Method of making a laminated lithium-ion rechargeable battery cell

• US 5,470,357 A
• Filed: 04/26/1995
• Issued: 11/28/1995
• Est. Priority Date: 03/05/1993
• Status: Expired due to Term

• Current Assignee: Valence Technology Incorporated (Lithium Werks B.V.)
• Original Assignee: Bell Communications Research, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Shokoohi, Frough K., Tarascon, Jean-Marie, Warren, Paul C., Schmutz, Caroline N.
• Primary Examiner(s): Maples, John S.
• Application Number:
  US08/428,970
• Time in Patent Office: 216 Days
• Field of Search: 29/623.5, 29/623.1, 429/192
• US Class Current: 29/623.5
• 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: Y10T 29/49108 Electric battery cell making
• CPC Class Codes: Y10T 29/49115 including coating or impregnating

Abstract

Li-ion rechargeable battery cell electrode and electrolyte/separator elements formulated as layers of plasticized polymeric matrix compositions are laminated with electrically conductive collector elements to form a unitary battery cell structure. Adhesion between the electrode and collector elements is enhanced by pretreatment of the collector elements in which a 0.25% to 3.0% solution of a polymeric material compatible with said matrix polymer is applied to a collector foil or grid and dried to form a coated film, and the resulting coated collector element is heated within the range of about 250° to 450° C. for about 5 to 60 seconds.

Claims

1. A method of making a rechargeable battery structure which comprises arranging contiguously 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 electrode and separator elements comprises a flexible, polymeric matrix film composition,

b) each of said collector elements comprises a flexible electrically-conductive foil which has been surface treated with a polymeric material compatible with the matrix composition of its contiguous electrode, and

c) said method further comprises bonding each said element to contiguous elements at its respective interfaces by the application of heat and pressure to form a unitary flexible laminate structure.

2. A method according to claim 1

characterized in that the surface treatment of a collector element comprises:

a) coating the surface of said collector element with a solution comprising about 0.25% to 3.0% of said polymeric material, and

b) drying to remove the solvent.

3. A method according to claim 1 wherein the surface treatment further comprises heating the coated collector element within the range of about 250°

to 450°

C. for about 5 to 60 seconds.

4. A method according to claim 3 wherein at least one of said collector element foils comprises an open-mesh grid and said method further comprises respectively bonding at least one of said positive and negative collector elements to said positive and negative electrode elements prior to bonding said electrode elements to said separator element.

5. A method according to claim 3 wherein said collector element surface is coated from a solution comprising about 0.5% to 1.5% of said polymeric material and said coated collector element is heated within the range of about 300°

to 350°

C. for about 5 to 30 seconds.

6. A method according to claim 5 wherein said collector element surface is coated from a solution comprising about 0.5% of said polymeric material and said coated collector element is heated at about 340°

C. for about 5 to 20 seconds.

7. A method according to claim 2 wherein:

a) at least one of said collector element foils comprises an open-mesh grid;

b) said polymeric matrix 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 an organic plasticizer compatible with said copolymer; and

c) said polymeric treatment material comprises a copolymer of vinylidene fluoride with 6% to 25% by weight hexafluoropropylene.

8. A method according to claim 7

characterized in that the surface treatment of a collector element comprises:

a) coating the surface of said collector element by applying thereto a solution comprising about 3.0% each of said treatment copolymer and said matrix plasticizer, and

b) drying said coated collector element to remove the solvent.