Separator and electrochemical device including the same

Patent metadata

Field	Value
Publication number	US-11245158-B2
Application number	US-201715774049-A
Country	US
Kind code	B2
Filing date	Jun 8, 2017
Priority date	Jun 8, 2016
Publication date	Feb 8, 2022
Grant date	Feb 8, 2022

Abstract

Disclosed are a separator and an electrochemical device including the same. The separator includes: a porous substrate having a plurality of pores; and a pair of porous coating layers formed on at least one surface of the porous substrate, and including a plurality of inorganic particles and a binder disposed partially or totally on the surface of the inorganic particles to connect and fix the inorganic particles with each other, wherein the binder is used in an amount of 5-40 wt % based on the total weight of the porous coating layer, the inorganic particles include boehmite particles, the binder includes a fluorine-based binder and a rubber-based binder, and the fluorine-based binder and the rubber-based binder are used at a weight ratio of 80:20-99.9:0.1.

First claim

What is claimed is:

1. A separator comprising:
a porous substrate having a plurality of pores; and
a pair of porous coating layers formed on at least one surface of the porous substrate, and including a plurality of inorganic particles and a binder disposed partially or totally on the surface of the inorganic particles to connect and fix the inorganic particles with each other,
wherein the binder is used in an amount of 5-40 wt % based on the total weight of the porous coating layer,
the inorganic particles include boehmite particles and non-boehmite particles other than the boehmite particles,
wherein the boehmite particles have a smaller average particle diameter compared to the average particle diameter of the non-boehmite particles, and
the binder includes a fluorine-based binder and a rubber-based binder, and the fluorine-based binder and the rubber-based binder are used at a weight ratio of 85:15 to 90:10,
wherein the boehmite particles have an average particle diameter of 0.05 μm to 0.4 μm, and the non-boehmite particles have an average particle diameter of 0.5 μm to 3 μm, wherein the weight ratio of the non-boehmite particles to the boehmite particles is 85:15 to 95:5.

2. The separator according to claim 1 , wherein the fluorine-based binder is any one selected from the group consisting of polyvinylidene fluoride, polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichloroethylene, polytetrafluoroethylene and polychlorotrifluoroethylene, or a mixture of at least two of them.

3. The separator according to claim 1 , wherein the rubber-based binder is any one selected from the group consisting of nitrile-butadiene rubber, hydrated nitrile-butadiene rubber, styrene-butadiene rubber, hydrated styrene-butadiene rubber and silicone rubber, or a mixture of at least two of them.

4. The separator according to claim 1 , wherein the non-boehmite particles comprise inorganic particles having a dielectric constant of 5 or more, inorganic particles capable of transporting lithium ions or a mixture thereof.

5. The separator according to claim 4 , wherein the inorganic particles having a dielectric constant of 5 or more comprise BaTiO 3 , Pb(Zr,Ti)O 3 (PZT), Pb_hd 1 - x La x Zr 1-y Ti y O 3 (PLZT), PB(Mg 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 or a mixture thereof.

6. The separator according to claim 4 , wherein the inorganic particles capable of transporting lithium ions comprise 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 -based 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 -based glass (Li x Si y S z , 0<x<3, 0<y<2, 0<z<4), P 2 S 5 -based glass (Li x P y S z , 0<x<3, 0<y<3, 0<z<7) or a mixture thereof.

7. The separator according to claim 1 , wherein the porous substrate is a polyolefin-based porous substrate.

8. The separator according to claim 7 , wherein the polyolefin-based porous substrate comprises any one polymer selected from the group consisting of polyethylene, polypropylene, polybutylene and polypentene, or a combination thereof.

9. The separator according to claim 1 , wherein the porous substrate has a thickness of 5-50 μm, a pore size of 0.01-50 μm and a porosity of 10-95%.

10. An electrochemical device comprising a cathode, an anode and a separator interposed between the cathode and the anode, wherein the separator is the separator as defined in claim 1 .

11. The electrochemical device according to claim 10 , which is a lithium secondary battery.

12. The separator according to claim 1 , wherein a heat shrinkage in a machine direction (MD) is from 14% to 16%, and a heat shrinkage in a transverse direction (TD) is 14%.

13. The separator according to claim 1 , wherein an air permeation time is 434 s/100 mL to 446 s/100 mL.

Assignees

• Lg Energy Solution Ltd

Inventors

• Sung Dong-Wook
• Gu Min-Ji

Classifications

• H01M50/491

  Porosity · CPC title

• H01M50/426

  Fluorocarbon polymers · CPC title

• H01M50/417

  Polyolefins · CPC title

• H01M50/457

  comprising three or more layers · CPC title

• H01M50/451 Primary

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