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

Patent metadata

Field	Value
Publication number	US-10050311-B2
Application number	US-201715410110-A
Country	US
Kind code	B2
Filing date	Jan 19, 2017
Priority date	Dec 12, 2012
Publication date	Aug 14, 2018
Grant date	Aug 14, 2018

Abstract

The present invention provides an electrode for a secondary battery, more specifically an electrode for a secondary battery, comprising a current collector; an electrode active material layer formed on at least one surface or the whole outer surface of the current collector; a conductive material-coating layer formed on the top surface of the electrode active material layer and comprising a conductive material and a first polymer binder; and a porous coating layer formed on the top surface of the conductive material-coating layer and comprising a second polymer binder. Also, the present invention provides a secondary battery and a cable-type secondary battery comprising the electrode.

First claim

What is claimed is:

1. A cable-type secondary battery having a horizontal cross section and extending longitudinally, comprising
a core for supplying lithium ions, the core including an electrolyte;
an inner electrode comprising an open-structured inner current collector surrounding an outer surface of the core and an inner electrode active material layer surrounding an outer surface of the inner current collector;
a separation layer surrounding an outer surface of the inner electrode to prevent a short circuit between electrodes; and
an outer electrode surrounding an outer surface of the separation layer, comprising an outer current collector, an outer electrode active material layer, a conductive material-coating layer comprising a conductive material and a first polymer binder, and a porous coating layer comprising a second polymer binder and inorganic particles, wherein the conductive material-coating layer does not include an active material,
wherein in the porous coating layer, the inorganic particles are bound to each other by the second polymer binder such that the inorganic particles are in contact with each other and interstitial volumes are formed between the inorganic particles, the interstitial volumes forming pores of the porous coating layer, and
wherein the inorganic particles are:
inorganic particles having a dielectric constant of 5 or higher selected from the group consisting of BaTiO 3 , Pb(Zr x , Ti 1-x )O 3 (PZT, 0<x<1), Pb 1-x La x Zr 1-y Ti y O 3 (PLZT, 0<x<1, 0<y<1), (1−x)Pb(Mg 1/3 Nb 2/3 )O 3-x PbTi O3 (PMN-PT, 0<x<1), hafnia (HfO 2 ), SrTiO 3 , SnO 2 , CeO 2 , MgO, NiO, CaO, ZnO, ZrO 2 , Y 2 O 3 , Al 2 O 3 , SiC, SiO 2 , AlOOH, Al(OH) 3 , TiO 2 and a mixture thereof,

inorganic particles having the ability to transport lithium ions selected from the group consisting of lithium phosphate (Li 3 PO 4 ), lithium titanium phosphate (Li x Ti y (PO 4 ) 3 , 0<x<2, 0<y<3), lithium aluminum titanium phosphate (Li x Al y Ti z (PO 4 ) 3 , 0<x<2, 0<y<1, 0<z<3), (LiAlTiP) x O y type glass (0<x<4, 0<y<13), lithium lanthanum titanate (Li x La y TiO 3 , 0<x<2, 0<y<3), lithium germanium thiophosphate (Li x Ge y P z S w , 0<x<4, 0<y<1, 0<z<1, 0<w<5), lithium nitride (Li x N y , 0<x<4, 0<y<2), SiS 2 type glass (Li x Si y S z , 0<x<3, 0<y<2, 0<z<4), P 2 S 5 type glass (Li x P y S z , 0<x<3, 0<y<3, 0<z<7) inorganic particles, and a mixture thereof, or
a mixture thereof.

2. The cable-type secondary battery according to claim 1 , wherein the conductive material and the first polymer binder in the conductive material-coating layer are present in a weight ratio of 1:10 to 8:10.

3. The cable-type secondary battery according to claim 1 , wherein the conductive material-coating layer has pores having a size of 0.01 μm to 5 μm, and a porosity of 5% to 70%.

4. The cable-type secondary battery according to claim 1 , wherein the conductive material comprises any one selected from the group consisting of carbon black, acetylene black, ketjen black, carbon fiber, carbon nanotube, graphene and a mixture thereof.

5. The cable-type secondary battery according to claim 1 , wherein the first polymer binder is selected from the group consisting of polyvinylidene fluoride (PVDF), hexafluoro propylene (HFP), 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.

6. The cable-type secondary battery according to claim 1 , wherein the porous coating layer has pores having a size of 0.01 μm to 10 μm, and a porosity of 5% to 95%.

7. The cable-type secondary battery according to claim 1 , wherein the inorganic particles and the second polymer binder in the porous coating layer are present in a weight ratio of 10:90 to 95:5.

8. The cable-type secondary battery according to claim 1 , wherein the inorganic particles have an average diameter of 10 nm to 5 μm.

9. The cable-type secondary battery according to claim 1 , wherein the second polymer binder is selected from the group consisting of polyvinylidene fluoride (PVDF), hexafluoro propylene (HFP), 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.

10. The cable-type secondary battery according to claim 1 , wherein the open-structured inner current collector is a wound wire form, a wound sheet form or a mesh form.

11. The cable-type secondary battery according to claim 1 , wherein the outer electrode is an anode, and the outer electrode active material layer comprises an active material selected from the group consisting of metals (Me) including Si, Sn, Li, Al, Ag, Bi, In, Ge, Pb, Pt, Ti, Zn, Mg, Cd, Ce, Cu, Co, Ni and Fe; alloys of the metals; oxides (MeO x ) of the metals; and a mixture thereof.

12. The cable-type secondary battery according to claim 1 , wherein in the outer electrode,
the porous coating layer is formed to surround the outer surface of the separation layer, the conductive material-coating layer is formed to surround the porous coating layer, the outer electrode active material layer is formed to surround the conductive material-coating layer, and the outer current collector is formed to surround an outer surface of the outer electrode active material layer.

13. The cable-type secondary battery according to claim 1 , wherein the separation layer is an electrolyte layer or a separator.

14. The cable-type secondary battery according to claim 13 , wherein the electrolyte layer comprises an electrolyte selected from a gel polymer electrolyte using PEO, PVdF, PVdF-HFP, PMMA, PAN, or PVAc; and a solid electrolyte using PEO, polypropylene oxide (PPO), polyether imine (PEI), polyethylene sulphide (PES), or polyvinyl acetate (PVAc).

15. The cable-type secondary battery according to claim 14 , wherein the electrolyte layer further comprises a lithium salt.

16. The cable-type secondary battery according to claim 15 , wherein the lithium salt is selected from LiCl, LiBr, LiI, LiClO 4 , LiBF 4 , LiB 10 Cl 10 , LiPF 6 , LiCF 3 SO 3 , LiCF 3 CO 2 , LiAsF 6 , LiSbF 6 , LiAlCl 4 , CH 3 SO 3 Li, CF 3 SO 3 Li, (CF 3 SO 2 ) 2 NLi, lithium chloroborate, lower aliphatic lithium carbonate, lithium tetraphenylborate, and a mixture thereof.

17. The cable-type secondary battery according to claim 13 , wherein the separator is a porous substrate made of a polyolefin-based polymer selected from the group consisting of ethylene homopolymers, propylene homopolymers, ethylene-butene copolymers, ethylene-hexene copolymers, and ethylene-methacrylate copolymers; a porous substrate made of a polymer selected from the group consisting of polyesters, polyacetals, polyamides, polycarbonates, polyimides, polyether ether ketones, polyether sulfones, polyphenylene ox

Assignees

• Lg Chemical Ltd

Inventors

• Kwon Yo-Han
• Hong Jang-Hyuk
• Jung Hye-Ran
• Kim Je-Young
• Kim Jong-Hun

Classifications

• H01M4/62

  Selection of inactive substances as ingredients for active masses, e.g. binders, fillers · CPC title

• H01M4/75

  Wires, rods or strips · CPC title

• H01M4/366

  as layered products · CPC title

• H01M4/13 Primary

  Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof · CPC title

• H01M4/0404

  by coating on electrode collectors · CPC title