Electric power plant with adjustable array of fuel cell systems

• US 20040126635A1
• Filed: 05/16/2003
• Published: 07/01/2004
• Est. Priority Date: 05/16/2002
• Status: Active Grant

• Current Assignee: Ballard Power Systems Corporation (Superior Plus Corporation)
• Original Assignee: Ballard Power Systems Corporation (Superior Plus Corporation)
• Inventors: Pearson, Martin T.
• Granted Patent: US 7,087,327 B2
• 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 electric power plant includes an array of fuel cell systems. The 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.

Claims

1. An electric power plant comprising:

a power supply system, the power supply system comprising

a power bus,

a first and second fuel cell system, each fuel cell system comprising a fuel cell stack, 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,

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;

an oxidant supply system for supplying an oxidant gas to at least one of the fuel cell stacks; and

a fuel supply system for supplying a fuel gas to at least one of the fuel cell stacks.

2. The power plant of claim 1 wherein the first fuel cell system comprises a first fuel cell stack, a first electrical 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 stack and the first electrical storage device, and a first regulating circuit controllingly coupled to the first series pass element, and wherein the second fuel cell system comprises a second fuel cell stack, a second electrical 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 storage device, and a second regulating circuit controlling coupled to the second series pass element.

3. The power plant of claim 1 wherein the first fuel cell system comprises a first fuel cell stack, and 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, and wherein the second fuel cell system comprises a second fuel cell stack, and 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.

4. The power plant of claim 1 wherein the first switch is one of a contactor and a transistor.

5. The power plant of claim 1 wherein the power supply further comprises 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.

6. The power plant of claim 1 wherein the power supply system further comprises 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.

7. The power plant of claim 1 wherein the first switch is selectively operable according to an operating condition of the first fuel cell system, and wherein the power supply system further comprises 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 an operating condition of at least the second fuel cell system, a voltage across the power bus, a desired output of the power supply system and a desired nominal current output of the power supply system.

8. The power plant of claim 1 wherein the power supply system further comprises a first diode electrically coupled in series in the power bus between the first and the second fuel cell systems.

9. An electric power plant comprising:

an array of fuel cell systems, the array comprising,

a power bus,

a plurality of fuel cell systems electrically couplable in series to the power bus, each of the fuel cell systems comprising a fuel cell stack,

an electrical storage device electrically coupled in parallel with at least one of the fuel cell stacks,

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 in series 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;

an oxidant supply system for supplying an oxidant gas to at least one of the fuel cell stacks; and

a fuel supply system for supplying a fuel gas to at least one of the fuel cell stacks.

10. The power plant of claim 9 wherein the array further comprises 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 cell systems.

11. The power plant of claim 9 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.

12. The power plant of claim 9 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.

13. The power plant of claim 9 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.

14. The power plant of claim 9, 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.

15. The power plant of claim 9 wherein the electrical storage device is at least one of a battery and an ultracapacitor.

16. An electric power plant comprising:

at least two fuel cell systems, each of the fuel cell systems comprising

a fuel cell stack,

an electrical 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 storage device, and

regulating means for regulating a series pass element electrically coupled between the fuel cell stack and the electrical storage device;

means for selectively electrically coupling the at least two fuel cell systems in series;

an oxidant supply system for supplying an oxidant gas to at least one of the fuel cell stacks; and

a fuel supply system for supplying a fuel gas to at least one of the fuel cell stacks.

17. The power plant of claim 16 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.

18. An electric power plant comprising:

an array of fuel cell systems, each of the fuel cell systems comprising

a fuel cell stack,

an electrical storage device electrically coupled in parallel with the fuel cell stack,

a first series pass element electrically coupled between the fuel cell stack and the electrical storage device, and

first regulating means for regulating the first series pass element electrically coupled between the fuel cell stack and the electrical storage device;

an oxidant supply system for supplying an oxidant gas to at least one of the fuel cell stacks; and

,

a fuel supply system for supplying a fuel gas to at least one of the fuel cell stacks.

19. The power plant of claim 18 wherein the array comprises a power bus and a first arm, the first arm comprising a first plurality of the fuel cell systems electrically couplable to the power bus and electrically couplable in series to each other.

20. The power plant of claim 19 wherein the first arm of the array includes at least one redundant fuel cell system.

21. The power plant of claim 19 wherein the array further comprises a second arm comprising a second plurality of the fuel cell systems, wherein the second plurality of the fuel cell systems is electrically couplable to the power bus and electrically couplable in series to each other;

and the second arm is electrically couplable in parallel to the first arm.

22. The power plant of claim 21 wherein at least one of the first and second arms of the array includes at least one redundant fuel cell system.

23. The power plant of claim 18 wherein the electrical storage device comprises a storage battery or an ultracapacitor.

24. The power plant of claim 18 wherein the fuel supply system comprises hydrogen storage equipment.

25. The power plant of claim 18 wherein the fuel supply system comprises pressurized hydrogen tanks.

26. The power plant of claim 18, further comprising a rectifier electrically couplable to the electrical storage device and an AC power source.

27. The power plant of claim 18, further comprising an inverter electrically couplable to the array.

28. An electric power plant comprising:

a power supply system, the power supply system comprising

a power bus,

a first and second fuel cell system,

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;

an oxidant supply system for supplying an oxidant gas to at least one of the fuel cell stacks;

a fuel supply system for supplying a fuel gas to at least one of the fuel cell stacks; 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.