Electrode for secondary battery, preparation thereof, and secondary battery and cable-type secondary battery comprising the same

Patent metadata

Field	Value
Publication number	US-9293783-B2
Application number	US-201414477305-A
Country	US
Kind code	B2
Filing date	Sep 4, 2014
Priority date	May 7, 2013
Publication date	Mar 22, 2016
Grant date	Mar 22, 2016

Abstract

The present disclosure provides a sheet-form electrode for a secondary battery, comprising a current collector; an electrode active material layer formed on one surface of the current collector; a conductive layer formed on the electrode active material layer and comprising a conductive material and a binder; and a first porous supporting layer formed on the conductive layer. The sheet-form electrode for a secondary battery according to the present disclosure has supporting layers on at least one surfaces thereof to exhibit surprisingly improved flexibility and prevent the release of the electrode active material layer from a current collector even if intense external forces are applied to the electrode, thereby preventing the decrease of battery capacity and improving the cycle life characteristic of the battery.

First claim

What is claimed is:

1. A sheet-form electrode for a secondary battery, comprising:
a current collector;
an electrode active material layer formed on one surface of the current collector;
a conductive layer formed on the electrode active material layer and comprising a conductive material and a binder; and
a first porous supporting layer formed on the conductive layer,
wherein the sheet-form electrode is formed in a substantially helical shape defined by a general spring form, in which the electrode turns around a longitudinal axis while moving along the longitudinal axis.

2. The electrode for a secondary battery according to claim 1 , wherein the current collector comprises stainless steel, aluminum, nickel, titanium, sintered carbon, or copper; stainless steel treated with carbon, nickel, titanium or silver on a surface thereof; an aluminum-cadmium alloy; a non-conductive polymer treated with a conductive material on a surface thereof; a conductive polymer; a metal paste comprising metal powders of Ni, Al, Au, Ag, Pd/Ag, Cr, Ta, Cu, Ba or ITO; or a carbon paste comprising carbon powders of graphite, carbon black or carbon nanotube.

3. The electrode for a secondary battery according to claim 1 , wherein the current collector is in the form of a mesh.

4. The electrode for a secondary battery according to claim 1 , wherein the current collector further comprises a primer coating layer consisting of a conductive material and a binder.

5. The electrode for a secondary battery according to claim 4 , wherein the conductive material of the primer coating layer comprises any one selected from the group consisting of carbon black, acetylene black, ketjen black, carbon fiber, carbon nanotube, graphene and a mixture thereof.

6. The electrode for a secondary battery according to claim 4 , wherein the binder of the primer coating layer is selected from the group consisting of polyvinylidene fluoride (PVDF), polyvinylidene fluoride-co-hexafluoro propylene, polyvinylidene fluoride-co-trichloroethylene, polybutyl acrylate, polymethyl methacrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinylacetate, polyethylene-co-vinyl acetate, polyethylene oxide, polyarylate, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethylpullulan, cyanoethylpolyvinylalcohol, cyanoethylcellulose, cyanoethylsucrose, pullulan, carboxyl methyl cellulose, styrene-butadiene rubber, acrylonitrile-styrene-butadiene copolymer, polyimide and a mixture thereof.

7. The electrode for a secondary battery according to claim 1 , wherein the current collector has a plurality of recesses on at least one surface thereof.

8. The electrode for a secondary battery according to claim 7 , wherein the plurality of recesses are continuously patterned or intermittently patterned recesses.

9. The electrode for a secondary battery according to claim 8 , wherein the continuous patterned recesses are formed with spacing apart with each other in a longitudinal direction.

10. The electrode for a secondary battery according to claim 8 , wherein the intermittently patterned recesses are formed by a plurality of holes.

11. The electrode for a secondary battery according to claim 10 , wherein the plurality of holes are each of a circular or polygonal shape.

12. The electrode for a secondary battery according to claim 1 , wherein the first supporting layer is a mesh-form porous membrane or a non-woven fabric.

13. The electrode for a secondary battery according to claim 1 , wherein the first supporting layer is made of any one selected from the group consisting of high-density polyethylene, low-density polyethylene, linear low-density polyethylene, ultra-high molecular weight polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, polyester, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyethersulfone, polyphenylene oxide, polyphenylene sulfide, polyethylene naphthalate, and a mixture thereof.

14. The electrode for a secondary battery according to claim 1 , wherein the first supporting layer further comprises a conductive material-coating layer having a conductive material and a binder thereon.

15. The electrode for a secondary battery according to claim 14 , wherein the conductive material of the conductive material-coating layer and the binder of the conductive material-coating layer are present in a weight ratio of 80:20 to 99:1 in the conductive material-coating layer.

16. The electrode for a secondary battery according to claim 1 , wherein the conductive layer is formed from a mixture of the conductive material and the binder in a weight ratio of 1:10 to 8:10.

17. The electrode for a secondary battery according to claim 1 , wherein the conductive layer has a pore size of 0.01 to 5 μm and a porosity of 5 to 70%.

18. The electrode for a secondary battery according to claim 1 , wherein the first porous supporting layer further comprises a porous coating layer comprising a mixture of inorganic particles and a binder polymer thereon.

19. The electrode for a secondary battery according to claim 1 , which further comprises a second supporting layer formed on another surface of the current collector.

20. The electrode for a secondary battery according to claim 19 , wherein the second supporting layer is a polymer film made of any one selected from the group consisting of polyolefin, polyester, polyimide, polyamide and a mixture thereof.

21. The electrode for a secondary battery according to claim 1 , wherein when the electrode for a secondary battery is used as an anode, the electrode active material layer comprises an active material selected from the group consisting of natural graphite, artificial graphite, or carbonaceous material; lithium-titanium complex oxide (LTO), and metals (Me) including Si, Sn, Li, Zn, Mg, Cd, Ce, Ni and Fe; alloys of the metals; an oxide (MeOx) of the metals; a complex of the metals and carbon; and a mixture thereof, and
when the electrode for a secondary battery is used as a cathode, the electrode active material layer comprises an active material selected from the group consisting of LiCoO 2 , LiNiO 2 , LiMn 2 O 4 , LiCoPO 4 , LiFePO 4 , LiNiMnCoO 2 , LiNi 1-x-y-z Co x M1 y M2 x O 2 (wherein M1 and M2 are each independently selected from the group consisting of Al, Ni, Co, Fe, Mn, V, Cr, Ti, W, Ta, Mg and Mo, and x, y and z are each independently an atomic fraction of oxide-forming elements, in which 0≦x<0.5, 0≦y<0.5, 0≦z<0.5, and x+y+z≦1), and a mixture thereof.

22. A method of preparing a sheet-form electrode for a secondary battery, comprising:
(S1) applying a slurry containing an electrode active material on one surface of a current collector, followed by drying, to form an electrode active material layer;
(S2) applying a slurry containing a conductive material and a binder on a surface of the electrode active material layer;
(S3) forming a first porous supporting layer on the applied slurry containing the conductive material and the binder;
(S4) compressing the resultant obtained in step (S3) to form a conductive layer which is adhered between the electrode active material layer and the first porous supporting layer to be integrated with each other; and
(S5) forming the sheet-form electrode into a substantially helical shape defined by a general spring form, in which the electrode turns around a longitudinal axis while moving along the longitudinal axis.

23. The method according to claim 22 , wherein in the

Assignees

• Lg Chemical Ltd

Inventors

• Kwon Yo-Han
• Jung Hye-Ran
• Kim Eun-Kyung
• Kim Je-Young
• Kim Hyo-Mi

Classifications

• H01M10/058

  Construction or manufacture · CPC title

• H01M4/587

  for inserting or intercalating light metals · CPC title

• H01M4/581

  Chalcogenides or intercalation compounds thereof · CPC title

• H01M4/663

  containing carbon or carbonaceous materials as conductive part, e.g. graphite, carbon fibres · CPC title

• H01M4/0409

  by a doctor blade method, slip-casting or roller coating · CPC title