Separator for secondary cell having excellent heat resistance and shutdown properties

Patent metadata

Field	Value
Publication number	US-2017162855-A1
Application number	US-201615366649-A
Country	US
Kind code	A1
Filing date	Dec 1, 2016
Priority date	Dec 2, 2015
Publication date	Jun 8, 2017
Grant date	—

Abstract

A separator for a secondary cell includes a porous polymer substrate having a first surface, a second surface opposing the first surface, and a plurality of pores connecting the first surface to the second surface; and heat-resistant coating layers formed on at least one of the first surface and the second surface of the porous polymer substrate and on internal surfaces of the pores using an atomic layer deposition process (ALD). Pores having a non-coated region are present in the internal surfaces of the pores.

First claim

What is claimed is:

1 . A separator for a secondary cell comprising:
a porous polymer substrate having a first surface, a second surface opposing the first surface, and a plurality of pores connecting the first surface to the second surface; and heat-resistant coating layers formed on at least one of the first surface and the second surface of the porous polymer substrate and on internal surfaces of the pores using an atomic layer deposition (ALD) process, wherein pores having a non-coated region are present in the internal surfaces of the pores.

2 . The separator of claim 1 , wherein a weight percentage of the heat-resistant coating layers is within a range from 10% to 50% based on a total weight percentage of heat-resistant coating layers coated on the first surface and the second surface of the porous polymer substrate and onto the internal surfaces of the pores at the same thickness as an average thickness (d) of the heat-resistant coating layers formed on the first surface and the second surface of the porous polymer substrate.

3 . A separator for a secondary cell comprising:
a porous polymer substrate having a first surface, a second surface opposing the first surface, and a plurality of pores connecting the first surface to the second surface; and heat-resistant coating layers formed on at least one of the first surface and the second surface of the porous polymer substrate and on internal surfaces of the pores using an atomic layer deposition process, wherein, with respect to a Gurley value of the separator, an increase in a Gurley value of a separator after the separator remains at 150° C. for one hour is 200% or greater.

4 . The separator of claim 3 , wherein the separator has a shrinkage of 5% or lower before and after remaining at 150° C. for one hour.

5 . The separator of claim 3 , wherein the separator has a melt fracture temperature of 160° C. or higher, measured by thermo-mechanical analysis (TMA).

6 . The separator of claim 3 , wherein the separator comprises pores, including a region having the heat-resistant coating layers formed thereon and a region having non-heat-resistant coating layers formed thereon in the internal surfaces of the pores.

7 . The separator of claim 1 , wherein the heat-resistant coating layers formed on the internal surfaces of the pores have a thickness of 70% or lower based on a thickness of the heat-resistant coating layers formed on the first surface and the second surface of the porous polymer substrate.

8 . The separator of claim 1 , wherein the porous polymer substrate is formed of a polyolefin-based resin.

9 . The separator of claim 1 , wherein the heat-resistant inorganic layers comprise a molecule including an atom of at least one of aluminum, calcium, magnesium, silicon, titanium, and zirconium, and an atom of at least one of carbon, nitrogen, sulfur, and oxygen.

10 . The separator of claim 1 , wherein the heat-resistant coating layers are formed of at least one of aluminum oxide, silicon oxide, titanium oxide, and zinc oxide.

11 . Amethod of manufacturing a separator for a secondary cell, the method comprising:
forming heat-resistant coating layers by repeating cycles of an atomic layer deposition process for a porous polymer substrate having a first surface, a second surface opposing the first surface, and a plurality of pores connecting the first surface to the second surface, each of the cycles of the atomic layer deposition process comprising: forming a metal compound layer containing a metal by allowing metal compound vapor including at least one of aluminum, calcium, magnesium, silicon, titanium, and zirconium to react with the first surface and the second surface of the porous polymer substrate; forming a solid ceramic layer containing a nonmetal and a metal by allowing nonmetal compound vapor including at least one of carbon, nitrogen, sulfur, and oxygen to react with a metal compound contained in the formed metal compound layer; and forming a layer containing a metal on a portion of internal surfaces of the pores by controlling an amount of the metal compound vapor supplied to an entirety of a reaction area of the porous polymer substrate, during the forming the metal compound layer and the forming the solid ceramic layer, in each of the cycles of the atomic layer deposition process.

12 . The method of claim 11 , wherein the layer containing the metal is formed on the portion of the internal surfaces of the pores by additionally controlling the number of repetitions of the cycles of the atomic layer deposition process and a reaction time required for the forming the metal compound layer.

13 . The method of claim 11 , wherein a weight percentage of the heat-resistant coating layers is within a range from 10% to 50%, based on a theoretical weight percentage thereof, and the theoretical weight percentage is defined as a total weight percentage of heat-resistant coating layers coated on the first surface and the second surface of the porous polymer substrate and onto the internal surfaces of the pores at the same thickness as an average thickness of the heat-resistant coating layers formed on the first surface and the second surface of the porous polymer substrate.

14 . The method of claim 11 , wherein the metal compound vapor is formed of at least one of AlCl 3 , tri-methyl-aluminum, Al(CH 3 ) 2 Cl, Al(C 2 H 5 ) 3 , Al(OC 2 H 5 ) 3 , Al(N(C 2 H 5 ) 2 ) 3 , Al(N(CH 3 ) 2 ) 3 , SiCl 4 , SiCl 2 H 2 , Si 2 Cl 6 , Si(C 2 H 5 )H 2 , Si 2 H 6 , TiF 4 , TiCl 4 , TiI 4 , Ti(OCH 3 ) 4 , Ti(OC 2 H 5 ) 4 , Ti(N(CH 3 ) 2 ) 4 , Ti(N(C 2 H 5 ) 2 ) 4 , Ti(N(CH 3 )(C 2 H 5 )) 4 , VOCl 3 , Zn, ZnCl 2 , Zn(CH 3 ) 2 , Zn(C 2 H 5 ) 2 , ZnI 2 , ZrCl 4 , ZrI 4 , Zr(N(CH 3 ) 2 ) 4 , Zr(N(C 2 H 5 ) 2 ) 4 , Zr(N(CH 3 )(C 2 H 5 )) 4 , HfCl 4 , HfI 4 , Hf(NO 3 ) 4 , Hf(N(CH 3 )(C 2 H 5 )) 4 , Hf(N(CH 3 ) 2 ) 4 , Hf(N(C 2 H 5 ) 2 ) 4 , TaCl 5 , TaF 5 , TaI 5 , Ta(O(C 2 H 5 )) 5 , Ta(N(CH 3 ) 2 ) 5 , Ta(N(C 2 H 5 ) 2 ) 5 , or TaBr 5 .

15 . The method of claim 11 , wherein after a preprocessing process of applying a functional group to the porous polymer substrate is conducted, the cycles of the atomic layer deposition process are performed.

16 . The method of claim 15 , wherein the functional group is formed on the portion of the internal surfaces of the pores.

17 . The method of claim 15 , wherein the functional group is formed by allowing at least one of water, oxygen, ozone, hydrogen, hydrogen peroxide, alcohol, NO 2 , N 2 O, NH 3 , N 2 , N 2 H 4 , C 2 H 4 , HCOOH, CH 3 COOH, H 2 S, (C 2 H 5 ) 2 S 2 , or CO 2 to react with the portion of the internal surfaces of the pores, using an ultraviolet ray (UV) irradiation treatment or a plasma treatment.

18 . The method of claim 15 , wherein the preprocessing process is performed by adjusting at least one of processing strength, processing time, and the number of times of processing.

Assignees

• Sk Innovation Co Ltd

Inventors

• Kim Hye Jin
• Kwack Won Sub
• Park Min Sang

Classifications

• H01M2200/10

  Temperature sensitive devices · CPC title

• C23C16/45555

  applied in non-semiconductor technology · CPC title

• C23C16/45527

  characterized by the ALD cycle, e.g. different flows or temperatures during half-reactions, unusual pulsing sequence, use of precursor mixtures or auxiliary reactants or activations · CPC title

• C23C16/403

  of aluminium, magnesium or beryllium · CPC title

• C23C16/0245 Primary

  by etching with a plasma · CPC title