Secondary battery with improved life characteristics

Patent metadata

Field	Value
Publication number	US-2018123107-A1
Application number	US-201715851068-A
Country	US
Kind code	A1
Filing date	Dec 21, 2017
Priority date	Apr 4, 2014
Publication date	May 3, 2018
Grant date	—

Abstract

The present disclosure refers to a secondary battery which comprises a high-voltage cathode active material and a separator whose pores are not obstructed even though being used together with the high-voltage cathode active material, thereby preventing the obstruction of pores in the separator and the formation of a dendrite in the anode and eventually providing good battery life performance.

First claim

What is claimed is:

1 . An electrode assembly comprising a cathode, an anode, and a separator interposed between the cathode and the anode,
wherein the cathode comprises a cathode active material capable of being applied at a high voltage, and the separator comprises a porous substrate and a porous coating layer formed on only one surface of the porous substrate and comprising inorganic particles and an organic binder polymer, and has pores whose longest diameter ranges from 50 nm to 1 μm, wherein the porous coating layer is formed in a thickness of 0.5 to 20 μm, and wherein the porous coating layer is disposed to be faced with the anode.

2 . An electrode assembly comprising a cathode, an anode, and a separator interposed between the cathode and the anode,
wherein the cathode comprises a cathode active material capable of being applied at a high voltage, and the separator comprises a porous substrate and a porous coating layer formed on only one surface of the porous substrate and comprising inorganic particles and an organic binder polymer, and has pores whose longest diameter ranges from 10 nm to 5 μm, wherein the porous coating layer is formed in a thickness of 0.5 to 20 μm, and wherein the porous coating layer is disposed to be faced with the anode, wherein the inorganic particles have a size of 0.01 to 10 μm.

3 . An electrode assembly comprising a cathode, an anode, and a separator interposed between the cathode and the anode,
wherein the cathode comprises a cathode active material capable of being applied at a high voltage, and the separator comprises a porous substrate and a porous coating layer formed on only one surface of the porous substrate and comprising inorganic particles and an organic binder polymer, and has pores whose longest diameter ranges from 10 nm to 5 μm, wherein the porous coating layer is formed in a thickness of 0.5 to 20 μm, and wherein the porous coating layer is disposed to be faced with the anode, wherein the porous substrate is a porous membrane obtained from a polyethylene resin, a polypropylene/polyethylene/polypropylene resin, or a polypropylene resin.

4 . The electrode assembly of claim 1 , wherein the cathode active material is any one selected from lithium oxides of formula (I) to (IV) and a mixture thereof:
Li x [Ni a Co b Mn c ]O 2   (I)
(0.95≤x≤1.05, 0≤a, b, c≤1, a+b+c=1, and a and c are not simultaneously 0),
Li[Li x Ni a Co b Mn c ]O 2   (II)

(0.05≤x≤0.6, and x+a+b+c=1),
Li x [Ni a Co b Mn c ]O 2   (III)

(0.95≤x≤1.05, 0<a, b, c≤1, a+b+c=1, and 0.4<c<1),
LiMn 2-x M x O 4   (IV)

(M is at least one element selected from the group consisting of Ni, Co, Fe and Al, and 0≤x≤2).

5 . The electrode assembly of claim 1 , wherein the cathode active material has an average diameter of 5 to 15 μm.

6 . The electrode assembly of claim 1 , wherein the longest diameter of pores ranges from 50 to 500 nm.

7 . The electrode assembly of claim 1 , wherein the porous coating layer is formed in a thickness of 3 to 6 μm.

8 . The electrode assembly of claim 1 , wherein the inorganic particles have a dielectric constant of 5 or higher.

9 . The electrode assembly of claim 1 , wherein the inorganic particles are selected from the group consisting of BaTiO 3 , Pb(Zr,Ti)O 3 (PZT), Pb 1-x La x Zr 1-y Ti y O 3 (PLZT), Pb(Mg 1/3 Nb 2/3 )O 3 —PbTiO 3 (PMN-PT), hafnia (HfO 2 ), SrTiO 3 , SnO 2 , CeO 2 , MgO, NiO, CaO, ZnO, ZrO 2 , Y 2 O 3 , Al 2 O 3 , TiO 2 , SiC inorganic particles and a mixture thereof.

10 . The electrode assembly of claim 1 , wherein the inorganic particles have a size of 0.01 to 10 μm.

11 . The electrode assembly of claim 1 , wherein the inorganic particles are present in an amount of 50 to 99 wt % based on 100 wt % of the total amount of the inorganic particles and the organic binder polymer.

12 . The electrode assembly of claim 1 , wherein the organic binder polymer is selected from the group consisting of polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichloroethylene, polymethyl methacrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinyl acetate, polyethylene-co-vinyl acetate, polyethylene oxide, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, cyanoethyl cellulose, cyanoethyl sucrose, pullulan, carboxyl methyl cellulose, acrylonitrile-styrene-butadiene copolymer, polyimide, and a mixture thereof.

13 . The electrode assembly of claim 1 , wherein the porous substrate is a porous membrane obtained from a polyethylene resin, a polypropylene/polyethylene/polypropylene resin, or a polypropylene resin.

14 . The electrode assembly of claim 1 , wherein the porous substrate is a non-woven fabric.

15 . The electrode assembly of claim 2 , wherein the cathode active material is any one selected from lithium oxides of formula (I) to (IV) and a mixture thereof:
Li x [Ni a Co b Mn c ]O 2   (I)
(0.95≤x≤1.05, 0≤a, b, c≤1, a+b+c=1, and a and c are not simultaneously 0),
Li[Li x Ni a Co b Mn c ]O 2   (II)

(0.05≤x≤0.6, and x+a+b+c=1),
Li x [Ni a Co b Mn c ]O 2   (III)

(0.95≤x≤1.05, 0<a, b, c≤1, a+b+c=1, and 0.4<c<1),
LiMn 2-x M x O 4   (IV)

(M is at least one element selected from the group consisting of Ni, Co, Fe and Al, and 0≤x≤2).

16 . The electrode assembly of claim 2 , wherein the inorganic particles have a dielectric constant of 5 or higher.

17 . The electrode assembly of claim 2 , wherein the porous coating layer is formed in a thickness of 3 to 6 μm.

18 . The electrode assembly of claim 3 , wherein the cathode active material is any one selected from lithium oxides of formula (I) to (IV) and a mixture thereof:
Li x [Ni a Co b Mn c ]O 2   (I)
(0.95≤x≤1.05, 0≤a, b, c≤1, a+b+c=1, and a and c are not simultaneously 0),
Li[Li x Ni a Co b Mn c ]O 2   (II)

(0.05≤x≤0.6, and x+a+b+c=1),
Li x [Ni a Co b Mn c ]O 2   (III)

(0.95≤x≤1.05, 0<a, b, c≤1, a+b+c=1, and 0.4<c<1),
LiMn 2-x M x O 4   (IV)

(M is at least one element selected from the group consisting of Ni, Co, Fe and Al, and 0≤x≤2).

19 . The electrode assembly of claim 3 , wherein the inorganic particles have a dielectric constant of 5 or higher.

20 . The electrode assembly of claim 3 , wherein the porous coating layer is formed in a thickness of 3 to 6 μm.

Assignees

• Lg Chemical Ltd
• Toray Industries

Inventors

• Yu Sung-Hoon
• Suk Jung-Don
• Kim Seok-Koo
• Yang Doo-Kyung
• Kang Yoo-Sun
• Lee Kyung-Mi
• Park Jin-Hyun

Classifications

• H01M4/525

  of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M4/131

  Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title

• H01M4/505 Primary

  of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy · CPC title

• H01M50/451

  comprising layers of only organic material and layers containing inorganic material · CPC title