel cell stacks
• CPC Class Codes: H01M 8/04947 of auxiliary devices, e.g. batteries, capacitors
• CPC Class Codes: H01M 8/04955 Shut-off or shut-down of fuel cells
• 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: H01M 8/0656 by electrochemical means H01M8/065 takes precedence
• CPC Class Codes: H01M 8/0687 Reactant purification by the use of membranes or filters
• CPC Class Codes: H01M 8/249 comprising two or more groupings of fuel cells, e.g. modular assemblies
• CPC Class Codes: Y02B 90/10 : Applications of fuel cells in buildings
• CPC Class Codes: Y02E 60/10 : Energy storage using batteries
• CPC Class Codes: Y02E 60/50 : Fuel cells

Abstract

A fuel cell system that includes a control system for regulating the power produced by the fuel cell system. The fuel cell system includes a fuel cell stack adapted to produce electrical power from a feed. In some embodiments, the fuel cell system includes a fuel processing assembly adapted to produce the feed for the fuel cell stack from one or more feedstocks. The control system regulates the power produced by the fuel cell system to prevent damage to, and/or failure of, the system.

Claims

1. A fuel cell system, comprising:

a fuel processing assembly adapted to produce a feed stream from one or more feedstocks;

a fuel cell stack including at least one fuel cell, wherein the fuel cell stack is adapted to receive the feed stream from the fuel processing assembly and to produce electrical power therefrom;

a battery bank adapted to store electrical power, wherein the battery bank has a current level of stored power; and

a control system adapted to regulate the rate power is produced by the fuel cell stack responsive to at least one selected variable, wherein the control system is configured to restrict the fuel cell stack from having greater than its rated power output drawn therefrom; and

further wherein the at least one selected variable includes the current level of stored power of the battery bank.

2. The system of claim 1, wherein the fuel processing assembly has a maximum production rate of the feed stream, and further wherein the at least one selected variable includes the maximum production rate of the feed stream.

3. The system of claim 1, wherein the fuel processing assembly has a currently available production rate of the feed stream, and further wherein the at least one selected variable includes the currently available production rate of the feed stream.

4. The system of claim 1, wherein the fuel cell stack has a maximum rated power output, and further wherein the at least one selected variable includes the maximum rated power output of the fuel cell stack.

5. The system of claim 1, wherein the fuel cell stack has a currently available power output, and further wherein the at least one selected variable includes the currently available power output of the fuel cell stack.

6. The system of claim 1, wherein the battery bank has a maximum stored charge, and further wherein the at least one selected variable includes the maximum stored charge of the battery bank.

7. The system of claim 1, wherein the control system includes at least one threshold value for each of the at least one selected variables.

8. The system of claim 7, wherein the control system is adapted to regulate the rate power is produced by the fuel cell system if one or more of the selected variables exceed the corresponding at least one threshold value.

9. The system of claim 1, wherein the control system is adapted to regulate the rate of power production by the fuel cell system by limiting the currently available power output of the fuel cell stack.

10. The system of claim 1, wherein the control system is adapted to regulate the rate of power production by the fuel cell system by adjusting the currently available production rate of the feed stream.

11. The system of claim 1, wherein the system is in communication with one or more facilities adapted to load the system to draw power therefrom.

12. The system of claim 11, wherein the at least one selected variable includes the load on the system from the one or more facilities.

13. The system of claim 11, wherein the load includes a thermal load.

14. The system of claim 13, wherein the control system is adapted to regulate the fuel cell system to meet the thermal load.

15. The system of claim 11, wherein responsive to the load from the one or more facilities, the fuel cell system provides power to the facility from the fuel cell stack, and further wherein the control system is adapted to limit the power provided by the fuel cell system to prevent the power provided from exceeding a maximum rated power output of the fuel cell stack or a currently available power output of the fuel cell stack.

16. The system of claim 1, wherein the battery bank includes a charge of stored power, and further wherein the control system is adapted to regulate the fuel cell system to produce power for increasing the charge of stored power when the charge of stored power falls below a selected threshold.

17. The system of claim 1, wherein the feed stream includes hydrogen gas.

18. The system of claim 17, wherein the fuel processing assembly includes at least one fuel processor adapted to produce the feed stream by electrolysis of water.

19. The system of claim 17, wherein the fuel processing assembly includes at least one fuel processor adapted to produce the feed stream by steam reforming at least one of a hydrocarbon and an alcohol.

20. The system of claim 19, wherein the fuel processing assembly is adapted to produce a mixed gas stream from the one or more feedstocks, and further wherein the fuel processing assembly includes a purification region in which the mixed gas stream is separated into the feed stream and at least one byproduct stream.

21. The system of claim 20, wherein the purification region includes a membrane module including at least one hydrogen selective membrane.

22. The system of claim 1, wherein the at least one selected variable further includes a load being applied to the system.

23. The system of claim 22, wherein the system is in communication with one or more facilities adapted to apply at least a portion of the load to the system.

24. The system of claim 22, wherein the feed stream includes hydrogen gas and the fuel processing assembly includes a steam reformer.

25. The system of claim 16, wherein the at least one selected variable further includes a load being applied to the system.

26. The system of claim 25, wherein the system is in communication with one or more facilities adapted to apply at least a portion of the load to the system.

27. The system of claim 26, wherein the feed stream includes hydrogen gas and the fuel processing assembly includes a steam reformer.

28. The fuel cell system of claim 1, wherein the fuel cell stack includes a currently available power output and the control system is further adapted to regulate the power produced by the fuel cell stack to prevent the power output from exceeding the currently available power output of the fuel cell stack.

30. The system of claim 27, wherein the control system is further adapted to prevent the power output from exceeding a selected percentage of at least one of the maximum rated power output of the fuel cell stack or the currently available power output of the fuel cell stack.

29. A fuel cell system, comprising:

a fuel cell stack including at least one fuel cell adapted to produce electrical power from a feed, wherein the fuel cell stack has a maximum rated power output and a currently available power output;

a battery bank having a currently available charge of stored power; and

a control system adapted to regulate the power produced by the fuel cell stack to prevent the power output from exceeding at least one of the maximum rated power output of the fuel cell stack and the currently available power output of the fuel cell stack, wherein the control system is adapted to regulate the fuel cell system at least in part responsive to the currently available charge of stored power of the battery bank.

31. The system of claim 29, further including a fuel processing assembly adapted to produce the feed from at least one feedstock.

32. The system of claim 31, wherein the fuel processing assembly includes a currently available rate of producing the feed and a maximum rate of producing the feed.

33. The system of claim 32, wherein the control system is adapted to regulate the fuel cell system responsive at least in part to the currently available rate of producing the feed.

34. The system of claim 32, wherein the control system is adapted to regulate the fuel cell system responsive at least in part to the maximum rate of producing the feed.

35. The system of claim 31, wherein the feed includes hydrogen gas.

36. The system of claim 29, wherein the control system is adapted to regulate the fuel cell system responsive at least in part to a load applied to the fuel cell system.

37. The system of claim 36, wherein the load includes a demand for electrical power.

38. The system of claim 36, wherein the load includes a demand for heat.

39. The system of claim 29, wherein the control system is further adapted to regulate the fuel cell system responsive at least in part to a load being applied to the fuel cell system.

40. The system of claim 39, wherein the system is in communication with one or more facilities adapted to apply at least a portion of the load to the system.

41. The system of claim 40, wherein the feed includes a stream of at least substantially pure hydrogen gas, and further wherein the system includes a source of hydrogen gas from which the feed is delivered to the fuel cell stack.

42. The system of claim 41, wherein the source of hydrogen gas includes a steam reforming region in which a stream containing hydrogen gas is formed from a carbon-containing feedstock and water, and further wherein the stream containing hydrogen gas forms at least a portion of the feed.

43. The fuel cell system of claim 29, wherein the control system is adapted to regulate the power produced by the fuel cell stack to prevent the power output from exceeding the maximum rated power output of the fuel cell stack.

44. The fuel cell system of claim 29, wherein the control system is adapted to regulate the power produced by the fuel cell stack to prevent the power output from exceeding the currently available power output of the fuel cell stack.

45. The fuel cell system of claim 29, wherein the control system is adapted to regulate the power produced by the fuel cell stack to prevent the power output from exceeding the maximum rated power output of the fuel cell stack and the currently available power output of the fuel cell stack.

46. The system of claim 29, further including means for producing the feed.

47. The system of claim 29, further including means for producing heat responsive to a demand for thermal energy.