Thin electrode supported on electronically conductive sheet and process of manufacture

• US 4,824,746 A
• Filed: 03/11/1988
• Issued: 04/25/1989
• Est. Priority Date: 03/11/1987
• Status: Expired due to Term

• Current Assignee: Hydro-Quebec (Province of Québec)
• Original Assignee: Hydro-Quebec (Province of Québec)
• Inventors: Gauthier, Michel, Robitaille, Michel, Belanger, Andre
• Primary Examiner(s): Skapars, Anthony
• Application Number:
  US07/166,980
• Time in Patent Office: 410 Days
• Field of Search: 427/177, 427/115, 427/178, 427/211, 427/319, 427/356, 427/366, 427/428, 427/431, 427/432, 427/434.2, 427/357, 29/623.5, 429/218, 429/209
• US Class Current: 429/231.6
• CPC Class Codes: H01M 2004/027 Negative electrodes
• CPC Class Codes: H01M 2300/0082 Organic polymers
• CPC Class Codes: H01M 4/04 Processes of manufacture in general
• CPC Class Codes: H01M 4/0402 Methods of deposition of the material
• CPC Class Codes: H01M 4/0404 by coating on electrode collectors
• CPC Class Codes: H01M 4/043 involving compressing or compaction
• CPC Class Codes: H01M 4/0435 Rolling or calendering
• CPC Class Codes: H01M 4/0483 by methods including the handling of a melt H01M4/0438, take precedence
• CPC Class Codes: H01M 4/38 of elements or alloys
• CPC Class Codes: H01M 4/405 Alloys based on lithium
• CPC Class Codes: H01M 4/661 Metal or alloys, e.g. alloy coatings H01M4/669 take precedence
• CPC Class Codes: H01M 4/662 Alloys collectors of lead alloys H01M4/685
• CPC Class Codes: H01M 4/666 in the form of mixed materials H01M4/668 takes precedence
• CPC Class Codes: H01M 4/667 in the form of layers, e.g. coatings
• CPC Class Codes: H01M 4/668 Composites of electroconductive material and synthetic resins
• CPC Class Codes: H01M 4/806 Nonwoven fibrous fabric containing only fibres
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y10T 29/49115 including coating or impregnating

Abstract

Process of manufacturing thin electrodes, supported on an electronically conductive sheet, the electrodes being made from an element selected from lithium, lithium alloy, or doped lithium, whose melting point does not differ from the melting point of lithium by ±50° C. and whose thickness is constant, from a roller of the sheet and a source of the element. According to the invention, there is provided a bath of the element in molten state, the sheet is continuously unrolled, a constant quantity of the molten element is continuously applied on one of the two faces of the sheet, so as to produce a film on the sheet, whose thickness is constant and between about 0.1 and about 40μ and whose surface is homogeneous and uniform. The process is carried out in such a manner that the molten element is prevented from solidifying while in contact with the sheet, and the solidification of the element on the sheet takes place after formation of the film on the sheet. Electrode made of a sheet coated with a layer of lithium whose thickness is 0.1 to 40μ.

Claims

1. Process for manufacturing thin electrodes supported on an electronically conductive sheet, said electrodes being made from an element selected from the group consisting of lithium, lithium alloy and doped lithium, whose melting point does not differ from the melting point of lithium by ±

50°

C., the thickness of said element being constant, from a roll of said sheet and a source of said element, which comprises providing a bath of said element in molten state and keeping said bath under an inert atmosphere, continuously unwinding said sheet, continuously applying on at least one of the two faces of said sheet, a constant quantity of said element in molten state, so as to produce a film on said sheet whose thickness is constant and between about 0.1 and about of 40μ and

whose surface is homogeneous and uniform, preventing the element in molten state from immediately solidifying while in contact with said sheet, and causing a controlled solidification of said element on said sheet after said film has been formed thereon.

2. Process according to claim 1, wherein said sheet is made of a material selected from the group consisting of a metal, an alloy, a metallized fiberglass, a loaded plastic and a metallized plastic.

3. Process according to claim 2, wherein the sheet is made of a metal selected from the group consisting of copper, nickel, iron and molybdenum.

4. Process according to claim 2, wherein the sheet comprises an alloy of nickel, copper or iron.

5. Process according to claim 4, wherein the sheet is made of brass, bronze, steel or monel.

6. Process according to claim 2, wherein the sheet is made of nickel.

7. Process according to claim 6, wherein the element is metallic lithium.

8. Process according to claim 1, wherein the element is an alloy of lithium.

9. Process according to claim 1, wherein the lithium is alloyed or doped with antimony, bismuth, boron, tin, silicon, magnesium.

10. Process according to claim 7, which comprises keeping the bath at a temperature varying between the melting point of lithium and about 400°

C.

11. Process according to claim 10, which comprises unwinding the sheet above the bath of molten lithium.

12. Process according to claim 11, which comprises continuously circulating a molten lithium applicator in said bath, and applying said applicator on said face of the sheet of nickel.

13. Process according to claim 12, wherein said applicator comprises a roller whose axis is parallel to the surface of molten lithium, the base of the roller being immersed in the molten lithium while the upper portion is in contact with said face, the surface of the roller comprises asperities allowing the roller to be coated with molten lithium so as to uniformly transfer the latter on said face of the sheet of nickel.

14. Process according to claim 13, wherein the asperities consist of regular geometrical patterns constituting cavities regularly distributed across the roller surface, said cavities collecting the molten material and transferring same on the metallic sheet.

15. Process according to claim 14, wherein the cavities are gauged as a function of the thickness of the layer of pure lithium, lithium alloy or doped lithium.

16. Process according to claim 15, which comprises unrolling the sheet at a speed between 0.5 and 100 cm/s.

17. Process according to claim 15, which comprises heating the roller in order to prevent the molten lithium from immediately solidifying before being applied against said face of the sheet.

18. Process according to claim 1, which comprises thermally treating said sheet before and after having applied the element in molten state against said face.

19. Process according to claim 15, wherein after having coated the metallic sheet with molten lithium, said face is treated with a scraper thereby reducing the thickness of lithium applied and optionally removing surface imperfections left by the roller.

20. Process according to claim 15, which comprises maintaining the lithium bath as well as the sheet, in the vicinity of said lithium bath, under an inert atmosphere containing neither oxygen nor water vapor.

21. Process according to claim 13, which comprises providing a scraper for removing any excess molten material from the surface of the roller before the latter is applied to the face of the metallic sheet to be coated.

22. Thin supported electrode which comprises an electronically conductive sheet, at least one face of which is at least partially covered with a layer of an element selected from the group consisting of lithium, lithium alloy and doped lithium, the melting point of said element being close to that of lithium to ±

50°

C., the layer of said element having a uniform thickness varying between about 0.1μ and

about 40μ

, the surface of said layer being substantially free of asperities and cannot be removed from the sheet by means of a knife, whenever produced by the process according to claim 1.

23. Electrode according to claim 22, wherein the sheet is made of a material selected from the group consisting of a metal, an alloy, a metallized fiberglass, a loaded plastic and metallized plastic.

24. Electrode according to claim 23, wherein the sheet comprises a metal selected from the group consisting of copper, nickel, iron and molybdenum.

25. Electrode according to claim 23, wherein the sheet comprises an alloy based on nickel, copper or iron.

26. Electrode according to claim 25, wherein the sheet is made of brass, bronze, steel or monel.

27. Electrode according to claim 23, wherein the sheet is made of nickel.

28. Electrode according to claim 27, wherein the element is metallic lithium.

29. Electrode according to claim 22, wherein the element is selected from the alloys of lithium.

30. Electrode according to claim 29, wherein the lithium is alloyed with antimony, bismuth, boron, tin, silicon, magnesium.

31. Electrochemical generator comprising an anode, a cathode as well as an electrolyte wherein the anode is as defined in any one of claims 22, 23 or 24.

32. Electrochemical generator comprising an anode, a cathode as well as an electrolyte wherein the anode is as defined in any one of claims 25, 26 or 27.

33. Electrochemical generator comprising an anode, a cathode as well as an electrolyte wherein the anode is as defined in any one of claims 29 or 30.