Electrically conductive, freestanding microporous polymer sheet

• US 6,524,742 B1
• Filed: 02/18/2000
• Issued: 02/25/2003
• Est. Priority Date: 02/19/1999
• Status: Expired due to Term

• Current Assignee: Amtek Research International LLC
• Original Assignee: Amtek Research International LLC
• Inventors: Young, James, Pekala, Richard W., Emanuel, James
• Primary Examiner(s): Ryan; Patrick
• Assistant Examiner(s): WILLS, MONIQUE M
• Application Number:
  US09/507,174
• Time in Patent Office: 1,103 Days
• Field of Search: 429/129,132,137,237,247
• US Class Current: 429/129
• CPC Class Codes: H01G 11/38 Carbon pastes or blends; Binders or additives therein
• CPC Class Codes: H01G 11/52 Separators
• CPC Class Codes: H01G 11/86 specially adapted for electrodes carbonisation or activation of carbon for the manufacture of electrodes H01G11/34
• CPC Class Codes: H01G 9/042 characterised by the material H01G11/22 takes precedence
• CPC Class Codes: H01M 10/0436 Small-sized flat cells or batteries for portable equipment
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 10/06 Lead-acid accumulators semi-lead accumulators H01M10/20
• CPC Class Codes: H01M 10/24 Alkaline accumulators
• CPC Class Codes: H01M 10/345 Gastight metal hydride accumulators
• CPC Class Codes: H01M 2300/0082 Organic polymers
• CPC Class Codes: H01M 2300/0085 Immobilising or gelification of electrolyte
• CPC Class Codes: H01M 4/00 Electrodes
• CPC Class Codes: H01M 4/02 Electrodes composed of, or comprising, active material
• CPC Class Codes: H01M 4/04 Processes of manufacture in general
• CPC Class Codes: H01M 4/13 Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
• CPC Class Codes: H01M 4/134 Electrodes based on metals, Si or alloys
• CPC Class Codes: H01M 4/139 Processes of manufacture
• CPC Class Codes: H01M 4/50 of manganese
• CPC Class Codes: H01M 4/505 of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
• CPC Class Codes: H01M 4/52 of nickel, cobalt or iron
• CPC Class Codes: H01M 4/56 : of lead
• CPC Class Codes: H01M 4/587 : for inserting or intercalating light metals
• CPC Class Codes: H01M 4/622 : being polymers
• CPC Class Codes: H01M 4/623 : fluorinated polymers
• CPC Class Codes: H01M 4/661 : Metal or alloys, e.g. alloy coatings H01M4/669 take precedence
• CPC Class Codes: H01M 4/8647 : consisting of more than one material, e.g. consisting of composites
• CPC Class Codes: H01M 4/96 : Carbon-based electrodes
• CPC Class Codes: H01M 50/417 : Polyolefins
• CPC Class Codes: H01M 50/46 : Separators, membranes or diaphragms characterised by their combination with electrodes
• CPC Class Codes: H01M 50/491 : Porosity
• CPC Class Codes: H01M 50/494 : Tensile strength
• CPC Class Codes: H01M 6/10 : with wound or folded electrodes
• CPC Class Codes: H01M 6/188 : Processes of manufacture
• CPC Class Codes: H01M 6/40 : Printed batteries , e.g. thin film batteries
• CPC Class Codes: Y02E 60/13 : Energy storage using capacitors
• CPC Class Codes: Y02E 60/50 : Fuel cells
• CPC Class Codes: Y10T 29/49112 : including laminating of indefinite length material
• CPC Class Codes: Y10T 29/49114 : including adhesively bonding

Abstract

A freestanding, microporous polymer sheet (52, 56) is composed of a polymer matrix binding and electrically conductive matrix. The polymer matrix preferably includes UHMWPE, and the electrically conductive matrix preferably is in powder form. The UHMWPE is of a molecular weight that provides sufficient molecular chain entanglement to form a sheet, with freestanding characteristics. Multiple microporous sheets (30) can be wound or stacked in a package filled with an electrolyte to function as electrodes in an energy storage device (86), such as a battery. Metallic layers (81, 83) can be applied to the microporous sheets to function as current collectors in such devices.

Claims

1. A freestanding, electrically conductive polymer web, comprising:

an extruded polymer matrix binding a material composition having electrical conductivity properties, the polymer matrix including an ultrahigh molecular weight polyolefin of a molecular weight that provides sufficient molecular chain entanglement to form a microporous web having freestanding characteristics and having pores encompassing a volume fraction of between about 0.20 and about 0.8.

2. The polymer web of claim 1, further comprising a metallic layer that is applied to the polymer web to form a metallized electric current collector.

3. The polymer web of claim 1, in which the material composition having electrical conductivity properties comprises an electrochemically active powder.

4. The polymer web of claim 1, in which the material composition having electrical conductivity properties comprises an electrochemically active powder in combination with an electrically conductive agent.

5. The polymer web of claim 1, in which the ultrahigh molecular weight polyolefin is ultrahigh molecular weight polyethylene.

6. The polymer web of claim 1, in which the ultrahigh molecular weight polyolefin is combined with one or more of polyvinylidene fluoride, polyvinylidene fluoride copolymer, polyethylene oxide, and polyacrylonitrile in sufficient amount to form a gelled electrolyte after introduction of a liquid electrolyte.

18. The polymer web of claim 1, in which the polymer matrix of the microporous web does not exceed a volume fraction of about 0.25.

7. In an energy storage device of a type having multiple electrodes and wound or stacked in a package filled with an electrolyte, the improvement comprising:

a microporous web having freestanding characteristics and including an extruded polymer matrix binding a material composition having electrical conductivity properties, the polymer matrix including an ultrahigh molecular weight polyolefin in an amount and of a molecular weight that provide sufficient molecular chain entanglement to form an electrode.

8. The energy storage device of claim 7, in which the material composition having electrical conductivity properties comprises an electrochemically active powder.

9. The energy storage device of claim 8, in which the electrochemically active powder includes lithium intercalation compounds including lithium nickel oxide, lithium cobalt oxide, and lithium manganese oxide;

lead (II) oxide, lead (II, III) oxide, and mixtures of lead and lead oxide;

manganese dioxide;

zinc oxide;

nickel;

zinc;

lead;

silver;

iron;

iron oxides;

metal hydrides including lanthanum-nickel (LaNi₅);

cobalt oxides;

hydroxides of nickel, zinc, and cadmium, and cobalt;

crystalline or amorphous carbonaceous materials in the form of fiber, powder, or microbeads including natural or synthetic graphite, carbon black, coke, mesocarbon microbeads, or activated carbon.

10. The energy storage device of claim 7, further comprising a metallic layer that is applied to the polymer web to form a metallized electric current collector for the energy storage device.

11. The energy storage device of claim 10, in which the metallic layer includes one of a metallic-grid, perforated metal sheet, metal film, and metal foil.

12. The energy storage device of claim 10, in which the metallic layer includes one of a metal film formed by sputter deposition on, electroless deposition on, electrodeposition on, plasma spraying on, or roll coating of a metal slurry on the microporous web;

or a porous or nonporous metal foil laminated to the microporous web.

13. The energy storage device of claim 7, gain which the ultrahigh molecular weight polyolefin is ultrahigh molecular weight polyethylene.

14. An electrode assembly formed as a multi-layer web, comprising:

a microporous separator layer positioned between and coherently bonded to a microporous anode layer and a microporous cathode layer;

the microporous separator layer formed as an extruded web from an ultrahigh molecular weight polyolefin; and

each of the microporous anode layer and microporous cathode layer formed as an extruded web from a mixture of an ultrahigh molecular weight polyolefin and a material composition having electrical conductivity properties.

15. The electrode assembly of claim 14, in which the separator layer further comprises an electrically nonconductive filler.

16. The electrode assembly of claim 14, further comprising a pair of current collector layers each of which bonded to a different one of the anode and cathode layers to form an electrochemical cell.

17. The electrode assembly of claim 14, in which the coherent bond between the separator layer and each of the anode and cathode layers is accomplished by one of extrusion or lamination.