# US 12,119,515 B2 · Separator for an electrochemical device including a porous organic/inorganic composite coating layer and an electrochemical device including same

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- Number: US 12,119,515 B2
- Document ID: US12119515B2
- Status: Granted
- Kind: B2
- Application number: 18/647,536
- Filed: 2024-04-26
- Published: 2024-08-15
- Granted: 2024-10-15
- Earliest claimed: 2022-05-26
- Assignees: LG Energy Solution, Ltd.
- Applicants: LG Energy Solution, Ltd.
- Inventors: Kyung-Ryun Ka; Min-Ji Kim; Seung-Hyun Lee; Hye-Won Kim
- Web page: https://patentgrep.com/patent/US12119515B2

## CPC

- H01M 50/446: Composite material consisting of a mixture of organic and inorganic materials
- H01M 10/052: Li-accumulators
- H01M 50/42: Acrylic resins
- H01M 50/426: Fluorocarbon polymers
- H01M 50/434: Ceramics
- H01M 50/443: Particulate material
- H01M 50/449: having a layered structure
- H01M 50/451: comprising layers of only organic material and layers containing inorganic material
- H01M 50/491: Porosity
- Y02E 60/10: Energy storage using batteries
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

Disclosed is a separator suitable for an electrochemical device a porous including polymer substrate and an organic/inorganic composite porous coating layer on at least one side of the porous polymer substrate. The organic/inorganic composite porous coating layer includes particulate binder polymers and first inorganic particles, the particulate binder polymers include (a) hybrid polymer particles of a fluorine-containing polymer and an acrylic-containing polymer and (b) acrylic-containing polymer particles, the average particle diameter D50 of the acrylic-containing polymer particles “a” is in a range of 1 μm to 7.5 μm, the average particle diameter D50 of the inorganic particles “b” is in a range of 200 nm to 800 nm, a/b is in a range of 2 to 15, and the average particle diameter D50 of the hybrid polymer particles is smaller than the average particle diameter D50 of the acrylic-containing polymer particles.

## Claims

### Claim 1

An electrochemical device separator comprising
a porous polymer substrate; and
an organic/inorganic composite porous coating layer on at least one side of the porous polymer substrate, said organic/inorganic composite porous coating layer comprising particulate binder polymers, first inorganic particles and second inorganic particles, which second inorganic particles are different from the first inorganic particles,
wherein the particulate binder polymers comprise:
(a) hybrid polymer particles comprising a fluorine-containing polymer and an acrylic-containing polymer; and
(b) acrylic-containing polymer particles, wherein the acrylic-containing polymer particles have an average particle diameter D50 “a” in a range of 1 μm to 7.5 μm,
the first inorganic particles have an average particle diameter D50 “b” in a range of 200 nm to 800 nm,
a/b is in a range of 2 to 15,
the hybrid polymer particles have an average particle diameter D50 smaller than the average particle diameter D50 of the acrylic-containing polymer particles, and
the second inorganic particles have an average particle diameter D50 smaller than or equal to the average particle diameter D50 of the first inorganic particles.

### Claim 2 (depends on 1)

The electrochemical device separator of claim 1, wherein the acrylic-containing polymer particles have an average particle diameter D50 “a” in a range of 2 μm to 6 μm, and the first inorganic particles have an average particle diameter D50 “b” in a range of 300 nm to 700 nm, and a/b is in a range of 5 to 12.

### Claim 3 (depends on 1)

The electrochemical device separator of claim 1, wherein the acrylic-containing polymer particles have an average particle diameter D50 that is 4 to 20 times larger than an average particle diameter D50 of the hybrid polymer particles.

### Claim 4 (depends on 1)

The electrochemical device separator of claim 1, wherein the hybrid polymer particles have an average particle diameter D50 in a range of 100 nm to 500 nm.

### Claim 5 (depends on 1)

The electrochemical device separator of claim 1, wherein the hybrid polymer particles and the acrylic-containing polymer particles are present as a mixture in a weight ratio of 8:2 to 2:8.

### Claim 6 (depends on 1)

The electrochemical device separator of claim 1, wherein the acrylic-containing polymer present in the hybrid polymer particles has a glass transition temperature Tg that is lower, by 10° C. or more, than a Tg of the acrylic-containing polymer present in the acrylic-containing polymer particles.

### Claim 7 (depends on 6)

The electrochemical device separator of claim 6, wherein the Tg of the acrylic-containing polymer present in the hybrid polymer particles is in a range of 10° C. to 30° C., and the Tg of the acrylic-containing polymer present in the acrylic-containing polymer particles is in a range of 30° ° C. to 50° C.

### Claim 8 (depends on 1)

The electrochemical device separator of claim 1, wherein the fluorine-containing polymer comprises one or more selected from the group consisting of a homopolymer of vinylidene fluoride, and a copolymer of vinylidene fluoride and another polymerizable monomer.

### Claim 9 (depends on 8)

The electrochemical device separator of claim 8, wherein the another polymerizable monomer comprises at least one selected from the group consisting of tetrafluoroethylene, hexafluoropropylene, trifluoroethylene, chlorofluoroethylene, 1,2-difluoroethylene, perfluoro(methylvinyl) ether, perfluoro (ethylvinyl) ether, perfluoro (propylvinyl) ether, perfluoro (1,3 dioxole), perfluoro (2,2-dimethyl-1,3-dioxole), trichloroethylene, and vinyl fluoride.

### Claim 10 (depends on 8)

The electrochemical device separator of claim 8, wherein the fluorine-containing polymer is a copolymer of vinylidene fluoride and hexafluoropropylene.

### Claim 11 (depends on 8)

The electrochemical device separator of claim 8, wherein a content of the other polymerizable monomer is 1% to 20% by weight of the copolymer of vinylidene fluoride and the another polymerizable monomer.

### Claim 12 (depends on 1)

The electrochemical device separator of claim 1, wherein the acrylic-containing polymer present in the hybrid polymer particles and the acrylic-containing polymer present in the acrylic-containing polymer particles each independently comprise an alkyl (meth)acrylate repeating unit having an alkyl group having 1 to 18 carbon atoms.

### Claim 13 (depends on 1)

The electrochemical device separator of claim 1, wherein the organic/inorganic composite porous coating layer further comprises a non-particulate acrylic-containing polymer.

### Claim 14 (depends on 13)

The electrochemical device separator of claim 13, wherein the non-particulate acrylic-containing polymer has a glass transition temperature Tg of 0° C. or less.

### Claim 15 (depends on 1)

The electrochemical device separator of claim 1, wherein the second inorganic particles have an average particle diameter D50 in a range of 100 nm to 500 nm.

### Claim 16 (depends on 1)

The electrochemical device separator of claim 1, wherein the first inorganic particles comprise alumina and the second inorganic particles comprise boehmite.

### Claim 17 (depends on 1)

The electrochemical device separator of claim 1, wherein the organic/inorganic composite porous coating layer comprises the particulate binder polymers in an amount of 1% to 30% by weight based on a total weight of the organic/inorganic composite porous coating layer.

### Claim 18 (depends on 1)

The electrochemical device separator of claim 1, wherein the organic/inorganic composite porous coating layer is formed by coating and drying a slurry, and
the particulate binder polymers and inorganic particles are dispersed in an aqueous dispersion medium on the at least one side of the porous polymer substrate.

### Claim 19 (depends on 1)

An electrochemical device comprising:
an anode, a cathode, and the electrochemical device separator according to claim 1 interposed between the anode and the cathode.

### Claim 20 (depends on 19)

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