Utilization-based fuel cell monitoring and control

• US 20050266285A1
• Filed: 04/18/2005
• Published: 12/01/2005
• Est. Priority Date: 05/28/2004
• Status: Active Grant

• Current Assignee: DCNS SA (Government of France)
• Original Assignee: IdaTech LLC (IdaTech Ltd.)
• Inventors: Scharf, Mesa, Edlund, David J., LaVen, Arne
• Granted Patent: US 7,985,510 B2
• Time in Patent Office: Days
• US Class Current: 429/416
• CPC Class Codes: H01M 8/04089 of gaseous reactants
• CPC Class Codes: H01M 8/04402 of anode exhausts
• CPC Class Codes: H01M 8/04589 of fuel cell stacks
• CPC Class Codes: H01M 8/04753 of fuel cell reactants
• CPC Class Codes: H01M 8/0612 from carbon-containing material
• CPC Class Codes: H01M 8/0662 Treatment of gaseous reactants or gaseous residues, e.g. cleaning
• 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

Fuel cell systems and methods for controlling the operation of components of the fuel cell system, which may include a fuel source and a fuel cell stack. In some examples, a fuel source is adapted to provide supply fuel to a fuel cell stack at a supply pressure. The fuel cell stack produces electric current at a production amperage. In some examples, a control system is adapted to control operation of the fuel cell stack based on a pressure detected at the fuel cell stack. In some examples, a target production amperage is determined based on the detected pressure, such that when electric current is produced at the target production amperage for the detected pressure, the fuel cell stack consumes a predetermined proportion of the supply fuel.

Claims

1. An energy producing and consuming assembly comprising:

a fuel source adapted to provide supply fuel at a supply pressure;

a fuel cell stack including at least one fuel cell, wherein the fuel cell stack is adapted to receive the supply fuel and to produce electric current at a production amperage from the received supply fuel in response to an applied load;

a load applying assembly adapted to be controlled to apply a load to the fuel cell stack; and

a control system adapted to detect a pressure at the fuel cell stack and to control the electric current production based on the detected pressure by actively controlling the load applying assembly.

2. The energy producing and consuming assembly of claim 1, wherein the control system is further adapted to detect the production amperage, to determine a target production amperage based on the detected pressure, and to control the load applying assembly based on the detected production amperage and the target production amperage.

3. The energy producing and consuming assembly of claim 2, wherein the fuel cell stack, when producing the target production amperage, is adapted to consume a predetermined proportion of the supply fuel for the detected pressure.

4. The energy producing and consuming assembly of claim 3, wherein the predetermined proportion of supply fuel consumed by the fuel cell stack is in the range of about 70% and about 90%.

5. The energy producing and consuming assembly of claim 4, wherein the predetermined proportion of supply fuel consumed by the fuel cell stack is about 83%.

6. The energy producing and consuming assembly of claim 1, in which the fuel source is adapted to be controlled and the control system is further adapted to detect the production amperage, to determine a target production amperage, and to control the fuel source to provide the supply fuel at a supply pressure based on the target production amperage.

7. The energy producing and consuming assembly of claim 6, in which the control system is further adapted to determine a target flow of supply fuel based on the target production amperage and the detected pressure.

8. The energy producing and consuming assembly of claim 7, in which the fuel source is adapted to produce the supply fuel from one or more feedstocks, and the control system is further adapted to control operation of the fuel source based on the determined target flow of supply fuel.

9. The energy producing and consuming assembly of claim 1, in which the control system is adapted to determine unused fuel flow by utilizing the equation F=K{square root}{square root over (P)}, where F is the flow of unused fuel, K is a constant, and P is the pressure.

10. The energy producing and consuming assembly of claim 6, further comprising a pressure regulator adapted to actively control the supply pressure, wherein the control system is adapted to control the pressure regulator to maintain the supply pressure below a predetermined threshold pressure.

11. The energy producing and consuming assembly of claim 1, wherein the fuel source includes a fuel processor adapted to produce the supply fuel from at least one feedstock.

12. The energy producing and consuming assembly of claim 11, wherein the control system is adapted to control production of the supply fuel by the fuel processor to maintain the supply pressure below a first threshold, and to control electric current production by the fuel cell stack to maintain the supply pressure above a second threshold.

13. The energy producing and consuming assembly of claim 1, wherein the fuel cell stack is adapted to substantially continuously exhaust unused fuel from an exit orifice at an exit pressure, and wherein the pressure detected by the control system includes the exit pressure.

14. An energy producing and consuming assembly comprising:

a fuel source adapted to provide supply fuel at a supply pressure;

a fuel cell stack including at least one fuel cell, wherein the fuel cell stack is adapted to receive supply fuel from the fuel source at the supply pressure and to use at least a portion of the received supply fuel to produce electric current at a production amperage in response to an applied load;

a load applying device adapted to be controlled to apply a load on the fuel cell stack; and

a control system adapted to detect a pressure at the fuel cell stack, to determine a target production amperage at which the fuel cell stack consumes a predetermined proportion of the supply fuel for the detected pressure, to control operation of the fuel cell stack based on the target production amperage; and

to control the production amperage by actively controlling the load applying device.

15. The energy producing and consuming assembly of claim 14, wherein the predetermined proportion of supply fuel consumed by the fuel cell stack is in the range of about 70% and about 90%.

16. The energy producing and consuming assembly of claim 14, wherein the control system is further adapted to determine a target flow of supply fuel based on the target production amperage and the detected pressure, wherein the fuel source is adapted to be controlled to produce the supply fuel from one or more feedstocks, and wherein the control system is adapted to control use of the feedstocks by the fuel source based on the target flow of supply fuel.

17. The energy producing and consuming assembly of claim 16, wherein the fuel source includes a fuel processor adapted to produce the supply fuel, and further wherein the control system is adapted to control production of the supply fuel by the fuel processor to maintain the supply pressure below a first threshold, and to control electric current production by the fuel cell stack to maintain the supply pressure above a second threshold.

18. The energy producing and consuming assembly of claim 14, wherein the fuel cell stack is adapted to discharge unused fuel intermittently.

19. The energy producing and consuming assembly of claim 14, wherein the fuel cell stack is adapted to substantially continuously exhaust unused fuel from an exit orifice at an exit pressure, and wherein the pressure detected by the control system includes the exit pressure.

20. A method of operating an energy producing and consuming assembly, comprising:

producing a supply fuel at a supply pressure;

applying oxidant and the supply fuel to a fuel cell stack, which includes at least one fuel cell, and which is adapted to produce electric current therefrom at a production amperage;

applying a load to the fuel cell stack to draw electric current from the fuel cell stack;

detecting a pressure at the fuel cell stack; and

controlling the production amperage based on the detected pressure by actively controlling the load applied to the fuel cell stack.

21. The method of claim 20, further comprising determining unused fuel flow based on the detected pressure, wherein determining unused fuel flow includes solving the equation F=K{square root}{square root over (P)}, where F is the flow of unused fuel, K is a constant, and P is the detected pressure.

22. The method of claim 20, further comprising detecting the production amperage, and determining a target production amperage at which the fuel cell stack consumes a predetermined proportion of the supply fuel for the detected pressure, and wherein controlling the production amperage is based at least in part on the determined target production amperage.

23. The method of claim 22, further comprising determining a target flow of supply fuel based on the target production amperage and the detected pressure, and controlling production of the supply fuel based on the target flow of supply fuel.

24. The method of claim 23, wherein producing a supply fuel includes producing the supply fuel from one or more feedstocks, and further comprising controlling the use of the feedstocks based on the target flow of supply fuel.

25. The method of claim 22, wherein the predetermined proportion of supply fuel consumed at the target production amperage is in the range of about 70% and about 90%.

26. The method of claim 25, wherein the predetermined proportion of supply fuel consumed at the target production amperage is about 83%.

27. The method of claim 20, wherein applying a load to the fuel cell stack includes conducting electric current from the fuel cell stack to a load applying assembly.

28. The method of claim 20, further comprising substantially continuously discharging unused fuel from the fuel cell stack through an exit orifice at an exit pressure, and wherein detecting a pressure at the fuel cell stack includes detecting the exit pressure.

29. The method of claim 20, wherein producing a supply fuel includes producing the supply fuel from one or more feedstocks;

and further comprising controlling the production of the supply fuel in a manner adapted to maintain the supply pressure below a first threshold value, and controlling the production of electric current by the fuel cell stack in a manner adapted to maintain the supply pressure above a second threshold value that is less than the first threshold value.

30. A method of operating an energy producing and consuming assembly, comprising:

supplying a supply fuel at a supply pressure;

applying oxidant and the supply fuel to a fuel cell stack, which includes at least one fuel cell;

producing electric current with the fuel cell stack at a production amperage;

detecting a pressure at the fuel cell stack;

determining a target production amperage at which the fuel cell stack consumes a predetermined proportion of the supply fuel for the detected pressure; and

controlling the operation of the fuel cell stack based on the target production amperage.

31. The method of claim 30, further comprising applying a load to the fuel cell stack, and wherein controlling the operation of the fuel cell stack includes actively controlling the load applied to the fuel cell stack.

32. The method of claim 31, wherein providing supply fuel includes applying one or more feedstocks to a fuel processor apparatus in a manner producing the supply fuel at a supply pressure, and further comprising controlling the operation of the fuel processor apparatus based at least in part on the target production amperage.

33. The method of claim 30, further comprising discharging unused fuel from the fuel cell stack intermittently.

34. The method of claim 30, further comprising substantially continuously discharging unused fuel from the fuel cell stack through an exit orifice at an exit pressure, and wherein detecting a pressure at the fuel cell stack includes detecting the exit pressure.

35. The method of claim 30, wherein supplying a supply fuel at a supply pressure includes producing the fuel from one or more feedstocks;

and further comprising controlling the production of the supply fuel in a manner adapted to maintain the supply pressure below a first threshold value, and controlling the production of electric current by the fuel cell stack in a manner adapted to maintain the supply pressure above a second threshold value that is less than the first threshold value.