Separator for electrochemical device, electrochemical device comprising the same and manufacturing method of the separator

Patent metadata

Field	Value
Publication number	US-12126045-B2
Application number	US-201916633376-A
Country	US
Kind code	B2
Filing date	Jun 21, 2019
Priority date	Jun 22, 2018
Publication date	Oct 22, 2024
Grant date	Oct 22, 2024

Abstract

Provided is a separator for an electrochemical device, including: a porous polymer substrate; and a porous organic/inorganic coating layer formed on at least one surface of the porous polymer substrate and including heat conductive inorganic particles and core-shell particles, wherein the particles are bound to one another by a binder polymer, and wherein the core-shell particle includes a core portion and a shell portion surrounding the surface of the core portion, the core portion includes a metal hydroxide having heat-absorbing property at 150-400° C., the shell portion includes a polymer resin, and the polymer resin is a water-insoluble polymer or crosslinked polymer. An electrochemical device including the separator is also provided. It is possible to provide a separator with an improved heat-absorbing effect and safety, and an electrochemical device including the same.

First claim

What is claimed is:

1. A separator for an electrochemical device, comprising:
a porous polymer substrate; and
a porous organic/inorganic coating layer formed on at least one surface of the porous polymer substrate and comprising a heat conductive inorganic particle and a core-shell particle, wherein the particles are bound to one another by a binder polymer, and
wherein the core-shell particle comprises a core portion and a shell portion surrounding a surface of the core portion, the core portion comprises a metal hydroxide having heat-absorbing property at 150° C. to 400° C., wherein the shell portion is configured to prevent outflow of water caused by decomposing of the core portion into a metal oxide and water, and wherein the shell portion comprises a polymer resin, and the polymer resin is a water-insoluble polymer or crosslinked polymer,
wherein the crosslinked polymer comprises a carboxyl group, hydroxyl group, isocyanate group, methylol group, amine group, cyanoethyl group, or a mixture of two or more thereof, as a functional group, in its backbone,
wherein the heat conductive inorganic particle has a heat conductivity of 20 W/mK to 350 W/m·K,
wherein the porous organic/inorganic coating layer further comprises a heat-absorbing organic particle, and
wherein the organic/inorganic porous coating layer has a multilayer structure comprising:
a first porous organic/inorganic coating layer including the heat-absorbing organic particle and the heat conductive inorganic particle formed on a surface of the porous polymer substrate, and a second porous organic/inorganic coating layer formed on a surface of the first porous organic/inorganic coating layer and including the core-shell particle,

wherein the first porous organic/inorganic coating layer and the second porous organic/inorganic coating layer are not identical.

2. The separator according to claim 1 , wherein the heat conductive inorganic particle comprises alumina, magnesium oxide, zinc oxide, aluminum nitride, boron nitride, or a mixture of two or more thereof.

3. The separator according to claim 1 , wherein the core-shell particle has a diameter of 50 nm to 900 nm, and the shell portion has a thickness of 1 nm to 20 nm.

4. The separator according to claim 1 , wherein the metal hydroxide is a hydroxide containing at least one element selected from the group consisting of aluminum, magnesium, silicon, zirconium, calcium, strontium, barium, antimony, tin, zinc and rare earth elements.

5. The separator according to claim 1 , wherein the shell portion comprises the water-insoluble polymer comprises styrene butadiene rubber (SBR), acrylonitrile-butadiene rubber, acrylonitrile-butadiene-styrene rubber, acrylic copolymer, polyacrylonitrile, polyvinyl chloride, polyvinylidene fluoride, styrene, polycyanoacrylate, or a mixture of two or more thereof.

6. The separator according to claim 1 , wherein the shell portion comprises the crosslinked polymer, and the crosslinked polymer comprises cyanoethylpolyvinylalcohol.

7. The separator according to claim 1 , wherein the core-shell particle comprises the shell portion in an amount of 0.5 parts to 3 parts by weight based on 100 parts by weight of the core portion.

8. The separator according to claim 1 , wherein the core-shell particle is present in an amount of 30 parts to 90 parts by weight of the heat conductive inorganic particle.

9. The separator according to claim 1 , wherein the heat-absorbing organic particle is a polymer having a melting point of 100° C. to 150° C.

10. The separator according to claim 1 , wherein the heat-absorbing organic particle comprises polyethylene, polypropylene, polyvinylidene fluoride, polyvinylidene fluoride copolymer, or a mixture of two or more thereof.

11. The separator according to claim 1 , wherein the heat-absorbing organic particle is present in an amount of 10 parts to 80 parts by weight based on 100 parts by weight of the heat conductive inorganic particle.

12. An electrochemical device comprising a cathode, an anode and the separator as defined in claim 1 .

13. A method for manufacturing a separator for an electrochemical device, comprising:
preparing a porous polymer substrate; and
forming a porous organic/inorganic coating layer on at least one surface of the porous polymer substrate, wherein the porous organic/inorganic coating layer comprises heat conductive inorganic particle and core-shell particle, and the heat conductive inorganic particle and the core-shell particle are bound to one another by a binder polymer, and
wherein the core-shell particle comprises a core portion and a shell portion surrounding the surface of the core portion, the core portion comprises a metal hydroxide having heat-absorbing property at 150° C. to 400° C., the shell portion comprises a polymer resin, and the polymer resin is a water-insoluble polymer or crosslinked polymer,
wherein the crosslinked polymer comprises a carboxyl group, hydroxyl group, isocyanate group, methylol group, amine group, cyanoethyl group, or a mixture of two or more thereof, as a functional group, in its backbone, and
wherein the porous organic/inorganic coating layer has a multilayer structure comprising:
a first porous organic/inorganic coating layer including the heat-absorbing organic particle and the heat conductive inorganic particle formed on a surface of the porous polymer substrate, and a second porous organic/inorganic coating layer formed on a surface of the first porous organic/inorganic coating layer and including the core-shell particle,

wherein the first porous organic/inorganic coating layer and the second porous organic/inorganic coating layers are not identical.

14. The method according to claim 13 , wherein the forming the porous organic/inorganic coating layer comprises applying a slurry containing core-shell particle, heat conductive inorganic particle, a binder polymer and a solvent to at least one surface of the porous polymer substrate, followed by drying.

15. The method according to claim 13 , wherein the forming the porous organic/inorganic coating layer comprises:
applying a slurry containing core-shell particle, a binder polymer and a solvent to at least one surface of the porous polymer substrate, followed by drying, to form a first porous organic/inorganic coating layer; and applying a slurry containing heat conductive inorganic particle, a binder polymer and a solvent to a surface of the first porous organic/inorganic coating layer, followed by drying, to form a second porous organic/inorganic coating layer; or
applying a slurry containing heat conductive inorganic particle, a binder polymer and the solvent to at least one surface of the porous polymer substrate, followed by drying, to form a first porous organic/inorganic coating layer; and applying a slurry containing core-shell particles, the binder polymer and the solvent to the surface of the first porous organic/inorganic coating layer, followed by drying, to form a second porous organic/inorganic coating layer.

16. The method according to claim 14 , wherein the solvent comprises acetone, tetrahydrofuran, methylene chloride, chloroform, dimethyl formamide, N-methyl- 2-pyrrolidone (NMP), cyclohexane, or a mixture of two or more thereof.

Assignees

• Lg Chemical Ltd

Inventors

• Lee Joo-Sung
• Lee A-Young
• Jin Sun-Mi

Classifications

• H01M50/489

  Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties · CPC title

• H01M50/451 Primary

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

• H01M50/457

  comprising three or more layers · CPC title

• H01M50/42

  Acrylic resins · CPC title

• H01M50/417

  Polyolefins · CPC title