Electrolyte activatable lithium-ion rechargeable battery cell

• US 5,460,904 A
• Filed: 11/30/1993
• Issued: 10/24/1995
• Est. Priority Date: 08/23/1993
• Status: Expired due to Term

• Current Assignee: Valence Technology Incorporated (Lithium Werks B.V.)
• Original Assignee: Bell Communications Research, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Gozdz, Antoni S., Tarascon, Jean-Marie, Warren, Paul C.
• Primary Examiner(s): Maples, John S.
• Application Number:
  US08/160,018
• Time in Patent Office: 693 Days
• Field of Search: 429/254, 429/162, 429/127, 429/192, 429/185, 429/217
• US Class Current: 429/316
• CPC Class Codes: C08J 2327/16 Homopolymers or copolymers of vinylidene fluoride
• CPC Class Codes: C08J 9/28 by elimination of a liquid phase from a macromolecular composition or article, e.g. drying of coagulum
• CPC Class Codes: H01M 10/0431 Cells with wound or folded electrodes H01M10/045 takes precedence
• CPC Class Codes: H01M 10/05 Accumulators with non-aqueous electrolyte H01M10/39 takes precedence
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/0565 Polymeric materials, e.g. gel-type or solid-type
• CPC Class Codes: H01M 2300/0085 Immobilising or gelification of electrolyte
• CPC Class Codes: H01M 50/426 Fluorocarbon polymers
• CPC Class Codes: H01M 50/489 Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
• CPC Class Codes: H01M 50/497 Ionic conductivity
• CPC Class Codes: H01M 6/181 with polymeric electrolytes
• CPC Class Codes: H01M 6/30 Deferred-action cells
• CPC Class Codes: H01M 6/32 activated through external addition of electrolyte or of electrolyte components
• CPC Class Codes: H01M 6/42 Grouping of primary cells into batteries H01M6/40 takes precedence
• CPC Class Codes: H01M 6/46 of flat cells
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y10T 29/4911 including sealing
• CPC Class Codes: Y10T 29/49114 including adhesively bonding

Abstract

Li-ion rechargeable battery cell electrode and electrolyte/separator elements formulated as layers of plasticized polymeric matrix compositions are laminated to form a unitary battery cell structure. The structure may be stored indefinitely, since it is essentially devoid of electrolyte solution which typically comprises a moisture-sensitive lithium salt. Prior to the battery'"'"'s being put into service, the plasticizer of the polymeric composition is removed by leaching with a selective solvent and is replaced with a lithium salt electrolyte solution by simple imbibition. The battery thus activated may then be charged and recharged in the usual manner.

Claims

1. A rechargeable battery structure comprising a positive electrode element, a negative electrode element, and a separator element disposed therebetween characterized in that

a) each of said elements comprises a flexible, self-supporting, polymeric matrix film composition substantially devoid of electrolytic salt;

b) each said element is bonded to contiguous elements at its respective interfaces to form a unitary flexible laminate structure; and

c) said separator element film is substantially devoid of pores and comprises a composition initially comprising a polymeric material and 20 to 70% by weight of a compatible plasticizer therefor and from which composition at least a portion of said plasticizer has been removed, said separator element thereby being in a preconditioned state conducive to absorption of electrolytic solution.

2. A rechargeable battery structure according to claim 1 wherein each said element is heat-fused at its respective interfaces.

14. A rechargeable battery structure according to claim 1 wherein the removed plasticizer has been replaced with a battery electrolyte solution.

3. A rechargeable battery structure comprising a positive electrode element, a negative electrode element, and a separator element disposed therebetween characterized in that

a) each of said elements comprises a flexible, self-supporting, polymeric matrix film composition;

b) each said element is bonded to contiguous elements at its respective interfaces to form a unitary flexible laminate structure; and

c) said separator element composition comprises a copolymer of vinylidene fluoride with 8 to 25% by weight hexafluoropropylene and has homogeneously distributed therein 20 to 70% by weight of a compatible organic plasticizer for said copolymer.

4. A rechargeable battery structure according to claim 3 wherein said separator element composition comprises 10 to 30% by weight based on said copolymer of an inorganic filler selected from fumed alumina and silanized fumed silica.

5. A rechargeable battery structure according to claim 3 wherein said positive electrode element composition comprises a lithium intercalation compound homogeneously distributed in a matrix of said separator element composition.

6. A rechargeable battery structure according to claim 5 wherein said lithium compound has a nominal formula selected from LiMn₂ O₄, LiCoO₂, and LiNiO₂.

7. A rechargeable battery structure according to claim 6 wherein said lithium compound has the formula Li_1+x Mn₂ O₄ where 0≦

x≦

1.

8. A rechargeable battery structure according to claim 5 wherein said negative electrode element composition comprises a compound selected from the group consisting of carbon intercalation compounds and low-voltage lithium insertion compounds homogeneously distributed in a matrix of said separator element composition.

9. A rechargeable battery structure according to claim 8 wherein said negative electrode element composition compound is selected from the group consisting of petroleum coke and graphite.

10. A rechargeable battery structure according to claim 9 wherein said plasticizer is selected from the group consisting of ethylene carbonate, propylene carbonate, dibutyl phthalate, dimethyl phthalate, diethyl phthalate, tris butoxyethyl phosphate, and mixtures thereof.

11. A rechargeable battery structure comprising a laminate structure according to claim 3 from which at least a portion of said plasticizer has been extracted.

12. A rechargeable battery structure comprising a laminate structure according to claim 3 in which at least a portion of said plasticizer has been replaced with a lithium battery electrolyte solution.

13. A rechargeable battery structure according to claim 12 wherein said electrolyte solution comprises a 0.5 to 2M solution of:

a) a lithium salt selected from the group consisting of LiPF₆, LiClO₄, LiN(CF₃ SO₂)₂, LiBF₄, LiCF₃ SO₃, LiSbF₆, and mixtures thereof;

in

b) an organic solvent selected from the group consisting of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethoxyethane, diethyl carbonate, dimethoxyethane, dipropyl carbonate, and mixtures thereof.

15. A rechargeable battery structure comprising, in sequence, a positive current collector element, a positive electrode element, a separator element, a negative electrode element, and a negative current collector element characterized in that

a) each of said collector elements comprises a flexible electrically-conductive foil,

b) each of the others of said elements comprises a flexible, self-supporting, polymeric matrix film composition substantially devoid of electrolytic salt;

c) each said element is bonded to contiguous elements at its respective interfaces to form a unitary flexible laminate structure; and

d) said separator element film is substantially devoid of pores and comprises a composition initially comprising a polymeric material and 20 to 70% by weight of a compatible plasticizer therefor and from which composition at least a portion of said plasticizer has been removed, said separator element thereby being in a preconditioned state conducive to absorption of electrolytic solution.

16. A rechargeable battery structure according to claim 15 wherein the removed plasticizer has been replaced with a battery electrolyte solution.

18. A rechargeable battery structure according to claim 15 wherein at least one of said collector element foils comprises an open-mesh grid.

19. A rechargeable battery structure according to claim 18 wherein said at least one collector element is at least partially embedded in the electrode element interfacing therewith.

20. A rechargeable battery structure according to claim 18 wherein said structure comprises an additional bonded film of said separator composition overlaying said at least one collector element.

17. A rechargeable battery structure comprising, in sequence, a positive current collector element, a positive electrode element, a separator element, a negative electrode element, and a negative current collector element characterized in that

a) each of said collector elements comprises a flexible electrically-conductive foil,

b) each of the others of said elements comprises a flexible, self-supporting, polymeric matrix film composition;

c) each said element is bonded to contiguous elements at its respective interfaces to form a unitary flexible laminate structure; and

d) said separator element composition comprises a copolymer of vinylidene fluoride with 8 to 25% by weight hexafluoropropylene and has homogeneously distributed therein 20 to 70% by weight of a compatible organic plasticizer for said copolymer.

21. A rechargeable battery structure according to claim 17 wherein said positive electrode element composition comprises a lithium intercalation compound homogeneously distributed in a matrix of said separator element composition.

22. A rechargeable battery structure according to claim 21 wherein said lithium compound has a nominal formula selected from LiMn₂ O₄, LiCoO₂, and LiNiO₂.

23. A rechargeable battery structure according to claim 22 wherein said lithium compound has the formula Li_1+x Mn₂ O₄ where 0≦

x≦

1.

24. A rechargeable battery structure according to claim 21 wherein said negative electrode element composition comprises a carbon intercalation compound homogeneously distributed in a matrix of said separator element composition.

25. A rechargeable battery structure according to claim 24 wherein said carbon compound is selected from the group consisting of petroleum coke and graphite.

26. A rechargeable battery structure comprising a laminate structure according to claim 24 from which at least a portion of said plasticizer has been extracted.

27. A rechargeable battery structure comprising a laminate structure according to claim 24 in which at least a portion of said plasticizer has been replaced with a lithium battery electrolyte solution.

28. A rechargeable battery structure according to claim 26 wherein said flexible laminate structure is arranged in a manifold zig-zag fashion whereby respective portions of the separate continuous positive and negative collector elements are in electrical contact.

29. A rechargeable battery structure according to claim 26 which further comprises a moisture-proof barrier material forming a hermetically sealed enclosure about said flexible laminate structure.

30. A rechargeable battery structure according to claim 29 which further comprises means individually communicating electrically between said respective positive and negative current collector elements and the exterior of said enclosure.

31. A rechargeable battery structure according to claim 30 wherein said communicating means comprises:

a) a first electrically conductive member in electrical contact within said enclosure with one of said collector elements;

b) means associated with said first member for piercing said enclosure barrier material to thereby communicate electrically with the exterior of said enclosure;

c) a second member engaging said first member at the exterior of said enclosure; and

d) means actuated by the engagement of said first and second members for maintaining a hermetic seal about the pierced area of said enclosure barrier material.

32. A rechargeable battery structure according to claim 31 wherein said first member comprises means for preventing electrical contact with the other of said collector elements.