Separator for Electrochemical Device and Electrochemical Device Comprising the Same

Patent metadata

Field	Value
Publication number	US-2024258644-A1
Application number	US-202218290579-A
Country	US
Kind code	A1
Filing date	Jul 20, 2022
Priority date	Jul 20, 2021
Publication date	Aug 1, 2024
Grant date	—

Abstract

The present disclosure relates to a separator for an electrochemical device comprising an inorganics-containing porous layer on at least one surface of a porous polymer support, and comprising inorganic fillers and a binder polymer, wherein the binder polymer comprises a first binder polymer, and the first binder polymer is poly(vinylidene fluoride-co-hexafluoropropylene) having a tan δ peak at −18° C. to −5° C. when measured by Dynamic Mechanical Analysis, and an electrochemical device comprising the same. The separator for an electrochemical device according to an embodiment of the present disclosure has improved adhesion property with electrode and safety at high temperature.

First claim

1 . A separator for an electrochemical device, comprising:
a porous polymer support; and an inorganics-containing porous layer on at least one surface of the porous polymer support, and comprising inorganic fillers and a binder polymer, wherein the binder polymer comprises a first binder polymer, and wherein the first binder polymer is poly(vinylidene fluoride-co-hexafluoropropylene) having a tan δ peak at from −18° C. to −5° C. when measured by Dynamic Mechanical Analysis.

2 . The separator for an electrochemical device according to claim 1 , wherein an amount of hexafluoropropylene repeating units in the first binder polymer is from 4 weight % to 22 weight % based on 100 weight % of a sum of an amount of vinylidene fluoride repeating units and the amount of hexafluoropropylene repeating units.

3 . The separator for an electrochemical device according to claim 1 , wherein the binder polymer further comprises a second binder polymer, and
wherein the second binder polymer is poly(vinylidene fluoride-co-chlorotrifluoroethylene) having a tan δ peak at from −11° C. to 0° C. when measured by the Dynamic Mechanical Analysis.

4 . The separator for an electrochemical device according to claim 3 , wherein the second binder polymer has a melting temperature of 155° C. or more.

5 . The separator for an electrochemical device according to claim 3 , wherein an amount of chlorotrifluoroethylene repeating units in the second binder polymer is from 10 weight % to 30 weight % based on 100 weight % of a sum of an amount of vinylidene fluoride repeating units and the amount of chlorotrifluoroethylene repeating units.

6 . The separator for an electrochemical device according to claim 3 , wherein a weight ratio between the first binder polymer and the second binder polymer is 50:50 to 95:5.

7 . The separator for an electrochemical device according to claim 1 , wherein a thickness of the inorganics-containing porous layer is 10 μm or less.

8 . The separator for an electrochemical device according to claim 1 , wherein thermal shrinkage in each of Machine Direction (MD) and Transverse Direction (TD) after leaving the separator for an electrochemical device untouched at 130° C. for 1 hour is 25% or less.

9 . The separator for an electrochemical device according to claim 1 , wherein thermal shrinkage in each of Machine Direction (MD) and Transverse Direction (TD) after leaving the separator for an electrochemical device untouched at 150° C. for 30 minutes is 55% or less.

10 . The separator for an electrochemical device according to claim 1 , wherein the separator for an electrochemical device has an electrode adhesion property of 40 gf/25 mm or more.

11 . The separator for an electrochemical device according to claim 1 , wherein the first binder polymer is poly(vinylidene fluoride-co-hexafluoropropylene) having a γ-crystal form.

12 . The separator for an electrochemical device according to claim 1 , wherein the first binder polymer has a melting temperature of 155° C. or more.

13 . An electrochemical device, comprising:
a positive electrode and a negative electrode, and a separator for an electrochemical device interposed between the positive electrode and the negative electrode, wherein the separator for an electrochemical device is defined in claim 1 .

Assignees

• Lg Chemical Ltd

Inventors

• Kim Bong-Tae
• Lee Joo-Sung
• Mun Sung Cik
• Lee A-Young
• Jung Kil-An
• Han Sung-Jae

Classifications

• H01M50/451

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

• H01M50/457

  comprising three or more layers · CPC title

• H01M50/417

  Polyolefins · CPC title

• H01M50/443

  Particulate material · CPC title

• H01M50/446

  Composite material consisting of a mixture of organic and inorganic materials · CPC title