Secondary energy storage device and electrode employing a multiplicity of flexible biregional fibers

• US 5,821,012 A
• Filed: 07/01/1996
• Issued: 10/13/1998
• Est. Priority Date: 04/25/1995
• Status: Expired due to Fees

• Current Assignee: AHC Patent Co.
• Original Assignee: Francis Patrick Mccullough
• Inventors: McCullough, Francis Patrick
• Primary Examiner(s): Skapars, Anthony
• Application Number:
  US08/674,124
• Time in Patent Office: 834 Days
• Field of Search: 429/209, 429/218, 429/223, 429/224, 429/249, 429/251, 429/212, 423/447.2, 423/447.1, 428/113, 428/224, 428/253, 428/288, 428/364, 428/367
• US Class Current: 429/209
• CPC Class Codes: D01F 11/14 with organic compounds, e.g. macromolecular compounds
• CPC Class Codes: D01F 8/08 with at least one polyacrylonitrile as constituent
• CPC Class Codes: D01F 9/12 Carbon filaments; Apparatus specially adapted for the manufacture thereof
• 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 2004/029 Bipolar electrodes
• CPC Class Codes: H01M 2300/0025 Organic electrolyte
• 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 4/38 of elements or alloys
• CPC Class Codes: H01M 4/485 of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy H01M4/505, H01M4/525 take precedence
• CPC Class Codes: H01M 4/587 for inserting or intercalating light metals
• CPC Class Codes: H01M 4/625 Carbon or graphite
• CPC Class Codes: H01M 4/663 containing carbon or carbonaceous materials as conductive part, e.g. graphite, carbon fibres
• 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 4/70 characterised by shape or form
• CPC Class Codes: H01M 4/806 Nonwoven fibrous fabric containing only fibres
• CPC Class Codes: H01M 6/48 with bipolar electrodes
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y10T 428/29 Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
• CPC Class Codes: Y10T 428/2913 Rod, strand, filament or fiber
• CPC Class Codes: Y10T 428/2918 : including free carbon or carbide or therewith [not as steel]
• CPC Class Codes: Y10T 428/2924 : Composite
• CPC Class Codes: Y10T 428/2933 : Coated or with bond, impregnation or core
• CPC Class Codes: Y10T 428/2967 : Synthetic resin or polymer
• CPC Class Codes: Y10T 428/2973 : Particular cross section
• CPC Class Codes: Y10T 428/30 : Self-sustaining carbon mass or layer with impregnant or other layer
• CPC Class Codes: Y10T 442/2803 : Polymeric coating or impregnation from a silane or siloxane not specified as lubricant or water repellent
• CPC Class Codes: Y10T 442/3683 : Fabric layer contains carbon or carbonaceous strand material
• CPC Class Codes: Y10T 442/629 : Composite strand or fiber material
• CPC Class Codes: Y10T 442/637 : Including strand or fiber material which is a monofilament composed of two or more polymeric materials in physically distinct relationship [e.g., sheath-core, side-by-side, islands-in-sea, fibrils-in-matrix, etc.] or composed of physical blend of chemically different polymeric materials or a physical blend of a polymeric material and a filler material

Abstract

An electrode is disclosed comprising a multiplicity of flexible biregional fibers, each fiber having an inner core region of a thermoplastic polymeric composition and a surrounding outer region of an electrically conductive carbonaceous sheath. The biregional fiber is derived from a biregional precursor fiber having an inner core region of a thermoplastic polymeric composition and a surrounding outer region of an oxidation stabilized sheath, and wherein the biregional precursor fiber is derived from a polymeric fiber comprising a single homogeneous polymeric composition, the flexible biregional fiber is particularly characterized by having a ratio of the radius of the core region with respect to the total radius of the fiber (r:R) of from about 1:4 to about 1:1.05 and a breaking twist angle of from about 4 to about 13 degrees. Also disclosed are secondary electrical storage devices employing electrodes of the invention.

Claims

1. An electrode for a secondary energy storage device, comprising a multiplicity of electrically conductive biregional fibers, each said biregional fiber having an inner region of a thermoplastic polymeric core and an outer region of a carbonaceous sheath.

2. The electrode of claim 1, wherein said biregional fiber has a breaking twist angle of from about 4 to about 13 degrees.

3. The electrode of claim 1, wherein the ratio (r:

R) of the radius of the inner core region (r) of the biregional fiber with respect to the total radius of the fiber (R) is from about 1;

4 to about 1;

1.105.

4. The electrode of claim 1, wherein the ratio (r:

R) of the radius of the inner core region (r) of the biregional fiber with respect to the total radius of the fiber (R) is from about 1;

3 to about 1;

1.125.

5. The electrode of claim 1, wherein said biregional fiber has a Young'"'"'s Modulus of from less than 1 MM to about 30 MM psi and a bending strain value of greater than 0.01% but less than 50%.

6. The electrode of claim 1, wherein said biregional fiber has a density of from about 1.65 to about 1.87 g/cm³, a Young'"'"'s Modulus of from about less than 1 MM psi to about 30 MM psi, and a bending strain value of greater than 0.1% but less than 30%.

7. The electrode of claim 1, wherein said carbonized outer sheath region of the fiber is electrically conductive, and wherein said fiber has a total carbon content of less than 85% by weight, and a bulk resistivity of less than about 10¹ ohm-cm.

8. The electrode of claim 1, wherein said carbonized outer sheath region is electrically conductive, has a total carbon content of from 68% to 96% by weight, a bulk resistivity of less than about 10¹ ohm-cm.

9. The electrode of claim 1, wherein said biregional fiber has a generally circular, non-circular, or tubular cross-sectional shape and a diameter of from about 1 to about 30 micrometers.

10. The electrode of claim 1, wherein said biregional fiber is ignition resistant and has an LOI of greater than 40.

11. The electrode of claim 1, wherein said inner thermoplastic core region and said surrounding outer carbonaceous sheath region are continuous and do not present an intermediate boundary or discontinuity between the regions.

12. The electrode of claim 1, wherein said biregional fiber is derived from a biregional precursor fiber, said precursor fiber having an inner region of a thermoplastic polymeric core and a surrounding outer region of a stabilized sheath, and wherein said inner thermoplastic core region and said outer stabilized sheath region are continuous and do not present an intermediate boundary or discontinuity between the regions.

13. The electrode of claim 11, wherein said biregional precursor fiber is derived from a single homogeneous thermoplastic polymeric composition.

14. The electrode of claim 13, wherein said polymeric composition comprises an acrylic polymer selected from the group consisting of copolymers and terpolymers of acrylonitrile, wherein said copolymers and terpolymers contain at least 85 mole percent acrylic units and up to 15 mole percent of one or more vinyl monomers copolymerized therewith.

15. The electrode of claim 14, wherein said vinyl monomers copolymerizable with acrylonitrile include methacrylic acid esters and acrylic acid esters such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, methyl acrylate and ethyl acrylate;

vinyl esters such as vinyl acetate and vinyl propionate;

acrylic acid, methacrylic acid, maleic acid, itaconic acid and the salts thereof;

vinylsulfonic acid and the salts thereof.

16. The electrode of claim 11, wherein said polymeric composition is an acrylic resin selected from the group consisting of copolymers and terpolymers of acrylonitrile, wherein said copolymers and terpolymers contain less than 85 mole percent acrylic units and more than 15 mole percent of one or more plasticizer polymers copolymerized therewith.

17. The electrode of claim 16, wherein said copolymers and terpolymers contain up to 35 mole percent of one or more plasticizer polymers.

18. The electrode of claim 17, wherein said plasticizer polymer is selected from the group consisting of vinyl chloride, methyl acrylate, methyl methacrylate, polyvinyl chloride, cellulose esters, phthalates, adipates, and sebacate esters, polyols such as ethylene glycol and its derivatives, tricresyl phosphate, caster oil, and mixtures thereof.

19. The electrode of claim 11, wherein said polymeric composition comprises an unfiltered acrylic polymer containing from about 0.0001 to about 5% by weight particulate matter having a diameter of less than about 0.1 microns.