Systems and methods for independently controlling the operation of fuel cell stacks and fuel cell systems incorporating the same

• US 8,617,754 B2
• Filed: 12/09/2011
• Issued: 12/31/2013
• Est. Priority Date: 06/12/2009
• Status: Active Grant

• Current Assignee: DCNS SA (Government of France)
• Original Assignee: DCNS SA (Government of France)
• Inventors: Edmiston, Thane Rea, Greenough, Benjamin Charles
• Primary Examiner(s): Cano, Milton I
• Assistant Examiner(s): THOMAS, BRENT C
• Application Number:
  US13/316,245
• Publication Number:
  US 20120088171A1
• Time in Patent Office: 753 Days
• Field of Search: 429/429, 429/428
• US Class Current: 429/429
• CPC Class Codes: H01M 8/04559 of fuel cell stacks
• CPC Class Codes: H01M 8/04619 of fuel cell stacks
• CPC Class Codes: H01M 8/0488 of fuel cell stacks
• CPC Class Codes: H01M 8/0494 of fuel cell stacks
• CPC Class Codes: Y02E 60/50 Fuel cells
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

The present disclosure is directed to systems and methods for independently controlling the operation of fuel cell stacks and to fuel cell systems incorporating the same. These systems and methods may include providing a fuel cell system including a plurality of fuel cell stacks and at least a first energy storage device and controlling the operation of the plurality of fuel cell stacks based at least in part on a variable associated with the fuel cell system and/or an energy consuming device. These systems and methods may further include beginning production of electrical output from the fuel cell system responsive to a start condition, initiating production of electrical output from the plurality of fuel cell stacks responsive to a plurality of stack start conditions, and ceasing the production of electrical output from the fuel cell stacks responsive to at least a first stack stop condition.

Claims

1. A method of operating a fuel cell system that includes an oxidant source configured to provide an oxidant stream, a fuel source configured to provide a fuel stream, and a plurality of fuel cell stacks, wherein the plurality of fuel cell stacks are configured to receive the fuel stream and the oxidant stream and to produce a stack electrical output therefrom, wherein the fuel cell system is configured to produce a system electrical output to supply to an energy consuming device, the method comprising:

beginning production of the system electrical output from the fuel cell system responsive to a system start condition, wherein the fuel cell system is in electrical communication with an energy storage device that is configured to store electrical energy and provide an energy storage device electrical output, and further wherein beginning production of the electrical output includes supplying the electrical output from the energy storage device;

initiating production of electrical output from a first fuel cell stack of the plurality of fuel cell stacks responsive to a first stack start condition, wherein the first stack start condition corresponds to the energy storage device reaching a first level of charge for a first stack start time; and

initiating production of electrical output from a second fuel cell stack of the plurality of fuel cell stacks responsive to a second stack start condition that is different from the first stack start condition, wherein the second stack start condition corresponds to the energy storage device reaching a second level of charge for a second stack start time, and further wherein the first level of charge is greater than the second level of charge.

2. The method of claim 1, wherein the fuel cell system is configured to satisfy an electrical load applied by the energy consuming device when a primary power system is unavailable to satisfy the load, and further wherein the system start condition includes detecting a change in the electrical output of the primary power system.

3. The method of claim 2, wherein the change in the electrical output of the primary power system includes at least one of a decrease in the electrical output from the primary power system, a decrease in the stability of the electrical output from the primary power system, and a lack of electrical output from the primary power system.

4. The method of claim 2, wherein at least one of the system start condition, the first stack start condition, and the second stack start condition includes detecting that the primary power system is at least temporarily unable to satisfy the electrical load applied by the energy consuming device.

5. The method of claim 4, wherein detecting that the primary power system is unable to satisfy the electrical load applied by the energy consuming device includes detecting that the energy consuming device is consuming more power than may be supplied by the primary power system.

6. The method of claim 1, wherein beginning production of the system electrical output includes supplying the electrical output from at least one of the plurality of fuel cell stacks, and further wherein initiating production of electrical output includes supplying the fuel stream and the oxidant stream to at least one of the plurality of fuel cell stacks and producing the stack electrical output therefrom.

7. The method of claim 1, wherein the first stack start time is between 1 and 1000 seconds and the second stack start time is between 1 and 1000 seconds.

8. The method of claim 1, wherein the method further comprises ceasing the production of electrical output from at least one of the first and second fuel cell stacks of the plurality of fuel cell stacks responsive to a stack stop condition.

9. The method of claim 8, wherein ceasing the production of electrical output includes at least one of ceasing the delivery of the fuel stream to at least one of the plurality of fuel cell stacks and electrically disconnecting the stack electrical output from the energy consuming device.

10. The method of claim 8, wherein the stack stop condition includes a first stack stop condition and the method includes ceasing the production of electrical output from one of the first fuel cell stack of the plurality of fuel cell stacks and the second fuel cell stack of the plurality of fuel cell stacks responsive to the first stack stop condition, and further wherein the stack stop condition includes a second stack stop condition and the method includes ceasing the production of electrical output from the other of the first fuel cell stack of the plurality of fuel cell stacks and the second fuel cell stack of the plurality of fuel cell stacks responsive to the second stack stop condition.

11. The method of claim 10, wherein at least one of the first stack stop condition and the second stack stop condition corresponds to a power output from the fuel cell system falling below a predetermined threshold level.

12. The method of claim 10, wherein the first stack stop condition includes the first stack stop condition being met for a first stack stop time threshold that is in the range of 1 and 1000 seconds, and further wherein the second stack stop condition includes the second stack stop condition being met for a second stack stop time threshold that is in the range of 1 and 1000 seconds.

13. The method of claim 8, wherein ceasing production of electrical output from at least one of the first fuel cell stack and the second fuel cell stack includes ceasing production of electrical output from both the first fuel cell stack and the second fuel cell stack responsive to an all stack stop condition.

14. The method of claim 13, wherein the all stack stop condition corresponds to a float level of charge of the energy storage device.

15. The method of claim 1, wherein, subsequent to initiating production of electrical output from the first fuel cell stack, the method further includes waiting for a threshold wait time prior to initiating production of electrical output from the second fuel cell stack.

16. The method of claim 1, wherein the first fuel cell stack includes a first stack output voltage and, subsequent to initiating production of electrical output from the first fuel cell stack, the method further includes waiting for the first stack output voltage to reach a threshold level prior to initiating production of electrical output from the second fuel cell stack.