Electrochemical cell, and particularly a metal fueled cell with non-parallel flow

• US 8,168,337 B2
• Filed: 04/01/2009
• Issued: 05/01/2012
• Est. Priority Date: 04/04/2008
• Status: Active Grant

• Current Assignee: Arizona Board of Regents (University of Arizona)
• Original Assignee: Arizona Board of Regents (University of Arizona)
• Inventors: Friesen, Cody A., Hayes, Joel R.
• Primary Examiner(s): Ridley, Basia
• Assistant Examiner(s): Buchanan, Jacob
• Application Number:
  US12/385,217
• Publication Number:
  US 20110039181A1
• Time in Patent Office: 1,126 Days
• Field of Search: 429402-407, 429/452, 429/463, 429498-503
• US Class Current: 429/402
• CPC Class Codes: H01M 8/0656 by electrochemical means H01M8/065 takes precedence
• CPC Class Codes: H01M 8/08 Fuel cells with aqueous electrolytes
• CPC Class Codes: H01M 8/225 Fuel cells in which the fuel is based on materials comprising particulate active material in the form of a suspension, a dispersion, a fluidised bed or a paste
• CPC Class Codes: H01M 8/2455 with liquid, solid or electrolyte-charged reactants
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

The present invention relates to an electrochemical cell for use with an electrolyte, oxidizable solid fuel, and an oxidizer to generate electrical power. The electrochemical cell includes a permeable electrode body provided along a flow path for receiving a flow including an electrolyte. The permeable electrode body is configured to permit the electrolyte to flow therethrough and to collect solid fuel thereon from the electrolyte flowing therethrough so as to comprise a first electrode for oxidizing the fuel to generate electrons for conduction by the first electrode. The cell also includes a second electrode for receiving electrons and reducing an oxidizer. The first electrode and the second electrode are spaced apart to define a gap therebetween for receiving the flow from the permeable electrode body. One or more return channels are directly communicated to the gap.

Claims

1. An electrochemical cell for use with an electrolyte, oxidizable solid fuel, and an oxidizer to generate electrical power, the electrochemical cell comprising:

a permeable electrode body provided along a flow path for receiving a flow comprising at least the electrolyte, the permeable electrode body being configured to permit the electrolyte to flow therethrough, the permeable electrode body also being configured to collect the solid fuel thereon from the electrolyte flowing therethrough so as to comprise a first electrode for oxidizing the fuel to generate electrons for conduction by the first electrode;

a second electrode for receiving electrons and reducing an oxidizer;

the first electrode and the second electrode being spaced apart to define a gap therebetween for receiving the flow from the permeable electrode body;

a plurality of return channels directly communicated to the gap and disposed radially outward from the permeable electrode body; and

a flow generator configured to generate the flow comprising at least the electrolyte (i) through the permeable electrode body and towards the second electrode across the gap to transport at least the electrolyte and the oxidized fuel ions away from the permeable electrode body and towards the second electrode, and (ii) then through the plurality of return channels to transport at least the electrolyte and any by-product formed in the gap by the reaction of the oxidized fuel ions and the reduced oxidizer ions away from the gap without flowing through the second electrode.

2. An electrochemical cell according to claim 1, further comprising a supply containing the electrolyte and the solid fuel separately or together.

3. An electrochemical cell according to claim 2, wherein the solid fuel is selected from the group consisting of iron, zinc, magnesium, aluminum, and lithium.

4. An electrochemical cell according to claim 3, wherein the solid fuel is zinc.

5. An electrochemical cell according to claim 2, wherein the electrolyte comprises at least one aqueous solution selected from the group consisting of sulfuric acid, phosphoric acid, triflic acid, nitric acid, potassium hydroxide, sodium hydroxide, sodium chloride, potassium nitrate, and lithium chloride.

6. An electrochemical cell according to claim 5, wherein the electrolyte comprises potassium hydroxide.

7. An electrochemical cell according to claim 1 for use with oxidizable solid fuel particulates, wherein the permeable electrode body is a filter body configured to filter the fuel particulates from the electrolyte for collecting the fuel thereon.

8. An electrochemical cell according to claim 7, wherein the filter body comprises a carbon filter, a brass screen, or a bronze screen.

9. An electrochemical cell according to claim 1, wherein second electrode is a gas permeable electrode, having an outer surface exposed to ambient air such that the oxidizer comprises oxygen that permeates the second electrode.

10. An electrochemical cell according to claim 9, wherein the second electrode comprises a barrier membrane on the outer surface thereof that is gas permeable and liquid impermeable so as to permit permeation of the oxidizer via the outer surface of the second electrode and prevent the electrolyte from flowing through the outer surface of the second electrode.

11. An electrochemical cell according to claim 1, wherein a catalytic material of the second electrode comprises a material selected from the group consisting of manganese oxide, nickel, pyrolized cobalt, activated carbon, and platinum.

12. An electrochemical cell according to claim 1, wherein the plurality of return channels are disposed adjacent the permeable electrode body and opposite the gap from the second electrode.

13. An electrochemical cell according to claim 12, wherein the plurality of return channels are arranged peripherally around the permeable electrode body.

14. An electrochemical cell according to claim 13, wherein the permeable electrode body is supported by an electrode holder, and the electrode holder also has the plurality of return channels provided therethrough.

15. An electrochemical cell according to claim 14, wherein the electrode holder includes a cavity in which the permeable electrode body is received, and wherein the cavity and the return channels are parallel to one another.

16. An electrochemical cell system comprising:

an electrolyte;

oxidizable solid fuel; and

a plurality of electrochemical cells arranged in an array;

each electrochemical cell comprising;

(i) a permeable electrode body provided along a flow path for receiving a flow comprising at least the electrolyte, the permeable electrode body being configured to permit the electrolyte to flow therethrough, the permeable electrode body also being configured to collect the solid fuel thereon from the electrolyte flowing therethrough so as to comprise a first electrode for oxidizing the fuel to generate electrons for conduction by the first electrode;

(ii) a second electrode for receiving electrons and reducing an oxidizer;

(iii) the first electrode and the second electrode being spaced apart to define a gap therebetween for receiving the flow from the permeable electrode body; and

(iv) a plurality of return channels communicated directly to the gap and disposed radially outward from the permeable electrode body; and

one or more flow generators configured to generate the flow in each electrochemical cell comprising at least the electrolyte (i) through the permeable electrode body and towards the second electrode across the gap to transport at least the electrolyte and the oxidized fuel ions away from the permeable electrode body and towards the second electrode, and (ii) then through the plurality of return channels to transport at least the electrolyte and any by-product formed in the gap by the reaction of the oxidized fuel ions and the reduced oxidizer ions away from the gap without flowing through the second electrode.

17. An electrochemical cell system according to claim 16, wherein the solid fuel is selected from the group consisting of iron, zinc, magnesium, aluminum, and lithium.

18. An electrochemical cell system according to claim 17, wherein the solid fuel is zinc.

19. An electrochemical cell according to claim 16, wherein the electrolyte comprises at least one aqueous solution selected from the group consisting of sulfuric acid, phosphoric acid, triflic acid, nitric acid, potassium hydroxide, sodium hydroxide, sodium chloride, potassium nitrate, and lithium chloride.

20. An electrochemical cell system according to claim 19, wherein the electrolyte comprises potassium hydroxide.

21. An electrochemical cell system according to claim 16, wherein the oxidizable solid fuel comprises solid fuel particulates, and wherein the permeable electrode body of each electrochemical cell is a filter body configured to filter the solid fuel particulates from the electrolyte for collecting the fuel thereon.

22. An electrochemical cell system according to claim 21, wherein the filter body comprises a carbon filter, a brass screen, or a bronze screen.

23. An electrochemical cell system according to claim 16, wherein the second electrode of each electrochemical cell is a gas permeable electrode having an outer surface exposed to ambient air such that the oxidizer comprises oxygen that permeates the second electrode.

24. An electrochemical cell system according to claim 16, wherein a catalytic material of each second electrode comprises a material selected from the group consisting of manganese oxide, nickel, pyrolized cobalt, activated carbon, and platinum.

25. An electrochemical cell system according to claim 24, wherein each second electrode comprises a barrier membrane on the outer surface thereof that is gas permeable and liquid impermeable so as to permit permeation of the oxidizer via the outer surface of the second electrode and prevent the electrolyte from flowing through the outer surface of the second electrode.

26. An electrochemical cell system according to claim 16, wherein in each electrochemical cell, the plurality of return channels are disposed adjacent the permeable electrode body and opposite the gap from the second electrode.

27. An electrochemical cell system according to claim 26, wherein in each electrochemical cell, the plurality of return channels are arranged peripherally around the permeable electrode body.

28. An electrochemical cell system according to claim 27, wherein in each electrochemical cell, the permeable electrode body is supported by an electrode holder, and the electrode holder also has the plurality of return channels provided therethrough.

29. An electrochemical cell system according to claim 28, wherein each electrode holder includes a cavity in which the permeable electrode body is received, and wherein the cavity and the return channels are parallel to one another.

30. An electrochemical cell system according to claim 16, wherein the second electrodes of the electrochemical cells are provided by a common second electrode.

31. An electrochemical cell system according to claim 16, further comprising walls separating the gaps of adjacent electrochemical cells from one another.

32. An electrochemical cell system according to claim 16, wherein the one or more flow generators is a single flow generator coupled to each of the electrochemical cells.

33. A method for generating electrical current using an electrochemical cell, the method comprising:

flowing an electrolyte comprising an oxidizable solid fuel or ions thereof through a permeable electrode body provided along a flow path, the permeable electrode body permitting the electrolyte to flow therethrough and collecting the solid fuel thereon from the electrolyte so as to comprise a first electrode, the first electrode being spaced apart from a second electrode to define a gap therebetween;

oxidizing the oxidizable solid fuel at the first electrode and reducing an oxidizer at the second electrode whereby electrons are generated for conduction from the first electrode to the second electrode via a load, and the oxidized fuel ions and reduced oxidizer ions react to form a by-product; and

flowing the electrolyte (i) through the permeable electrode body and towards the second electrode across the gap to transport at least the electrolyte and the oxidized fuel ions away from the permeable electrode body and towards the second electrode, and (ii) then through a plurality of return channels disposed radially outward from the permeable electrode body to transport at least the electrolyte and the by-product formed in the gap by the reaction of the oxidized fuel ions and the reduced oxidizer ions away from the gap without flowing through the second electrode.

34. A method according to claim 33, wherein the solid fuel is selected from the group consisting of iron, zinc, magnesium, aluminum, and lithium.

35. A method according to claim 34, wherein the solid fuel is zinc.

36. A method according to claim 35, wherein the electrolyte comprises at least one aqueous solution selected from the group consisting of sulfuric acid, phosphoric acid, triflic acid, nitric acid, potassium hydroxide, sodium hydroxide, sodium chloride, potassium nitrate, and lithium chloride.

37. A method according to claim 36, wherein the electrolyte comprises potassium hydroxide.

38. A method according to claim 33, wherein the second electrode is a gas permeable electrode having an outer surface exposed to ambient air such that the oxidizer comprises oxygen that permeates the second electrode.

39. A method according to claim 38, wherein the second electrode comprises a barrier membrane on the outer surface thereof that is gas permeable and liquid impermeable so as to permit permeation of the oxidizer via the outer surface of the second electrode and prevent the electrolyte from flowing through the outer surface of the second electrode.

40. A method according to claim 33, wherein the plurality of return channels are disposed adjacent the permeable electrode body and opposite the gap from the second electrode such that the flow flowing towards and into the plurality of return channels is flowing away from the second electrode.

41. A method according to claim 40, wherein the plurality of return channels are arranged peripherally around the permeable electrode body such that the portion of the flow leaving the permeable electrode body and portion of the flow towards the plurality of return channels run counter to one another in an overlapping manner.

42. A method according to claim 33, wherein the collecting comprises filtering solid fuel particulates out of the electrolyte with the permeable electrode body.

43. A method according to claim 42, wherein said flowing the electrolyte and the oxidizable solid fuel through the permeable electrode body to perform said collecting of solid fuel by filtering and flowing the electrolyte through the permeable electrode body and across the gap to perform said transporting of oxidized fuel ions are performed simultaneously by the same flowing of electrolyte.

44. A method according to claim 33, wherein the collecting comprises electrodepositing the solid fuel onto the permeable electrode body.

45. A method according to claim 44, wherein said flowing the electrolyte and the oxidizable solid fuel through the permeable electrode body to perform said collecting of solid fuel by electrodepositing and flowing the electrolyte through the permeable electrode body and across the gap to perform said transporting of oxidized fuel ions are performed at different times, wherein said permeable electrode body functions as a cathode during the electrodepositing to reduce the solid fuel for collection thereon.

46. An electrochemical cell for use with an electrolyte and reactants comprising a fuel and an oxidizer, the electrochemical cell comprising:

electrodes comprising;

(i) an anode for oxidizing the fuel into at least oxidized fuel ions and electrons, and (ii) a cathode for accepting electrons and reducing the oxidizer into at least reduced oxidizer ions;

a first of the electrodes being provided along a flow path for receiving a flow comprising the electrolyte and a corresponding first of the reactants,

a second electrode for receiving a corresponding second of the reactants, the first and second electrodes being spaced apart to define a gap therebetween for receiving the flow from the first electrode;

a plurality of return channels communicated directly to the gap and disposed adjacent to and radially outward from the first electrode and opposite the gap from the second electrode; and

a flow generator configured to generate a flow comprising at least the electrolyte (i) from the first electrode and towards the second electrode across the gap to transport at least the electrolyte and the ions formed from oxidation or reduction of the first reactant at the first electrode away from the first electrode and towards the second electrode, and (ii) then through the plurality of return channels to transport at least the electrolyte and any by-product formed by the reaction of the oxidized fuel ions and the reduced oxidizer ions away from the gap.

47. An electrochemical cell according to claim 46, wherein the plurality of return channels are arranged such that the portion of the flow leaving the first electrode and the portion of the flow towards the plurality of return channels run counter to one another in an overlapping manner.

48. An electrochemical cell according to claim 47, wherein the plurality of return channels are arranged peripherally around the first electrode.

49. An electrochemical cell according to claim 48, wherein the first electrode is supported by a holder, and the holder also has the plurality of return channels provided therethrough.

50. An electrochemical cell according to claim 49, wherein the holder includes a cavity in which the first electrode is received, and wherein the cavity and the return channels are parallel to one another.

51. An electrochemical cell according to claim 50, wherein the return channels are arranged with the first electrode being aligned with a center of a geometry defined by the return channels.

52. An electrochemical cell according to claim 46, wherein the first electrode is the anode, and the first reactant is the fuel, and wherein the second electrode is the cathode and the second reactant is the oxidizer.