IMMERSIBLE GASEOUS OXIDANT CATHODE FOR ELECTROCHEMICAL CELL SYSTEM

• US 20130115523A1
• Filed: 06/25/2012
• Published: 05/09/2013
• Est. Priority Date: 11/04/2011
• Status: Active Grant

• Current Assignee: Form Energy, Inc.
• Original Assignee: Fluidic, Inc.
• Inventors: FRIESEN, Cody A., KRISHNAN, Ramkumar, FRIESEN, Grant, GOODFELLOW, Andrew, MIHALKA, Michael
• Granted Patent: US 9,444,105 B2
• Time in Patent Office: Days
• US Class Current: 429/402
• CPC Class Codes: H01M 12/065 with plate-like electrodes or stacks of plate-like electrodes
• 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 4/86 Inert electrodes with catalytic activity, e.g. for fuel cells
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

An electrochemical cell system is configured to utilize an oxidant reduction electrode module containing an oxidant reduction electrode mounted to a housing to form a gaseous oxidant space therein that is immersed into the ionically conductive medium. A fuel electrode is spaced from the oxidant reduction electrode, such that the ionically conductive medium may conduct ions between the fuel and oxidant reduction electrodes to support electrochemical reactions at the fuel and oxidant reduction electrodes. A gaseous oxidant channel extending through the gaseous oxidant space provides a supply of oxidant to the oxidant reduction electrode, such that the fuel electrode and the oxidant reduction electrode are configured to, during discharge, oxidize the metal fuel at the fuel electrode and reduce the oxidant at the oxidant reduction electrode, to generate a discharge potential difference therebetween for application to a load.

Claims

1. An oxidant reduction electrode module for immersion into an ionically conductive medium of an electrochemical cell, the oxidant reduction electrode module comprising:

a housing configured to define a gaseous oxidant receiving space therein;

an oxidant reduction electrode having an oxidant facing side and an ionically conductive medium facing side, the oxidant reduction electrode mounted to said housing such that the oxidant reduction electrode defines a boundary wall for the gaseous oxidant receiving space, with the oxidant facing side facing inwardly to the gaseous oxidant receiving space and the ionically conductive medium facing side facing outwardly for exposure to the ionically conductive medium;

a gaseous oxidant inlet and a gaseous oxidant outlet coupled by a gaseous oxidant channel extending through the gaseous oxidant receiving space; and

one or more support members positioned within the gaseous oxidant receiving space, configured to prevent deformation of the oxidant reduction electrode into the gaseous oxidant receiving space when the oxidant reduction electrode is immersed into the ionically conductive medium, and direct a flow of gaseous oxidant within the gaseous oxidant channel from the gaseous oxidant inlet to the gaseous oxidant outlet; and

wherein an oxidant is allowed into the gaseous oxidant receiving space via the gaseous oxidant inlet, the oxidant reduction electrode being configured to absorb the gaseous oxidant via the oxidant facing side and reduce the gaseous oxidant during discharge of the electrochemical cell.

2. The oxidant reduction electrode of claim 1, wherein the housing is of a singular molded construction, and configured such that only a single seal, being formed between the housing and the oxidant reduction electrode, is to be immersed into the ionically conductive medium.

3. The oxidant reduction electrode module of claim 1, wherein the oxidant reduction electrode is sealed to the housing by a sealant that is impermeable to the ionically conductive medium.

4. The oxidant reduction electrode module of claim 1, wherein the oxidant reduction electrode comprises polytetrafluoroethylene.

5. The oxidant reduction electrode module of claim 1, wherein the one or more support members are formed integral to the housing.

6. The oxidant reduction electrode module of claim 1, wherein the one or more support members comprise baffles for the gaseous oxidant.

7. The oxidant reduction electrode of claim 1, wherein portions of the one or more support members spaced adjacent to one another, separated by a spacing defining a portion of the gaseous oxidant channel.

8. The oxidant reduction electrode of claim 7, wherein the spacing is approximately between 1-50 mm.

9. The oxidant reduction electrode of claim 8, wherein the spacing is approximately 20 mm.

10. The oxidant reduction electrode of claim 8, wherein the spacing is approximately 10 mm.

11. The oxidant reduction electrode module of claim 1, wherein the gaseous oxidant allowed into the gaseous oxidant receiving space via the gaseous oxidant inlet is pressurized to maintain a positive pressure in the gaseous oxidant receiving space.

12. The oxidant reduction electrode module of claim 1, installed into an electrochemical cell housing for an electrochemical cell comprising:

(i) the ionically conductive medium and (ii) a fuel electrode comprising a metal fuel and positioned in the housing such that the metal fuel is exposed to the ionically conductive medium for electrochemically oxidizing the metal fuel, such that the oxidant reduction electrode is spaced from the fuel electrode;

wherein the ionically conductive medium conducts ions between the fuel electrode and the ionically conductive medium facing side of the oxidant reduction electrode to support the electrochemical reactions at the fuel and oxidant reduction electrodes.

13. The oxidant reduction electrode module installed into the electrochemical cell housing of claim 12, wherein the ionically conductive medium is a liquid.

14. An assembly comprising the oxidant reduction electrode module of claim 1 coupled to a fuel electrode module containing a fuel electrode, the assembly configured to space the oxidant reduction electrode from the fuel electrode, so that, when immersed into the ionically conductive medium, the ionically conductive medium facing side of the oxidant reduction electrode and a metal fuel of the fuel electrode are exposed to the ionically conductive medium for electrochemically oxidizing the metal fuel, wherein the ionically conductive medium conducts ions between the fuel electrode and the ionically conductive medium facing side of the oxidant reduction electrode to support the electrochemical reactions between the oxidant reduction electrode and the fuel electrode.

15. The assembly of claim 14, further comprising a cell cover containing a cell cover gaseous oxidant inlet configured to couple to the gaseous oxidant inlet of the oxidant reduction electrode module, so as to permit the flow of gaseous oxidant through the cell cover to the oxidant reduction electrode.

16. The assembly of claim 14, further comprising a second oxidant reduction electrode module comprising an associated oxidant reduction electrode, the second oxidant reduction electrode module positioned opposite the oxidant reduction electrode module, wherein the oxidant reduction electrode of the oxidant reduction electrode module faces the oxidant reduction electrode of the second oxidant reduction electrode module, with the fuel electrode positioned between the oxidant reduction electrode of the oxidant reduction electrode module and the oxidant reduction electrode of the second oxidant reduction electrode module.

17. The assembly of claim 16, further comprising a second fuel electrode positioned between the oxidant reduction electrode of the oxidant reduction electrode module and the oxidant reduction electrode of the second oxidant reduction electrode module, the fuel electrode being associated with the oxidant reduction electrode of the oxidant reduction electrode module, and the second fuel electrode being associated with the oxidant reduction electrode of the second oxidant reduction electrode module.

18. An electrochemical cell system comprising:

a chamber configured to contain a quantity of ionically conductive medium therein;

one or more fuel electrodes, each comprising a metal fuel and configured to be contacted by the ionically conductive medium; and

one or more oxidant reduction electrode modules immersed into the ionically conductive medium, each oxidant reduction electrode module comprising;

a housing configured to define a gaseous oxidant space therein;

an oxidant reduction electrode having an oxidant facing side and an ionically conductive medium facing side, the oxidant reduction electrode mounted to said housing such that the oxidant reduction electrode defines a boundary wall for the gaseous oxidant space, with the oxidant facing side facing inwardly to the gaseous oxidant space and the ionically conductive medium facing side facing outwardly for exposure to the ionically conductive medium;

a gaseous oxidant inlet and a gaseous oxidant outlet coupled by a gaseous oxidant channel extending through the gaseous oxidant space, configured to allow a flow of gaseous oxidant to the oxidant facing side of the oxidant reduction electrodes; and

one or more support members positioned within the gaseous oxidant space, configured to prevent deformation of the oxidant reduction electrode into the gaseous oxidant space when the oxidant reduction electrode is immersed into the ionically conductive medium, and direct the flow of gaseous oxidant within the gaseous oxidant channel from the gaseous oxidant inlet to the gaseous oxidant outlet; and

wherein one or more electrochemical cells are defined by each fuel electrode and at least one associated oxidant reduction electrode, each of the one or more electrochemical cells being configured to, during discharge, oxidize the metal fuel at the fuel electrode and reduce the gaseous oxidant at the at least one associated oxidant reduction electrode to generate a discharge potential difference therebetween for application to a load.

19. The electrochemical cell system of claim 18, wherein each fuel electrode is configured to be mounted to an associated one of the one or more oxidant reduction electrode modules, such that the fuel electrode and the associated oxidant reduction electrode module are jointly immersed in the ionically conductive medium.

20. The electrochemical cell system of claim 18, wherein each electrochemical cell further comprises a charging electrode selected from the group consisting of (a) the oxidant reduction electrode, and (b) a separate charging electrode spaced from the fuel and oxidant reduction electrodes of each electrochemical cell.

21. The electrochemical cell system of claim 18, wherein each fuel electrode and the charging electrode are configured to, during re-charge, reduce a reducible species of the metal fuel to electrodeposit the metal fuel on the fuel electrode and oxidize an oxidizable species of the oxidant by application of a re-charge potential difference therebetween from a power source.

22. The electrochemical cell system of claim 21, wherein each fuel electrode comprises a series of permeable electrode bodies arranged in spaced apart relation;

wherein the spaced apart relation of the permeable electrode bodies enables the re-charge potential difference to be applied between the charging electrode and at least one of the permeable electrode bodies, with the charging electrode functioning as the anode and the at least one permeable electrode body functioning as the cathode, such that the reducible fuel species are reduced and electrodeposited as the metal fuel in oxidizable form on the at least one permeable electrode body, wherein the electrodeposition causes growth of the metal fuel among the permeable electrode bodies such that the electrodeposited metal fuel establishes an electrical connection between the permeable electrode bodies.

23. The electrochemical cell system of claim 21, wherein the reducible species of the metal fuel comprises ions of zinc, iron, aluminum, magnesium, or lithium, and wherein the metal fuel is zinc, iron, aluminum, magnesium, or lithium.

24. The electrochemical cell system of claim 18, wherein the ionically conductive medium comprises an aqueous electrolyte solution.

25. The electrochemical cell system of claim 24, wherein the aqueous electrolyte solution comprises sulfuric acid, phosphoric acid, triflic acid, nitric acid, potassium hydroxide, sodium hydroxide, sodium chloride, potassium nitrate, or lithium chloride.

26. The electrochemical cell system of claim 18, further comprising a gaseous oxidant pump configured to pump an amount of the gaseous oxidant into the gaseous oxidant channel.

27. The electrochemical cell system of claim 18, wherein the housing of the oxidant reduction electrode module is of a singular molded construction, and configured such that only a single seal, being formed between the housing and the oxidant reduction electrode, is to be immersed into the ionically conductive medium.

28. The electrochemical cell system of claim 18, wherein the oxidant reduction electrode is sealed to the housing of the oxidant reduction electrode module by a sealant that is impermeable to the ionically conductive medium.

29. The electrochemical cell system of claim 18, wherein the oxidant reduction electrode comprises polytetrafluoroethylene.

30. The electrochemical cell system of claim 18, wherein the one or more support members are formed integral to the housing.

31. The electrochemical cell system of claim 18, wherein the one or more support members comprise baffles for the gaseous oxidant.

32. The electrochemical cell system of claim 31, wherein portions of the one or more support members spaced adjacent to one another, separated by a spacing defining a portion of the gaseous oxidant channel.

33. The electrochemical cell system of claim 32, wherein the spacing is approximately between 1-50 mm.

34. The electrochemical cell system of claim 33, wherein the spacing is approximately 20 mm.

35. The electrochemical cell system of claim 33, wherein the spacing is approximately 10 mm.

36. The electrochemical cell system of claim 18, wherein the gaseous oxidant allowed into the gaseous oxidant space of the oxidant reduction electrode module via the gaseous oxidant channel is pressurized to maintain a positive pressure in the gaseous oxidant space.

37. The electrochemical cell system of claim 18, wherein the one or more oxidant reduction electrode modules comprises two oxidant reduction electrode modules configured to surround the one or more fuel electrodes, the two oxidant reduction electrode modules positioned opposite each other such that the oxidant reduction electrode of each of the two oxidant reduction electrode modules face one another, and surround the one or more fuel electrodes.

38. The electrochemical cell system of claim 37, wherein the one or more fuel electrodes comprises a single fuel electrode, common to each oxidant reduction electrode of the two oxidant reduction electrode modules.

39. A method of assembling an oxidant reduction electrode module configured for immersion into an ionically conductive medium of an electrochemical cell, the method comprising:

providing a housing coupled to a gaseous oxidant inlet and a gaseous oxidant outlet, wherein an interior of the housing defines a gaseous oxidant space;

providing one or more support members within the gaseous oxidant space, configured to form a gaseous oxidant channel to direct a flow of gaseous oxidant between the gaseous oxidant inlet and the gaseous oxidant outlet; and

sealing an oxidant reduction electrode to the housing, such that an oxidant facing side of the oxidant reduction electrode faces inwardly into the gaseous oxidant space and defines a boundary wall for the gaseous oxidant space, and an ionically conductive medium facing side of the oxidant reduction electrode faces outwardly for exposure to the ionically conductive medium when the oxidant reduction electrode module is immersed therein;

wherein, when immersed in the ionically conductive medium, the assembly of the housing and the oxidant reduction electrode prevents flow of the ionically conductive medium into the gaseous oxidant space;

wherein the one or more support members are configured to prevent deformation of the oxidant reduction electrode into the gaseous oxidant space when the oxidant reduction electrode is immersed into the ionically conductive medium; and

wherein the gaseous oxidant inlet permits the flow of gaseous oxidant into the gaseous oxidant space.

40. A method of assembling an electrochemical cell comprising:

providing a chamber configured to contain a quantity of ionically conductive medium therein;

immersing, within the quantity of ionically conductive medium;

(i) an immersible oxidant reduction electrode module configured to maintain a gaseous oxidant space bounded by a housing and an oxidant facing side of an oxidant reduction electrode, the gaseous oxidant space coupled to a gaseous oxidant inlet and a gaseous oxidant outlet; and

(ii) a fuel electrode, each comprising a metal fuel and configured to be contacted by the ionically conductive medium; and

receiving gaseous oxidant into the gaseous oxidant space via the gaseous oxidant inlet;

wherein one or more support members are provided in the gaseous oxidant space, configured to prevent deformation of the oxidant reduction electrode into the gaseous oxidant receiving space when the oxidant reduction electrode is immersed into the ionically conductive medium, while defining a gaseous oxidant channel configured to direct a flow of gaseous oxidant between the gaseous oxidant inlet and the gaseous oxidant outlet;

wherein an ionically conductive medium facing side of the oxidant reduction electrode faces the fuel electrode and is exposed to the ionically conductive medium, such that the ionically conductive medium may conduct ions between the fuel and oxidant reduction electrodes to support electrochemical reactions at the fuel and oxidant reduction electrodes; and

wherein the fuel electrode and oxidant reduction electrode are configured to, during discharge, oxidize the metal fuel at the fuel electrode and reduce the gaseous oxidant at the oxidant reduction electrode to generate a discharge potential difference therebetween for application to a load.