Separator for Electrochemical Device and Electrochemical Device Including the Same

Patent metadata

Field	Value
Publication number	US-2025112330-A1
Application number	US-202318833055-A
Country	US
Kind code	A1
Filing date	Jan 26, 2023
Priority date	Jan 26, 2022
Publication date	Apr 3, 2025
Grant date	—

Abstract

A separator for an electrochemical device; includes a polymer porous support and an inorganic composite porous layer formed on at least one surface of the porous support. The inorganic composite porous layer includes a binder polymer and an inorganic filler, the binder polymer includes an amorphous polymer having a glass transition temperature (Tg) of 180° C. or higher, the content of the inorganic filler is 30-200 parts by weight based on 100 parts by weight of the binder polymer, and the separator shows a dielectric breakdown voltage of 2 kV or more. The separator for an electrochemical device provides an electrochemical device with improved voltage resistance characteristics to realize a high dielectric breakdown voltage, and can provide a reduced short-circuit generation ratio (defect rate in a Hi-Pot test) even under a high voltage condition. An electrochemical device including the separator is also provided.

First claim

1 . A separator for an electrochemical device, comprising:
a polymer porous support; and an inorganic composite porous layer formed on at least one surface of the porous support, wherein the inorganic composite porous layer comprises a binder polymer and an inorganic filler, the binder polymer comprises an amorphous polymer having a glass transition temperature (Tg) of 180° C. or higher, a content of the inorganic filler ranges from 30 to 200 parts by weight based on 100 parts by weight of the binder polymer, and the separator has a dielectric breakdown voltage of 2 kV or more.

2 . The separator of claim 1 , wherein the separator has a dielectric breakdown voltage ranging from 2 kV to −6 kV.

3 . The separator of claim 1 , wherein the separator has a dielectric breakdown strength of 4.5 kV/milli-inch or more.

4 . The separator of claim 1 , wherein the separator has a total thickness ranging from 5_to 20 μm.

5 . The separator of claim 1 , wherein the amorphous polymer has the glass transition temperature (Tg) of 180° C. or higher includes one or more of polyimide (PI), polyamideimide (PAI), polyetherimide (PEI), polyphenylsulfone (PPSU), polyethersulfone (PES), or_polysulfone (PSU).

6 . The separator of claim 1 , wherein the binder polymer consists of the amorphous polymer having the glass transition temperature (Tg) of 180° C. or higher.

7 . The separator of claim 1 , wherein the content of the inorganic filler ranges from 40 to 185 parts by weight based on 100 parts by weight of the binder polymer.

8 . The separator of claim 1 , wherein the inorganic filler has an average particle diameter ranging from 20 nm to −700 nm.

9 . An electrochemical device, comprising:
a positive electrode; a negative electrode; and the separator of claim 1 interposed between the positive electrode and the negative electrode.

10 . The electrochemical device of claim 9 , wherein the electrochemical device is a lithium secondary battery.

11 . A method for manufacturing the separator of claim 1 , comprising:
preparing the polymer porous support; applying a slurry including the amorphous polymer having the glass transition temperature of 180° C. or higher, the inorganic filler, and a solvent to the at least one surface of the polymer porous support; and dipping the polymer porous support coated with the slurry in a composition including a non-solvent for the amorphous polymer, followed by drying, so as to form the inorganic composite porous layer.

12 . The method of claim 11 , wherein the non-solvent comprises one or more of water, methanol, ethanol, propyl alcohol, butyl alcohol, butanediol, ethylene glycol, propylene glycol, tripropylene glycol, acetone, tetrahydrofuran, methylene chloride, chloroform, dimethyl acetamide, dimethyl formamide, N-methyl-2-pyrrolidone, cyclohexane, or isopropyl alcohol.

Assignees

• Lg Chemical Ltd

Inventors

• Lee A-Young
• Lee Joo-Sung

Classifications

• H01M10/052

  Li-accumulators · CPC title

• H01M50/431

  Inorganic material · CPC title

• H01M50/403

  Manufacturing processes of separators, membranes or diaphragms · CPC title

• H01M50/414

  Synthetic resins, e.g. thermoplastics or thermosetting resins · CPC title

• H01M50/497

  Ionic conductivity · CPC title