Separator and electrochemical device having the same

Patent metadata

Field	Value
Publication number	US-9853268-B2
Application number	US-201414191738-A
Country	US
Kind code	B2
Filing date	Feb 27, 2014
Priority date	Apr 20, 2012
Publication date	Dec 26, 2017
Grant date	Dec 26, 2017

Abstract

The present invention refers to a method of preparing a separator, a separator prepared therefrom and an electrochemical device having the separator. The method of preparing a separator according to the present invention comprises providing a planar and porous substrate having multiple pores; and coating a first slurry on at least one surface of the porous substrate through a slot section to form a porous coating layer, while continuously coating a second slurry on the porous coating layer through a slide section adjacent to the slot section to form a layer for adhesion with an electrode, the first slurry comprising inorganic particles, a first binder polymer and a first solvent, and the second slurry comprising a second binder polymer and a second solvent.

First claim

What is claimed is:

1. A method of preparing a separator, comprising:
providing a planar and porous substrate having multiple pores;
providing a slot-die comprising a slot section and a slide section; and
coating a first slurry on at least one surface of the porous substrate through the slot section to form a porous coating layer, while continuously coating a second slurry on the porous coating layer through the slide section adjacent to the slot section only by the force of gravity to form a layer for adhesion with an electrode,
wherein the first slurry for forming the porous coating layer comprises inorganic particles, a first binder polymer and a first solvent,
wherein the second slurry for forming the layer for adhesion comprises a second binder polymer and a second solvent,
wherein the first binder polymer and the second binder polymer are each independently selected from polyvinylidene fluoride-co-hexafluoro propylene, polyvinylidene fluoride-co-trichloro ethylene, polyvinylidene fluoride-co-chlorotrifluoro ethylene, polymethyl methacrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinylacetate, polyethylene-co-vinyl acetate, polyethylene oxide, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethyl pullulan, cyanoethyl polyvinylalcohol, cyanoethyl cellulose, cyanoethyl sucrose, pullulan, carboxyl methyl cellulose, acrylonitrile-styrene-butadiene copolymer, polyimide or a mixture thereof,
wherein the first slurry and the second slurry each independently have a viscosity of 10 to 20 cp,
wherein the first slurry is discharged at a rate faster than that of the second slurry,
wherein the layer for adhesion has a thickness of 0.0005 μm to 1 μm, and
wherein the slide section is inclined to form an angle (θ) of 10 to 60° with the slot section.

2. The method of claim 1 , wherein the first slurry is discharged at a rate of 500 to 2,000 ml/min, and the second slurry is discharged at a rate of 200 to 1,200 ml/min.

3. The method of claim 1 , wherein the layer for adhesion with an electrode has a thickness satisfying 1/10 or less of the thickness of the porous coating layer.

4. The method of claim 1 , wherein the porous substrate is a polyolefin-based porous membrane.

5. The method of claim 1 , wherein the slot section and the slide section are formed in an integrated slide-slot die, or independently formed in a slot die and a slide die, respectively.

6. The method of claim 1 , wherein the inorganic particles have an average diameter of 0.001 to 10 μm.

7. The method of claim 1 , wherein the inorganic particles are selected from inorganic particles having a dielectric constant of 5 or higher, inorganic particles having the ability to transport lithium ions, or a mixture thereof.

8. The method of claim 7 , wherein the inorganic particles having a dielectric constant of 5 or higher are 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 O 3 (PLZT, 0<x<1, 0<y<1), (1-x) Pb(Mg 1/3 Nb 2/3 )O 3-x PbTiO 3 (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, TiO 2 inorganic particles or a mixture thereof.

9. The method of claim 7 , wherein the inorganic particles having the ability to transport lithium ions are selected from 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, or a mixture thereof.

10. A separator prepared by the method of claim 1 .

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

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

Assignees

• Lg Chemical Ltd
• Toray Industries

Inventors

• Ryu Bo-Kyung
• Lee Joo-Sung
• Kim Jong-Hun

Classifications

• H01G11/52 Primary

  Separators · CPC title

• H01M50/451

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

• H01M50/491

  Porosity · CPC title

• H01M50/403 Primary

  Manufacturing processes of separators, membranes or diaphragms · CPC title

• H01M2/166

  Electricity · mapped topic