Electrochemical system and methods for control thereof

• US 20030143440A1
• Filed: 11/20/2002
• Published: 07/31/2003
• Est. Priority Date: 11/20/2001
• Status: Active Grant

• Current Assignee: Sofc Holdings LLC
• Original Assignee: CellTech Power LLC
• Inventors: Bai, Wei, Blake, Adam P., Tao, Tao T., Rackey, Scott C.
• Granted Patent: US 7,229,710 B2
• Time in Patent Office: Days
• US Class Current: 429/13
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H01M 16/003 of fuel cells with other electrochemical devices, e.g. capacitors, electrolysers
• CPC Class Codes: H01M 8/04089 of gaseous reactants
• CPC Class Codes: H01M 8/04186 of liquid-charged or electrolyte-charged reactants
• CPC Class Codes: H01M 8/04194 Concentration measuring cells
• CPC Class Codes: H01M 8/04343 of anode exhausts
• CPC Class Codes: H01M 8/0435 of cathode exhausts
• CPC Class Codes: H01M 8/04447 of anode reactants at the inlet or inside the fuel cell
• CPC Class Codes: H01M 8/04559 of fuel cell stacks
• CPC Class Codes: H01M 8/04589 of fuel cell stacks
• CPC Class Codes: H01M 8/04619 of fuel cell stacks
• CPC Class Codes: H01M 8/04649 of fuel cell stacks
• CPC Class Codes: H01M 8/04753 of fuel cell reactants
• CPC Class Codes: H01M 8/1011 Direct alcohol fuel cells [DAFC], e.g. direct methanol fuel cells [DMFC]
• CPC Class Codes: H01M 8/18 Regenerative fuel cells, e.g. redox flow batteries or secondary fuel cells
• 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

The present invention relates to an electrochemical device. The device features an anode constructed of materials such that the device can be chemically recharged. In addition, the device is capable of switching between operating as a fuel cell or as a battery. In certain aspects of the invention, the device includes a liquid anode and is capable of operating at a temperature of less than 1000° C. Other aspects feature a control system and a fuel delivery system for the electrochemical system.

Claims

1. A method, comprising:

measuring a property of an electrochemical system;

correlating the measured property to a concentration of an anode species in an anode of an electrochemical device associated with the electrochemical system; and

controlling the introduction of at least one of a fuel and oxygen to the electrochemical device based at least in part upon the concentration of the anode species in the anode of the electrochemical device.

2. The method of claim 1, wherein the measured property is selected from the group consisting of a concentration of an indicator species in an exhaust from the electrochemical device, a current generated by the electrochemical device, a voltage of the electrochemical device, an AC impedance profile of the electrochemical device, a resistance of the electrochemical device, a power output of the electrochemical device, a fuel efficiency of the electrochemical device, a fuel utilization of the electrochemical device, and combinations thereof.

3. The method of claim 1, wherein measuring a property of an electrochemical system comprises measuring a property of an exhaust from the electrochemical device

4. The method of claim 3, wherein measuring a property of the exhaust comprises measuring the concentration of at least one species in the exhaust.

5. The method of claim 4, wherein measuring a property of the exhaust comprises measuring a property of an anode exhaust and wherein the at least one species is selected from the group consisting of carbon monoxide, hydrogen, carbon dioxide, sulfur oxides, nitrogen oxides, volatile organic compounds, hydrogen sulfide, and combinations thereof.

6. The method of claim 4, wherein measuring a property of the exhaust comprises measuring a property of a cathode exhaust and wherein the at least one species is oxygen.

7. The method of claim 3, wherein measuring a property of the exhaust comprises measuring the temperature of the exhaust.

8. The method of claim 1, further comprising:

flowing a fuel into a bottom portion of an anode compartment of the electrochemical device, the anode compartment having the bottom portion and a wall ascending from the bottom portion;

forming a bubble of the fuel on the bottom portion of the anode compartment until the bubble contacts the wall of the anode compartment; and

allowing the bubble to travel up the wall of the anode compartment.

9. The method of claim 1, further comprising:

flowing the fuel into the electrochemical device through a restriction sized and adapted to provide an upstream to downstream pressure ratio across the restriction of at least 1.1;

1.

10. The method of claim 9, wherein the upstream to downstream pressure ratio across the restriction is at least 1.25:

1.

11. The method of claim 10, further comprising flowing the fuel into the electrochemical device through a restriction comprising an orifice under critical flow conditions.

12. The method of claim 9, further comprising:

supplying the fuel to a common reservoir; and

flowing the fuel through a plurality of restrictions each associated with at least one of a plurality of electrochemical devices.

13. The method of claim 12, further comprising:

varying a flow rate of fuel through the plurality of restrictions by varying the pressure in the common reservoir.

14. The method claim 1, wherein the anode is a liquid anode.

15. The method of claim 1, wherein the anode is a chemically rechargeable anode.

16. An electrochemical system, comprising:

an electrochemical device comprising an anode, a cathode, and an electrolyte, the electrochemical device connectable to a fuel delivery system constructed and arranged to provide fuel to the electrochemical device, and connectable to an oxygen delivery system constructed and arranged to provide oxygen to the electrochemical device; and

a control system, comprising;

a sensor constructed and arranged to measure a property of the electrochemical device and produce a sensor signal representing the property, and

a controller constructed and arranged to receive the sensor signal from the sensor, correlate the sensor signal to a concentration of an anode species in the anode, and provide a control signal to at least one of the fuel delivery system and the oxygen delivery system based, at least in part, on the concentration of the anode species in the anode.

17. The electrochemical system of claim 16, wherein the property is selected from the group consisting of a concentration of an indicator species in an exhaust from the electrochemical device, a current generated by the electrochemical device, a voltage of the electrochemical device, an AC impedance profile of the electrochemical device, a resistance of the electrochemical device, a power output of the electrochemical device, a fuel efficiency of the electrochemical device, a fuel utilization of the electrochemical device, and combinations thereof.

18. The electrochemical system of claim 16, wherein the sensor is constructed and arranged to measure a property of an exhaust from the electrochemical device.

19. The electrochemical system of claim 18, wherein the property of the exhaust comprises the concentration of at least one species in the exhaust.

20. The electrochemical system of claim 19, wherein the exhaust comprises an anode exhaust and the at least one species is selected from the group consisting of carbon monoxide, hydrogen, carbon dioxide, sulfur oxides, nitrogen oxides, volatile organic compounds, hydrogen sulfide, and combinations thereof.

21. The electrochemical system of claim 19, wherein the exhaust comprises a cathode exhaust and the at least one species is oxygen.

22. The electrochemical system of claim 18, wherein the property is the temperature of the exhaust.

23. The electrochemical system of claim 16, wherein the sensor is constructed and arranged to measure a property that is at least one of an open circuit voltage, a current, an AC impedance, a power output and a resistance of the electrochemical device

24. The electrochemical system of claim 16, wherein the electrochemical device comprises an anode compartment constructed and arranged to at least partially contain a liquid anode, the fuel delivery system comprises a feed conduit fluidly connected to the anode compartment, and the electrochemical system further comprises an anode flow prevention device associated with the feed conduit.

25. The electrochemical system of claim 24, further comprising a liquid anode positioned at least partially within the anode compartment.

26. The electrochemical system of claim 24, wherein the anode flow prevention device is positioned at the end of the feed conduit.

27. The electrochemical system of claim 24, wherein the anode flow prevention device is porous.

28. The electrochemical system of claim 27, wherein a largest pore in the anode flow prevention device is less than 3 millimeters.

29. The electrochemical device of claim 27, wherein an average pore diameter of the anode prevention device is less than about 0.3 millimeter.

30. The electrochemical device of claim 29, wherein a largest pore diameter of the anode prevention device is less than about 0.3 millimeter.

31. The electrochemical system of claim 27, wherein pores in the anode prevention device are sized and shaped such that the surface tension of the anode prevents the anode from entering the pores.

32. The electrochemical system of claim 24, wherein the feed conduit is fluidly connected to a bottom of portion of the anode compartment.

33. The electrochemical system of claim 24, wherein the feed conduit is fluidly connected to a top portion of the anode compartment.

34. The electrochemical system of claim 33, wherein the feed conduit extends into the top portion of the anode compartment toward a bottom portion of the anode compartment.

35. The electrochemical system of claim 24, wherein the feed conduit is fluidly connected to a side portion of the anode compartment.

36. The electrochemical system of claim 16, further comprising:

a fuel other than hydrogen, carbon monoxide, methane or a mixture thereof deliverable to the anode;

wherein the electrochemical system is free of a fuel reformer.

37. The electrochemical system of claim 36, wherein the fuel is selected from the group consisting of solids, liquids, and combinations thereof.

38. The electrochemical system of claim 16, further comprising:

a fuel including sulfur;

wherein the electrochemical system is free of a fuel desulfurizer.

39. The electrochemical system of claim 38, wherein the fuel comprises more than 10 parts per million sulfur.

40. The electrochemical system of claim 39, wherein the fuel comprises more than 100 parts per million sulfur.

41. The electrochemical system of claim 16, further comprising:

an exhaust conduit fluidly connected to the electrochemical device; and

a second electrochemical device comprising a fuel delivery system in fluid communication with the exhaust conduit.

42. The electrochemical system of claim 41, wherein the second electrochemical device is selected from the group consisting of a solid oxide fuel cell, a fuel cell comprising a chemically rechargeable anode, a fuel cell comprising a liquid anode, a molten carbonate fuel cell, and combinations thereof.

43. The electrochemical system of claim 16, further comprising:

an anti-coking agent selected from the group consisting of water, oxygen, carbon monoxide, carbon dioxide, and combinations thereof, deliverable to the fuel delivery system.

44. The electrochemical system of claim 43, wherein the anti-coking agent comprises an exhaust from the electrochemical device.

45. The electrochemical system of claim 43, further comprising a conduit fluidly connecting the exhaust to the fuel delivery system.

46. The electrochemical system of claim 16, further comprising:

an anti-coking agent comprising a material selected from the group consisting of copper, nickel, platinum, oxygen, ruthenium, cerium, rhodium, osmium, aluminum, calcium, magnesium, sodium, other alkaline metals, other rare earth metals, and mixtures thereof, the anti-coking agent associated with at least a portion of a feed conduit of the fuel delivery system.

47. The electrochemical system of claim 16, wherein the anode is a liquid anode.

48. The electrochemical system of claim 47, wherein the anode comprises a cold zone associated with the fuel delivery system.

49. The electrochemical system of claim 48, wherein the cold zone comprises a portion of a feed conduit from the fuel delivery system, the portion of the feed conduit being occupied by a portion of the anode.

50. The electrochemical system of claim 16, wherein the anode is a chemically rechargeable anode.

51. The electrochemical system of claim 16, further comprising:

an exhaust system; and

a heat exchanger connected to the exhaust system.

52. The electrochemical system of claim 51, wherein the heat exchanger is constructed and arranged to be connectable to a building heating system.

53. The electrochemical system of claim 52, further comprising:

a building heating system connected to the heat exchanger.

54. The electrochemical system of claim 51, wherein the heat exchanger is constructed and arranged to be connectable to a hot water supply system.

55. The electrochemical system of claim 54, further comprising:

a hot water supply system connected to the heat exchanger.

56. The electrochemical system of claim 16, further comprising:

an exhaust system; and

a combustion system connected to the exhaust system.

57. The electrochemical system of claim 56, wherein the exhaust system comprises a cathode exhaust and an anode exhaust and only the anode exhaust is connected to the combustion system.

58. The electrochemical system of claim 56, wherein the combustion system comprises an internal combustion engine.

59. The electrochemical system of claim 56, wherein the combustion system comprises a heat exchanger.

61. The electrochemical system of claim 16, further comprising:

an anode exhaust system; and

a carbon dioxide separation system connected to the anode exhaust system.

60. The electrochemical system of claim 71, further comprising an exhaust system connected to a turbine.