Adjustable array of fuel cell systems

• US 20040009380A1
• Filed: 05/16/2003
• Published: 01/15/2004
• Est. Priority Date: 05/16/2002
• Status: Abandoned Application

• Current Assignee: Ballard Power Systems Corporation (Superior Plus Corporation)
• Original Assignee: Ballard Power Systems Corporation (Superior Plus Corporation)
• Inventors: Pearson, Martin T.
• Application Number:
  US10/440,034
• Publication Number:
  US 20040009380A1
• Time in Patent Office: Days
• US Class Current: 429/23
• CPC Class Codes: H01M 16/003 of fuel cells with other electrochemical devices, e.g. capacitors, electrolysers
• CPC Class Codes: H01M 8/04007 related to heat exchange
• CPC Class Codes: H01M 8/04089 of gaseous reactants
• CPC Class Codes: H01M 8/04753 of fuel cell reactants
• CPC Class Codes: H01M 8/0488 of fuel cell stacks
• CPC Class Codes: H01M 8/0491 of fuel cell stacks
• CPC Class Codes: H01M 8/04917 of auxiliary devices, e.g. batteries, capacitors
• 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 8/249 comprising two or more groupings of fuel cells, e.g. modular assemblies
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

An array of fuel cell systems are electrically couplable in series and/or parallel combinations to provide a variety of output powers, output current and/or output voltages. The fuel cell systems are “hot swappable” and redundant fuel cell systems may automatically replace faulty fuel cell systems to maintain output power, current and/or voltage, with or without switching. The configuration of fuel cell systems may be automatic and may be based on desired power, current and/or voltage, and/or based on the operating parameters of the fuel cell systems and/or power supply system.

Claims

1. A power supply system, comprising:

a power bus;

a first fuel cell system comprising a first fuel cell stack, a first electrical power storage device electrically coupled in parallel with the first fuel cell stack, a first series pass element electrically coupled in between the first fuel cell system and the first electrical power storage device, and a first regulating circuit controllingly coupled to the first series pass element;

a second fuel cell system comprising a second fuel cell stack, a second electrical power storage device electrically coupled in parallel with the second fuel cell stack, a second series pass element electrically coupled between the second fuel cell stack and the second electrical power storage device, and a second regulating circuit controlling coupled to the second series pass element;

a first switch selectively operable to electrically couple the first fuel cell system in series in the power bus; and

a second switch selectively operable to electrically couple the second fuel cell system in series in the power bus.

2. The power supply system of claim 1 wherein the first switch is one of a contactor and a transistor.

3. The power supply system of claim 1, further comprising:

a third fuel cell system; and

a third switch selectively operable to electrically couple the third fuel cell system in series in the power bus.

4. The power supply system of claim 1, further comprising:

a third fuel cell system; and

a third switch selectively operable to electrically couple the third fuel cell system in the power bus in parallel with at least one of the first and the second fuel cell systems.

5. The power supply system of claim 1 wherein the first switch is selectively operable according to an operating condition of the first fuel cell system, and further comprising:

a first redundancy switch electrically coupled in series with the first switch and selectively operable therewith to electrically couple the first fuel cell system in series to the power bus, the first redundancy switch being selectively operable according to an operating condition of at least the second fuel cell system.

6. The power supply system of claim 1 wherein the first switch is selectively operable according to an operating condition of the first fuel cell system, and further comprising:

a first redundancy switch electrically coupled in series with the first switch and selectively operable therewith to electrically couple the first fuel cell system in series to the power bus, the first redundancy switch being selectively operable according to a voltage across the power bus.

7. The power supply system of claim 1 wherein the first switch is selectively operable according to an operating condition of the first fuel cell system, and further comprising:

a first redundancy switch electrically coupled in series with the first switch and selectively operable therewith to electrically couple the first fuel cell system in series to the power bus, the first redundancy switch being selectively operable according to a desired output of the power supply system.

8. The power supply system of claim 1 wherein the first switch is selectively operable according to an operating condition of the first fuel cell system, and further comprising:

a first redundancy switch electrically coupled in series with the first switch and selectively operable therewith to electrically couple the first fuel cell system in series to the power bus, the first redundancy switch being selectively operable according to at least one of a desired nominal power output of the power supply system, a desired nominal voltage output of the power supply system, and a desired nominal current output of the power supply system.

9. A power supply system, comprising:

a power bus;

a first fuel cell system comprising a first fuel cell stack, a first electrical power storage device electrically coupled in parallel with the first fuel cell stack, a first reactant supply system having a first control element operable to control a partial pressure of at least a first reactant to the first fuel cell stack;

a second fuel cell system comprising a second fuel cell stack, a second electrical power storage device electrically coupled in parallel with the second fuel cell stack, a second reactant supply system having a second control element operable to control a partial pressure of at least a first reactant to the second fuel cell stack;

a first switch selectively operable to electrically couple the first fuel cell system in series in the power bus; and

a second switch selectively operable to electrically couple the second fuel cell system in series in the power bus.

10. A power supply system, comprising:

a power bus;

a plurality of fuel cell systems electrically couplable in series to the power bus, each of the fuel cell systems having a fuel cell stack and an electrical power storage device electrically coupled in parallel with the fuel cell stack;

a plurality of switches selectively operable to electrically decouple a respective one of the fuel cell systems from the power bus, each of the switches responsive to an operating condition of the respective one of the fuel cell systems; and

at least a first redundancy switch selectively operable to electrically couple a respective first one of the plurality of fuel cell systems to the power bus, the first redundancy switch responsive to an operating condition different from the operating condition of the respective first one of the plurality of fuel cells.

11. The power supply system of claim 10, further comprising:

an additional number of redundancy switches, each of the additional number of redundancy switches selectively operable to electrically couple a respective one of the fuel cell systems to the power bus in response to an operating condition different from the operating condition of the respective one of the fuel cells.

12. The power supply system of claim 10 wherein the operating condition that the first redundancy switch is responsive to is an operating condition of at least one of the fuel cell systems other than the respective first fuel cell system that the first redundancy switch is selectively operable to electrically couple to the power bus.

13. The power supply system of claim 10 wherein the operating condition that the first redundancy switch is responsive to is a voltage across an output of at least one of the fuel cell systems other than the respective first fuel cell system that the first redundancy switch is selectively operable to electrically couple to the power bus.

14. The power supply system of claim 10 wherein each of the fuel cell systems further comprise a number of sensors for determining a set of operating parameters of the respective fuel cell system and a processor configured to determine an operating condition of the respective fuel cell system based on the determined set of operating parameters, and wherein the operating condition that the first redundancy switch is responsive to is the operating condition determined by at least one of the processors.

15. The power supply system of claim 10 wherein the operating condition that the first redundancy switch is responsive to is at least one of a power output of the power bus, a voltage across the power bus and a current output of the power bus.

16. The power supply system of claim 10 wherein the operating condition that the first redundancy switch is responsive to is at least one of a desired nominal power output of the power supply system, a desired nominal voltage output of the power supply system, and a desired nominal current output of the power supply system.

17. The power supply system of claim 10, further comprising:

a controller communicatingly coupled to receive a set of operating parameters from each of the plurality of fuel cell systems, the controller configured to determine an operating condition of the fuel cell systems based on the received sets of operating parameters, and wherein the operating condition that the first redundancy switch is responsive to is the operating condition determined by the controller.

18. The power supply system of claim 10, further comprising:

a first diode electrically coupled in series in the power bus between the first and the second fuel cell systems.

19. The power supply system of claim 10 wherein the electrical power storage devices are at least one of a number of battery cells and a number of super-capacitors.

20. A power supply system, comprising:

a power bus;

at least two fuel cell systems; and

means for selectively electrically coupling the at least two fuel cell systems in series in the power bus, wherein each of the fuel cell systems comprises a fuel cell stack and an electrical power storage device electrically coupled in parallel with the fuel cell stack, the electrical power storage device comprising at least one of a battery and an ultracapacitor electrically coupled to a charging current limiter.

21. The power supply system of claim 20 wherein each of the fuel cell systems comprises a fuel cell stack and an electrical power storage device electrically coupled in parallel with the fuel cell stack, and means for controlling a flow of current from the fuel cell stack to the electrical power storage device and the power bus.

22. The power supply system of claim 20 wherein each of the fuel cell systems comprises a fuel cell stack and an electrical power storage device electrically coupled in parallel with the fuel cell stack, a series pass element electrically coupled between the fuel cell stack and the electrical power storage device, and regulating means for regulating a series pass element electrically coupled between the fuel cell stack and the electrical power storage device.

23. The power supply system of claim 20 wherein the means for selectively electrically coupling the at least two fuel cell systems in series comprises a respective switch for each of the fuel cell systems, each of the switches responsive to an operating condition of at least one of the other fuel cell systems.

24. The power supply system of claim 20 wherein the means for selectively electrically coupling the at least two fuel cell systems in series comprises a respective first switch and second switch for each of the fuel cell systems, each of the first switches responsive to an operating condition of at least one of the other fuel cell systems and each of the respective second switches responsive to an operating condition of the respective fuel cell system.

25. The power supply system of claim 20 wherein the means for selectively electrically coupling the at least two fuel cell systems in series comprises a controller responsive to a request for at least one of a desired power output, a desired current output and a desired voltage output of the power supply system.

26. A method of operating a power supply system having at least a first and a second fuel cell system, the method comprising:

electrically coupling a first fuel cell system in series to a power bus at a first time;

determining an existence of a fault condition;

in response to the fault condition, at a second time automatically electrically coupling a second fuel cell system to the power bus in series; and

automatically electrically decoupling the first fuel cell system from the power bus.

27. The method of claim 26 wherein determining an existence of a fault condition includes determining an operating condition of the first fuel cell system.

28. The method of claim 26 wherein determining an existence of a fault condition includes determining at least one of an output power, output voltage and output current of the first fuel cell system.

29. The method of claim 26 wherein determining an existence of a fault condition includes monitoring at least one of a battery current, a battery voltage, and a stack current in the first fuel cell system.

30. The method of claim 26 wherein determining an existence of a fault condition includes monitoring at least one of an ambient hydrogen level, an ambient oxygen level, and a reactant flow in the first fuel cell system.

31. The method of claim 26, further comprising:

electrically coupling a third fuel cell system to the power bus in series with the first fuel cell system at a third time, the third time being before the second time.

32. The method of claim 26, further comprising:

electrically coupling a third fuel cell system to the power bus in parallel with the first fuel cell system at a third time, the third time being before the second time.

33. The method of claim 26 wherein electrically coupling a first fuel cell system in series to a power bus at a first time includes closing a first switch electrically coupled between the fuel cell and the power bus and wherein electrically decoupling the first fuel cell system from the power bus includes opening a redundancy switch electrically coupled between the fuel cell and the power bus.

34. A method of operating a power supply system including a plurality of fuel cell systems, a first number of the fuel cell systems electrically coupled in series to a power bus and a second number of the fuel cell systems electrically couplable in series to the power bus, comprising:

determining an existence of a fault condition in at least one of the first number of fuel cell systems; and

automatically electrically coupling at least one of the second number of fuel cell systems to the power bus in series at a second time in response to the determination of the existence of the fault condition to maintain an electrical output on the power bus of the power supply system.

35. The method of claim 34, further comprising:

automatically electrically decoupling the at least one of the first number of fuel cell systems having the fault condition from the power bus.

36. The method of claim 34, further comprising:

for each of the fuel cell systems electrically coupled to the power bus, automatically regulating a flow of current from a fuel cell stack with respect to an electrical power storage device electrically coupled in parallel across the fuel cell stack by way of at least one of a respective series pass element and a respective regulating circuit and a reactant delivery system and a control element.

37. The method of claim 34, further comprising:

replacing the at least one of the fuel cell systems having the fault condition with a replacement fuel cell system.

38. The method of claim 34, further comprising:

replacing the at least one of the fuel cell systems having the fault condition with a replacement fuel cell system; and

electrically coupling the replacement fuel cell system in series to the power bus in response to the additional fault condition to maintain an electrical output on the power bus of the power supply system

39. The method of claim 34 wherein automatically electrically coupling at least one of the second number of fuel cell systems to the power bus in series at a second time in response to the determination of the existence of the fault condition to maintain an electrical output on the power bus of the power supply system includes activating a first transistor electrically coupled between the fuel cell and the power bus in proportion to a decrease associated with the fault condition in at least one of an output power, an output current, and an output voltage of the at least one of the first number of fuel cell systems.

40. A method of operating a power supply system having a plurality of fuel cell systems, at least a number of the fuel cell systems selectively couplable in series on a power bus, the method comprising:

determining an existence of a fault condition in at least one of the fuel cell systems electrically coupled in series on the power bus; and

automatically activating a linear control element electrically coupling a redundant one of the fuel cell systems in series to the power bus in response to the determined existence of the fault condition to maintain an electrical output on the power bus of the power supply system.

41. The method of claim 40, further comprising:

determining an existence of a fault condition in at least one of the fuel cell systems electrically coupled in series on the power bus; and

automatically activating a transistor electrically coupling a redundant one of the fuel cell systems in series to the power bus in response to the determined existence of the fault condition to maintain an electrical output on the power bus of the power supply system.