HYDROGEN-PRODUCING FUEL CELL SYSTEMS WITH LOAD-RESPONSIVE FEEDSTOCK DELIVERY SYSTEMS

• US 20070264546A1
• Filed: 05/10/2007
• Published: 11/15/2007
• Est. Priority Date: 05/15/2006
• Status: Active Grant

• Current Assignee: DCNS SA (Government of France)
• Original Assignee: IdaTech LLC (IdaTech Ltd.)
• Inventors: LaVen, Arne
• Granted Patent: US 7,887,958 B2
• Time in Patent Office: Days
• US Class Current: 429/416
• CPC Class Codes: H01M 16/006 of fuel cells with rechargeable batteries
• CPC Class Codes: H01M 2008/1095 Fuel cells with polymeric electrolytes
• CPC Class Codes: H01M 8/04089 of gaseous reactants
• CPC Class Codes: H01M 8/04559 of fuel cell stacks
• CPC Class Codes: H01M 8/04589 of fuel cell stacks
• CPC Class Codes: H01M 8/04656 of auxiliary devices, e.g. batteries, capacitors
• CPC Class Codes: H01M 8/04753 of fuel cell reactants
• 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 8/0606 with means for production of gaseous reactants
• CPC Class Codes: H01M 8/0618 Reforming processes, e.g. autothermal, partial oxidation or steam reforming
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/50 Fuel cells
• CPC Class Codes: Y02P 90/40 Fuel cell technologies in production processes

Abstract

Hydrogen-producing fuel cell systems with load-responsive feedstock delivery systems, and methods for regulating the delivery of feedstock to the hydrogen-producing region of a fuel cell system. The fuel cell systems include a control system that is adapted to monitor and selectively regulate the rate at which the feedstock is delivered to a hydrogen-producing region of a hydrogen generation assembly. The control systems, and corresponding methods, include feed-forward and feedback control portions that cooperatively regulate the rate at which the feed stream is delivered to the hydrogen generation assembly responsive at least in part, if not completely, to the fuel cell stack'"'"'s demand for hydrogen gas and the rate at which the produced hydrogen gas is consumed by the fuel cell stack.

Claims

1. A fuel cell system, comprising:

a hydrogen generation assembly with a hydrogen-producing region that produces hydrogen gas from at least one feedstock;

a feedstock delivery system that delivers a feed stream containing the at least one feedstock to the hydrogen-generation assembly;

a fuel cell stack that receives hydrogen gas produced by the hydrogen-generation assembly and produces an electrical output therefrom to satisfy at least a portion of an applied load; and

a control system that is adapted to regulate the feed rate at which the feed stream is delivered to the hydrogen-producing region, wherein the control system includes a feed-forward control portion and a feedback control portion that cooperatively regulate the rate at which the feed stream is delivered to the hydrogen-producing region responsive at least in part to a demand for hydrogen gas by the fuel cell stack to satisfy the portion of the applied load;

wherein the feed-forward control portion estimates the flow rate of hydrogen gas required by the fuel cell stack to satisfy the portion of the applied load applied thereto by determining the portion of the applied load that is not being satisfied by the fuel cell stack using hydrogen gas produced by the hydrogen generation assembly, and further wherein the feedback control portion is adapted to adjust the flow rate of hydrogen gas estimated by the feed-forward control portion responsive to the rate at which the hydrogen gas produced by the hydrogen generation assembly is consumed by the fuel cell stack.

2. The fuel cell system of claim 1, wherein the feed-forward control portion is adapted to estimate the flow rate of hydrogen gas required by the fuel cell stack by selecting a feed rate for the feed stream responsive at least in part to a comparison of the voltage of the electrical output of the fuel cell stack to a predetermined output voltage.

3. The fuel cell system of claim 2, wherein the comparison includes adjusting the estimated flow rate of hydrogen gas responsive to the impedance of an energy-storage device associated with the fuel cell system.

4. The fuel cell system of claim 2, wherein the comparison includes adjusting the estimated flow rate of hydrogen gas responsive to the current of the electrical output of the fuel cell stack.

5. The fuel cell system of claim 1, wherein the feed-forward control portion is further adapted to predict a future demand for hydrogen gas by the fuel cell stack and to selectively adjust the estimated flow rate of hydrogen gas responsive thereto.

6. The fuel cell system of claim 1, wherein the control system is adapted to monitor and selectively regulate the rate at which the feed stream is delivered to the hydrogen-producing region responsive at least in part to the load applied to the fuel cell system by an energy-consuming assembly.

7. The fuel cell system of claim 1, wherein the feedback control portion monitors an operating parameter of the fuel cell system that is indicative of the feedstock delivery system delivering more or less feedstock than is needed to produce the required amount of hydrogen gas.

8. The fuel cell system of claim 7, wherein the operating parameter is the pressure of the hydrogen gas produced by the hydrogen-producing region.

9. The fuel cell system of claim 1, wherein the feedback control portion is adapted to adjust the feed rate estimated by the feed-forward portion in predetermined incremental amounts.

10. The fuel cell system of claim 1, wherein the feedback control portion is adapted to adjust the feed rate estimated by the feed-forward portion in predetermined percentages of the feed rate.

11. The fuel cell system of claim 1, wherein the control system includes a controller that is in communication with a sensor assembly, and wherein the sensor assembly is adapted to measure selected operating parameters of the fuel cell system.

12. The fuel cell system of claim 11, wherein the control system is adapted to monitor and selectively regulate the rate at which the feed stream is delivered to the hydrogen-producing region responsive at least in part to the parameters measured by the sensor assembly.

13. The fuel cell system of claim 1, wherein the feed stream contains water and a carbon-containing feedstock.

14. A method for controlling the flow rate of feedstock delivered to a hydrogen-producing region of a hydrogen-producing fuel cell system containing a fuel cell stack, the method comprising:

regulating the flow rate of feedstock to the hydrogen-producing region of a hydrogen generation assembly by cooperatively;

estimating the flow rate of feedstock required to produce sufficient hydrogen gas for the fuel cell stack to produce an electrical output to satisfy an applied load that is applied to the fuel cell stack, wherein the estimating is based at least in part upon determining a portion of the applied load that is not being satisfied by the fuel cell stack using hydrogen gas generated by the hydrogen generation assembly; and

adjusting the estimated flow rate of feedstock responsive to the rate at which the hydrogen gas produced by the hydrogen generation assembly is consumed by the fuel cell stack.

15. The method of claim 14, wherein the estimating further includes predicting a future demand for hydrogen gas by the fuel cell stack and adjusting the estimated flow rate of hydrogen gas responsive thereto.

16. The method of claim 14, wherein the estimating includes selecting a feed rate for the feed stream responsive at least in part to a comparison of the voltage of the electrical output of the fuel cell stack to a predetermined output voltage.

17. The method of claim 16, wherein the comparison includes adjusting the estimated flow rate of hydrogen gas responsive to the impedance of an energy-storage device associated with the fuel cell system.

18. The method of claim 16, wherein the comparison includes adjusting the estimated flow rate of hydrogen gas responsive to the current of the electrical output of the fuel cell stack.

19. The method of claim 14, wherein the method includes monitoring and selectively regulating the flow rate at which the feedstock is delivered to the hydrogen-producing region responsive at least in part to the load applied to the fuel cell system by an energy-consuming assembly.

20. The method of claim 14, wherein the adjusting includes monitoring an operating parameter of the fuel cell system that is indicative of the feedstock delivery system delivering more or less feedstock than is needed to produce the required amount of hydrogen gas.

21. The method of claim 20, wherein the operating parameter is the pressure of the hydrogen gas produced by the hydrogen-producing region.

22. The method of claim 14, wherein the adjusting includes adjusting the feed rate estimated by the feed-forward portion in predetermined incremental amounts.

23. The method of claim 14, wherein the adjusting includes adjusting the feed rate estimated by the feed-forward portion in predetermined percentages of the feed rate.

24. A fuel cell system, comprising:

a hydrogen generation assembly with a hydrogen-producing region that produces hydrogen gas from at least one feedstock;

a feedstock delivery system that delivers a feed stream containing the at least one feedstock to the hydrogen-generation assembly;

a fuel cell stack that receives hydrogen gas produced by the hydrogen-generation assembly and produces an electrical output therefrom to satisfy at least a portion of an applied load; and

control means for regulating the feed rate at which the feed stream is delivered to the hydrogen-producing region, wherein the control means includes feed-forward control means and feedback control means that cooperatively regulate the rate at which the feed stream is delivered to the hydrogen-producing region responsive at least in part to a demand for hydrogen gas by the fuel cell stack to satisfy the portion of the applied load;

wherein the feed-forward control means estimates the flow rate of hydrogen gas required by the fuel cell stack to satisfy the portion of the applied load applied thereto, and further wherein the feedback control means adjusts the flow rate of hydrogen gas estimated by the feed-forward control portion responsive to the rate at which the hydrogen gas produced by the hydrogen generation assembly is consumed by the fuel cell stack.

25. The fuel cell system of claim 24, wherein the feed-forward control means estimates the rate at which the feed stream is delivered to the hydrogen-producing region responsive to the formula: