Separator and secondary battery using same

Patent metadata

Field	Value
Publication number	US-2016293923-A1
Application number	US-201415038306-A
Country	US
Kind code	A1
Filing date	Nov 20, 2014
Priority date	Nov 21, 2013
Publication date	Oct 6, 2016
Grant date	—

Abstract

The present invention relates to a separator comprising a porous substrate and an adhesive layer on one surface or both surfaces of the porous substrate, wherein the adhesive layer includes an acryl-based copolymer containing a (meth)acrylate-based monomer-derived repeating unit and having a weight average molecular weight of 400,000 g/mol to 750,000 g/mol; and to a secondary battery comprising the separator.

First claim

What is claimed is:

1 . A separator comprising a porous substrate and an adhesive layer on one surface or both surfaces of the porous substrate and including an acryl-based copolymer containing a (meth)acrylate-based monomer-derived repeating unit and having a weight average molecular weight of 400,000 g/mol to 750,000 g/mol.

2 . The separator of claim 1 , wherein the acryl-based copolymer further comprises an acetate group-containing monomer-derived repeating unit.

3 . The separator of claim 2 , wherein the acetate group-containing monomer-derived repeating unit is a repeating unit derived from at least one monomer of vinyl acetate and allyl acetate.

4 . The separator of claim 1 , wherein the (meth)acrylate-based monomer-derived repeating unit is a repeating unit derived from at least one a repeating unit selected from the group consisting of butyl (meth)acrylate, propyl (meth)acrylate, ethyl (meth)acrylate, and methyl (meth)acrylate.

5 . The separator of claim 1 , wherein the acryl-based copolymer is prepared by a polymerization reaction of a butyl (meth)acrylate monomer, methyl (meth)acrylate monomer and vinyl acetate and/or allyl acetate monomer, in a mole ratio of 3 to 5:0.5 to 1.5:3.0 to 6.5.

6 . The separator of claim 1 , wherein the adhesive layer further comprises an inorganic particle.

7 . The separator of claim 1 , wherein the adhesive layer further comprises a polyvinylidene fluoride-based polymer.

8 . The separator of claim 7 , wherein the polyvinylidene fluoride-based polymer is a polyvinylidene fluoride-hexafluoropropylene copolymer or a polyvinylidene fluoride homopolymer.

9 . The separator of claim 7 , wherein a weight ratio of the acryl-based copolymer and the polyvinylidene fluoride-based polymer is 9.9:0.1 to 2.5:7.5.

10 . The separator of claim 7 , wherein a weight average molecular weight of the polyvinylidene fluoride-based polymer is 1,000,000 g/mol to 1,500,000 g/mol.

11 . The separator of claim 1 , wherein the porous substrate is a porous polyolefin-based substrate.

12 . A separator comprising a porous substrate, and a binder-containing adhesive layer on one surface or both surfaces of the porous substrate, wherein a transfer rate of a negative active material to the separator according to Equation 1 after charge and discharge is greater than or equal to 60%:
Transfer rate(%)=( A 1 /A 0 )×100   [Equation 1]
wherein in Equation 1, A 0 is a total area of a negative electrode, and A 1 is an area of a negative active material transferred to a separator when charge, discharge, and charge are sequentially performed after a positive electrode, a separator, and a negative electrode are sequentially stacked to form an electrode assembly, first compressing the electrode assembly at 20° C. to 110° C., for 1 second to 5 seconds, and at a force of 1 kgf/cm 2 to 30 kgf/cm 2 , injecting an electrolyte solution to the compressed electrode assembly, and second compressing the same at 60° C. to 110° C., for 30 seconds to 180 seconds, at a force of 1 kgf/cm 2 to 30 kgf/cm 2 .

13 . The separator of claim 12 , wherein the adhesive layer comprises an acryl-based copolymer containing a (meth)acrylate-based monomer-derived repeating unit and having a weight average molecular weight of 400,000 g/mol to 750,000 g/mol.

14 . The separator of claim 13 , wherein the acryl-based copolymer further comprises an acetate group-containing monomer-derived repeating unit.

15 . The separator of claim 12 , wherein the adhesive layer further comprises an inorganic particle.

16 . The separator of claim 12 , wherein the adhesive layer further comprises a polyvinylidene fluoride-based polymer.

17 . The separator of claim 12 , wherein the porous substrate is a porous polyolefin-based substrate.

18 . A secondary battery comprising a positive electrode; a negative electrode; the separator of claim 1 between the positive electrode and the negative electrode; and an electrolyte solution.

19 . The secondary battery of claim 18 , wherein the secondary battery is a lithium secondary battery.

Assignees

• Samsung Sdi Co Ltd

Inventors

• Kim Nam Hyo
• Kim Kee Wook
• Kim Yang Seob
• Yun Hyo Sang
• Lee Yong Bae
• Lee Jung Min
• Lee Jung Yoon
• Chun Ji Hyun

Classifications

• C09D127/16

  Homopolymers or copolymers of vinylidene fluoride · CPC title

• C09J131/04

  Homopolymers or copolymers of vinyl acetate · CPC title

• H01M4/587

  for inserting or intercalating light metals · CPC title

• H01M4/133

  Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx · CPC title

• H01M4/623

  fluorinated polymers · CPC title