Separator for rechargeable battery and rechargeable lithium battery including the same

Patent metadata

Field	Value
Publication number	US-2018337381-A1
Application number	US-201815982380-A
Country	US
Kind code	A1
Filing date	May 17, 2018
Priority date	May 17, 2016
Publication date	Nov 22, 2018
Grant date	—

Abstract

Disclosed are a separator for a rechargeable battery including a porous substrate and a heat resistance layer on at least one surface of the porous substrate, wherein the heat resistance layer includes an acryl-based heat resistance binder, a water-soluble binder, and a filler, and the acryl-based heat resistance binder includes a structural unit derived from (meth)acrylate or (meth)acrylic acid, a cyano group-containing structural unit and a sulfonate group-containing structural unit, and a rechargeable lithium battery including the same.

First claim

What is claimed is:

1 . A separator for a rechargeable battery comprising
a porous substrate and a heat resistance layer on at least one surface of the porous substrate, wherein the heat resistance layer includes an acryl-based heat resistance binder, a water-soluble binder, and a filler, and the acryl-based heat resistance binder includes a structural unit derived from (meth)acrylate or (meth)acrylic acid, a cyano group-containing structural unit, and a sulfonate group-containing structural unit.

2 . The separator for a rechargeable battery as claimed in claim 1 , wherein the water-soluble binder is a binder including at least one functional group selected from a hydroxyl group or a carboxyl group.

3 . The separator for a rechargeable battery as claimed in claim 1 , wherein the a structural unit derived from (meth)acrylate or (meth)acrylic acid is represented by Chemical Formula 1, Chemical Formula 2, Chemical Formula 3, or a combination thereof:

wherein, in Chemical Formula 1 to Chemical Formula 3,
R 1 , R 2 and R 3 are independently hydrogen or a methyl group, and
in Chemical Formula 2,
M is an alkali metal.

4 . The separator for a rechargeable battery as claimed in claim 1 , wherein the cyano group-containing structural unit is represented by Chemical Formula 4:

wherein, in Chemical Formula 4,
R 4 is hydrogen or a C1 to C3 alkyl group, L 1 is —C(═O)—, —C(═O)O—, —OC(═O)—, —O—, or —C(═O)NH—,
x is an integer ranging from 0 to 2,
L 2 is a substituted or unsubstituted C1 to C10 alkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, or a substituted or unsubstituted C3 to C20 heterocyclic group, and
y is an integer ranging from 0 to 2.

5 . The separator for a rechargeable battery as claimed in claim 1 , wherein the sulfonate group-containing structural unit is represented by Chemical Formula 5, Chemical Formula 6, Chemical Formula 7, or a combination thereof:

wherein, in Chemical Formula 5 to Chemical Formula 7,
R 5 , R 6 , and R 7 are independently hydrogen or a C1 to C3 alkyl group,
L 3 , L 5 , and L 7 are independently —C(═O)—, —C(═O)O—, —OC(═O)—, —O—, or —C(═O)NH—,
L 4 , L 6 , and L 8 are independently a substituted or unsubstituted C1 to C10 alkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, or a substituted or unsubstituted C3 to C20 heterocyclic group, and
a, b, c, d, e, and f are independently an integer ranging from 0 to 2,
in Chemical Formula 6,
M′ is an alkali metal.

6 . The separator for a rechargeable battery as claimed in claim 1 , wherein a weight average molecular weight of the acryl-based heat resistance binder ranges from 200,000 g/mol to 700,000 g/mol.

7 . The separator for a rechargeable battery as claimed in claim 1 , wherein a glass transition temperature of the acryl-based heat resistance binder ranges from 200° C. to 280° C.

8 . The separator for a rechargeable battery as claimed in claim 1 , wherein the acryl-based heat resistance binder includes an alkali metal.

9 . The separator for a rechargeable battery as claimed in claim 1 , wherein the acryl-based heat resistance binder and the water-soluble binder are included in a weight ratio of 2:8 to 8:2.

10 . The separator for a rechargeable battery as claimed in claim 1 , wherein the water-soluble binder is a cellulose-based binder.

11 . The separator for a rechargeable battery as claimed in claim 10 , wherein the cellulose-based binder is represented by Chemical Formula 9.

wherein, in Chemical Formula 9,
R's are independently —OH or R′COOH, and
R′ is a substituted or unsubstituted C1 to C10 alkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group or a substituted or unsubstituted C3 to C20 heterocyclic group.

12 . The separator for a rechargeable battery as claimed in claim 11 , wherein the cellulose-based binder is selected from carboxyl methyl cellulose, hydroxypropyl cellulose, and diacetyl cellulose, or a combination thereof.

13 . The separator for a rechargeable battery as claimed in claim 1 , wherein a weight average molecular weight of the water-soluble binder ranges from 50,000 g/mol to 800,000 g/mol.

14 . A rechargeable lithium battery comprising
a positive electrode, a negative electrode, and the separator as claimed in claim 1 disposed between the positive electrode and the negative electrode.

Assignees

• Samsung Sdi Co Ltd

Inventors

• Seo Dongwan
• Choi Hyeonsun
• Park Jinkyu

Classifications

• C08F220/48 Primary

  with nitrogen-containing monomers · CPC title

• H01M50/411

  Organic material · CPC title

• H01M50/449

  having a layered structure · CPC title

• H01M10/052

  Li-accumulators · CPC title

• C08J7/0427

  with only one layer of a composition containing a polymer binder (with more layers C08J7/042) · CPC title