METAL-AIR ELECTROCHEMICAL CELL WITH HIGH ENERGY EFFICIENCY MODE

• US 20110250512A1
• Filed: 04/11/2011
• Published: 10/13/2011
• Est. Priority Date: 04/13/2010
• Status: Active Grant

• Current Assignee: Form Energy, Inc.
• Original Assignee: Fluidic, Inc.
• Inventors: Hayes, Joel, FRIESEN, Cody A., Krishnan, Ramkumar, Trimble, Todd
• Granted Patent: US 9,761,920 B2
• Time in Patent Office: Days
• US Class Current: 429/405
• CPC Class Codes: H01M 10/425 Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing printed circuits H05K1/00
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H01M 12/08 composed of a half-cell of a fuel-cell type and a half-cell of the secondary-cell type
• CPC Class Codes: H01M 16/00 Structural combinations of different types of electrochemical generators
• CPC Class Codes: H01M 2010/4271 Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing
• CPC Class Codes: H01M 2300/0014 Alkaline electrolytes
• CPC Class Codes: H01M 4/24 Electrodes for alkaline accumulators
• CPC Class Codes: H01M 4/244 Zinc electrodes
• CPC Class Codes: H01M 4/32 Nickel oxide or hydroxide electrodes
• CPC Class Codes: H01M 4/8615 Bifunctional electrodes for rechargeable cells
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

The present invention relates to a metal-air electrochemical cell with a high energy efficiency mode.

Claims

1. A metal-air electrochemical cell for storing electrical energy from a power source and supplying electrical energy to a load, comprising:

a plurality of electrodes comprising a fuel electrode comprising a metal fuel and an air electrode for exposure to an oxygen source, wherein an electrode of the plurality other than the fuel electrode comprises a reversible metal capable of reversible oxidation to a reducible species thereof and reduction to an oxidizable species thereof, and wherein an electrode of the plurality other than the fuel electrode has an oxygen evolving functionality;

an ionically conductive medium for conducting ions among the plurality of electrodes;

a controller configured to operate the cell in the following states;

(i) a standard recharge state wherein the power source is coupled to the fuel electrode and the oxygen evolving electrode for applying a potential difference therebetween to cause reduction of a reducible species of the metal fuel on the fuel electrode and evolution of oxygen from the ionically conductive medium at the oxygen evolving electrode;

(ii) a standard discharge state wherein the fuel electrode and the air electrode are coupled to the load such that oxidation of the metal fuel at the fuel electrode and reduction of oxygen from the oxygen source at the air electrode generates a potential difference for outputting current;

(iii) a high energy efficiency recharge state wherein the power source is coupled to the fuel electrode and the electrode comprising the reversible metal for applying a potential difference therebetween to cause reduction of a reducible species of the metal fuel on the fuel electrode and oxidizing the oxidizable species of the reversible metal, if present, to the reducible species thereof with the potential of the electrode comprising the reversible metal being cathodic of the potential for oxygen evolution; and

(iv) a high energy efficiency discharge state wherein the fuel electrode and the electrode comprising the reversible metal are coupled to the load such that oxidation of the metal fuel at the fuel electrode and reduction of the reducible species of the reversible metal, if present, to the oxidizable species thereof generates a potential difference for outputting current with the potential of the electrode reversible metal being anodic of the potential for oxygen reduction at the air electrode;

wherein an energy efficiency of the high energy efficiency discharge and recharge states is greater than an energy efficiency of the standard discharge and recharge states, each energy efficiency being the ratio of q_outV_out/q_inV_in.

2. A metal-air electrochemical cell according to claim 1, wherein the electrode comprising the reversible metal and the oxygen evolving electrode are the same electrode which is a tri-functional electrode separate from both the fuel electrode and the air electrode;

and

wherein the controller is switchable between;

(i) a recharge state coupling the power source to the fuel electrode and the tri-functional electrode such that the recharge state includes (a) initially the high energy recharge state in which oxidation at the tri-functional electrode is predominated by oxidation of the oxidizable species of the reversible metal, if present, to the reducible species thereof with the potential of the tri-functional electrode being cathodic of the potential for oxygen evolution, and (b) then the standard recharge state in which the oxidation at the tri-functional electrode is predominated by evolution of oxygen from the ionically conductive medium;

(ii) the standard discharge state; and

(iii) the high efficiency discharge state.

3. A metal-air electrochemical cell according to claim 1, wherein the electrode comprising the reversible metal and the oxygen evolving electrode are separate electrodes and are each separate from both the fuel electrode and the air electrode;

and

wherein the controller is switchable between;

(i) the standard recharge state;

(ii) the standard discharge state;

(iii) the high efficiency recharge state; and

(iv) the high efficiency discharge state.

4. A metal-air electrochemical cell according to claim 1, wherein the air electrode, the electrode comprising the reversible metal and the oxygen evolving electrode are the same electrode which is a quad-functional electrode, such that the load is coupled to the fuel electrode and the quad-functional electrode in both the standard and high efficiency discharge states and the power source is coupled to the fuel electrode and the quad-functional electrode in both the standard and high efficiency recharge states;

and

wherein the controller includes a regulator coupled to at least the quad-functional electrode to control the potential at the quad-functional electrode for setting its potential anodic of the potential for oxygen reduction during the high efficiency discharge state and cathodic of the potential for oxygen evolution during the high efficiency recharge state.

5. A metal-air electrochemical cell according to claim 1, wherein the reversible metal is a nickel species.

6. A metal-air electrochemical cell according to claim 5, wherein the oxidizable species of the nickel is Ni(OH)₂ and the reducible species of the nickel is NiOOH.

7. A metal-air electrochemical cell according to claim 1, wherein said controller is configured to switch between the states thereof based on predetermined criteria.

8. A metal-air electrochemical cell according to claim 1, wherein the fuel is selected from the group consisting of an alkaline earth metal, a transition metal, and a post-transition metal.

9. A metal-air electrochemical cell according to claim 1, wherein the fuel is selected from the group consisting of zinc, aluminum, magnesium, manganese, and iron.

10. A metal-air electrochemical cell according to claim 5, wherein the fuel is selected from the group consisting of an alkaline earth metal, a transition metal, and a post-transition metal.

11. A metal-air electrochemical cell according to claim 5, wherein the fuel is selected from the group consisting of zinc, aluminum, magnesium, manganese, and iron.

12. A metal-air electrochemical cell according to claim 6, wherein the fuel is selected from the group consisting of an alkaline earth metal, a transition metal, and a post-transition metal.

13. A metal-air electrochemical cell according to claim 6, wherein the fuel is selected from the group consisting of zinc, aluminum, magnesium, manganese, and iron.

14. A metal-air electrochemical cell according to claim 1, wherein the ionically conductive medium is an alkaline aqueous electrolyte solution.

15. A metal-air electrochemical cell according to claim 5, wherein the ionically conductive medium is an alkaline aqueous electrolyte solution.

16. A metal-air electrochemical cell according to claim 6, wherein the ionically conductive medium is an alkaline aqueous electrolyte solution.

17. A metal-air electrochemical cell according to claim 10, wherein the ionically conductive medium is an alkaline aqueous electrolyte solution.

18. A metal-air electrochemical cell according to claim 11, wherein the ionically conductive medium is an alkaline aqueous electrolyte solution.

19. A metal-air electrochemical cell according to claim 2, wherein the reversible metal is a nickel species.

20. A metal-air electrochemical cell according to claim 19, wherein the oxidizable species of the nickel is Ni(OH)₂ and the reducible species of the nickel is NiOOH.

21. A metal-air electrochemical cell according to claim 2, wherein said controller is configured to switch between the states thereof based on predetermined criteria.

22. A metal-air electrochemical cell according to claim 2, wherein the fuel is selected from the group consisting of an alkaline earth metal, a transition metal, and a post-transition metal.

23. A metal-air electrochemical cell according to claim 2, wherein the fuel is selected from the group consisting of zinc, aluminum, magnesium, manganese, and iron.

24. A metal-air electrochemical cell according to claim 19, wherein the fuel is selected from the group consisting of an alkaline earth metal, a transition metal, and a post-transition metal.

25. A metal-air electrochemical cell according to claim 19, wherein the fuel is selected from the group consisting of zinc, aluminum, magnesium, manganese, and iron.

26. A metal-air electrochemical cell according to claim 20, wherein the fuel is selected from the group consisting of an alkaline earth metal, a transition metal, and a post-transition metal.

27. A metal-air electrochemical cell according to claim 20, wherein the fuel is selected from the group consisting of zinc, aluminum, magnesium, manganese, and iron.

28. A metal-air electrochemical cell according to claim 2, wherein the ionically conductive medium is an alkaline aqueous electrolyte solution.

29. A metal-air electrochemical cell according to claim 19, wherein the ionically conductive medium is an alkaline aqueous electrolyte solution.

30. A metal-air electrochemical cell according to claim 20, wherein the ionically conductive medium is an alkaline aqueous electrolyte solution.

31. A metal-air electrochemical cell according to claim 24, wherein the ionically conductive medium is an alkaline aqueous electrolyte solution.

32. A metal-air electrochemical cell according to claim 25, wherein the ionically conductive medium is an alkaline aqueous electrolyte solution.

33. A metal-air electrochemical cell according to claim 3, wherein the reversible metal is a nickel species.

34. A metal-air electrochemical cell according to claim 33, wherein the oxidizable species of the nickel is Ni(OH)₂ and the reducible species of the nickel is NiOOH.

35. A metal-air electrochemical cell according to claim 3, wherein said controller is configured to switch between the states thereof based on predetermined criteria.

36. A metal-air electrochemical cell according to claim 3, wherein the fuel is selected from the group consisting of an alkaline earth metal, a transition metal, and a post-transition metal.

37. A metal-air electrochemical cell according to claim 3, wherein the fuel is selected from the group consisting of zinc, aluminum, magnesium, manganese, and iron.

38. A metal-air electrochemical cell according to claim 33, wherein the fuel is selected from the group consisting of an alkaline earth metal, a transition metal, and a post-transition metal.

39. A metal-air electrochemical cell according to claim 33, wherein the fuel is selected from the group consisting of zinc, aluminum, magnesium, manganese, and iron.

40. A metal-air electrochemical cell according to claim 34, wherein the fuel is selected from the group consisting of an alkaline earth metal, a transition metal, and a post-transition metal.

41. A metal-air electrochemical cell according to claim 34, wherein the fuel is selected from the group consisting of zinc, aluminum, magnesium, manganese, and iron.

42. A metal-air electrochemical cell according to claim 3, wherein the ionically conductive medium is an alkaline aqueous electrolyte solution.

43. A metal-air electrochemical cell according to claim 33, wherein the ionically conductive medium is an alkaline aqueous electrolyte solution.

44. A metal-air electrochemical cell according to claim 34, wherein the ionically conductive medium is an alkaline aqueous electrolyte solution.

45. A metal-air electrochemical cell according to claim 38, wherein the ionically conductive medium is an alkaline aqueous electrolyte solution.

46. A metal-air electrochemical cell according to claim 39, wherein the ionically conductive medium is an alkaline aqueous electrolyte solution.

47. A metal-air electrochemical cell according to claim 4, wherein the reversible metal is a nickel species.

48. A metal-air electrochemical cell according to claim 47, wherein the oxidizable species of the nickel is Ni(OH)₂ and the reducible species of the nickel is NiOOH.

49. A metal-air electrochemical cell according to claim 4, wherein said controller is configured to switch between the states thereof based on predetermined criteria.

50. A metal-air electrochemical cell according to claim 4, wherein the fuel is selected from the group consisting of an alkaline earth metal, a transition metal, and a post-transition metal.

51. A metal-air electrochemical cell according to claim 4, wherein the fuel is selected from the group consisting of zinc, aluminum, magnesium, manganese, and iron.

52. A metal-air electrochemical cell according to claim 47, wherein the fuel is selected from the group consisting of an alkaline earth metal, a transition metal, and a post-transition metal.

53. A metal-air electrochemical cell according to claim 47, wherein the fuel is selected from the group consisting of zinc, aluminum, magnesium, manganese, and iron.

54. A metal-air electrochemical cell according to claim 48, wherein the fuel is selected from the group consisting of an alkaline earth metal, a transition metal, and a post-transition metal.

55. A metal-air electrochemical cell according to claim 48, wherein the fuel is selected from the group consisting of zinc, aluminum, magnesium, manganese, and iron.

56. A metal-air electrochemical cell according to claim 4, wherein the ionically conductive medium is an alkaline aqueous electrolyte solution.

57. A metal-air electrochemical cell according to claim 47, wherein the ionically conductive medium is an alkaline aqueous electrolyte solution.

58. A metal-air electrochemical cell according to claim 48, wherein the ionically conductive medium is an alkaline aqueous electrolyte solution.

59. A metal-air electrochemical cell according to claim 52, wherein the ionically conductive medium is an alkaline aqueous electrolyte solution.

60. A metal-air electrochemical cell according to claim 53, wherein the ionically conductive medium is an alkaline aqueous electrolyte solution.

69. A method according to claim 1, wherein the ionically conductive medium is an alkaline aqueous electrolyte solution.

61. A method for operating an electrochemical cell for storing energy from a power source and supplying energy to a load, the cell comprising a plurality of electrodes comprising a fuel electrode comprising a metal fuel and an air electrode, wherein an electrode of the plurality other than the fuel electrode comprises a reversible metal capable of reversible oxidation to a reducible species thereof and reduction to an oxidizable species thereof, and wherein an electrode of the plurality other than the fuel electrode has an oxygen evolving functionality;

the method comprising;

operating the cell in the following states;

(i) a standard recharge state wherein the power source is coupled to the fuel electrode and the oxygen evolving electrode for applying a potential difference therebetween to cause reduction of a reducible species of the metal fuel on the fuel electrode and evolution of oxygen from the ionically conductive medium at the oxygen evolving electrode;

(ii) a standard discharge state wherein the fuel electrode and the air electrode are coupled to the load such that oxidation of the metal fuel at the fuel electrode and reduction of oxygen from the oxygen source at the air electrode generates a potential difference for outputting current;

(iii) a high energy efficiency recharge state wherein the power source is coupled to the fuel electrode and the electrode comprising the reversible metal for applying a potential difference therebetween to cause reduction of a reducible species of the metal fuel on the fuel electrode and oxidizing the oxidizable species of the reversible metal, if present, to the reducible species thereof with the potential of the electrode comprising the reversible metal being cathodic of the potential for oxygen evolution; and

(iv) a high energy efficiency discharge state wherein the fuel electrode and the electrode comprising the reversible metal are coupled to the load such that oxidation of the metal fuel at the fuel electrode and reduction of the reducible species of the reversible metal, if present, to the oxidizable species thereof generates a potential difference for outputting current with the potential of the electrode reversible metal being anodic of the potential for oxygen reduction at the air electrode;

wherein an energy efficiency of the high energy efficiency discharge and recharge states is greater than an energy efficiency of the standard discharge and recharge states, each energy efficiency being the ratio of q_outV_out/q_inV_in.

62. A method according to claim 61, wherein the electrode comprising the reversible metal and the oxygen evolving electrode are the same electrode which is a tri-functional electrode separate from both the fuel electrode and the air electrode;

and

wherein operating the cell in the standard and high efficiency recharge states comprises operating the cell in a recharge state coupling the power source to the fuel electrode and the tri-functional electrode such that the recharge state includes (a) initially the high energy recharge state in which oxidation at the tri-functional electrode is predominated by oxidation of the oxidizable species of the reversible metal, if present, to the reducible species thereof with the potential of the tri-functional electrode being cathodic of the potential for oxygen evolution, and (b) then the standard recharge state in which the oxidation at the tri-functional electrode is predominated by evolution of oxygen from the ionically conductive medium.

63. A method according to claim 61, wherein the electrode comprising the reversible metal and the oxygen evolving electrode are separate electrodes and are each separate from both the fuel electrode and the air electrode.

64. A method according to claim 61, wherein the air electrode, the electrode comprising the reversible metal and the oxygen evolving electrode are the same electrode which is a quad-functional electrode, such that the load is coupled to the fuel electrode and the quad-functional electrode in both the standard and high efficiency discharge states and the power source is coupled to the fuel electrode and the quad-functional electrode in both the standard and high efficiency recharge states;

and

wherein a regulator is coupled to at least the quad-functional electrode to control the potential at the quad-functional electrode for setting its potential anodic of the potential for oxygen reduction during the high efficiency discharge state and cathodic of the potential for oxygen evolution during the high efficiency recharge state.

65. A method according to claim 61, wherein the reversible metal is a nickel species.

66. A method according to claim 65, wherein the oxidizable species of the nickel is Ni(OH)₂ and the reducible species of the nickel is NiOOH.

67. A method according to claim 61, wherein the fuel is selected from the group consisting of an alkaline earth metal, a transition metal, and a post-transition metal.

68. A method according to claim 61, wherein the fuel is selected from the group consisting of zinc, aluminum, magnesium, manganese, and iron.