Separator for electrochemical device, manufacturing method therefor, and electrochemical device including same

Patent metadata

Field	Value
Publication number	US-2025105444-A1
Application number	US-202318708258-A
Country	US
Kind code	A1
Filing date	Jan 13, 2023
Priority date	Feb 14, 2022
Publication date	Mar 27, 2025
Grant date	—

Abstract

Disclosed is a separator for an electrochemical device capable of securing peel strength between a porous polymer substrate and an organic and inorganic composite porous layer and having excellent heat resistance. A manufacturing method thereof and an electrochemical device equipped with the separator are also disclosed. The separator according to one embodiment includes a porous polymer substrate and an organic and inorganic composite porous layer on at least one surface of the porous polymer substrate. The organic and inorganic composite porous layer includes inorganic particles and a particulate acrylic binder polymer, in which the particulate acrylic binder polymer has a crosslinked structure mediated by a benzophenone functional group.

First claim

1 - 28 . (canceled)

29 . A separator for an electrochemical device, the separator comprising:
a porous polymer substrate; and an organic and inorganic composite porous layer on at least one surface of the porous polymer substrate and comprising inorganic particles and a particulate acrylic binder polymer, wherein the particulate acrylic binder polymer has a crosslinked structure mediated by a benzophenone functional group.

30 . The separator of claim 29 , wherein the particulate acrylic binder polymer comprises an acrylic monomer unit containing a benzophenone functional group.

31 . The separator of claim 30 , wherein the particulate acrylic binder polymer further comprises one or more selected from the group consisting of a branched or non-branched (meth)acrylic acid monomer unit having 1 to 20 carbon atoms, a branched or non-branched (meth)acrylate monomer unit having 1 to 20 carbon atoms, an acrylonitrile monomer unit, a vinyl pyrrolidone monomer unit, and a vinyl acetate monomer unit.

32 . The separator of claim 29 , wherein the particulate acrylic binder polymer has a structure represented by the following Formula 1:

wherein, in Formula 1, m, n, o, and p are each an integer of 1 or greater.

33 . The separator of claim 29 , wherein the particulate acrylic binder polymer has a storage modulus at 50° C. in a range of 20,000 Pa to 300,000 Pa.

34 . The separator of claim 29 , wherein the particulate acrylic binder polymer has a glass transition temperature in a range of −70° C. to 70° C., and
wherein the particulate acrylic binder polymer has a gel fraction in a range of 10% to 90%.

35 . The separator of claim 29 , wherein the particulate acrylic binder polymer has an average particle diameter (D50) in a range of 0.001 μm to 10 μm, and
wherein the inorganic particle has an average particle diameter (D50) in a range of 0.1 μm to 2.0 μm.

36 . The separator of claim 29 , wherein the organic and inorganic composite porous layer further comprises a non-particulate binder polymer.

37 . The separator of claim 36 , wherein the non-particulate binder polymer comprises one or more selected from the group consisting of carboxy methyl cellulose, polyacrylic acid, and polyacrylamide.

38 . The separator of claim 36 , wherein a weight ratio of the inorganic particles and the particulate acrylic binder polymer is in a range of 99.9:0.1 to 70:30, and
wherein a weight ratio of the particulate acrylic binder polymer and the non-particulate binder polymer is in a range of 5:95 to 95:5.

39 . The separator of claim 29 , wherein a heat shrinkage rate after the separator is left at 135° C. for 30 minutes is 10% or less in a machine direction (MD) and 10% or less in a transverse direction (TD), and
wherein a peel strength between the porous polymer substrate and the organic and inorganic composite porous layer is in a range of 5 gf/15 mm to 1000 gf/15 mm.

40 . A method of manufacturing a separator for an electrochemical device, the method comprising:
preparing a slurry for forming an organic and inorganic composite porous layer comprising inorganic particles and a non-crosslinked particulate acrylic binder polymer comprising a benzophenone functional group; applying and drying the slurry on at least one surface of a porous polymer substrate; and irradiating with ultraviolet rays.

41 . The method of claim 40 , wherein the non-crosslinked particulate acrylic binder polymer comprises a first acrylic monomer unit and a second acrylic monomer unit, and
wherein the first acrylic monomer unit comprises one or more selected from the group consisting of benzophenone methacrylate unit, 6-(4-benzoylphenoxy)hexyl methacrylate unit, and benzophenone acrylate unit.

42 . The method of claim 41 , wherein the second acrylic monomer unit comprises (a) a branched or non-branched (meth)acrylic acid monomer unit having 1 to 20 carbon atoms, a branched or (b) a non-branched (meth)acrylate monomer unit having 1 to 20 carbon atoms, and one or more selected from the group consisting of an acrylonitrile monomer unit, a vinyl pyrrolidone monomer unit, and a vinyl acetate monomer unit.

43 . The method of claim 40 , wherein non-crosslinked particulate acrylic binder polymer comprises a copolymer represented by the following Formula 2:

wherein in Formula 2, m, n, o, and p are each an integer of 1 or greater.

44 . The method of claim 41 , wherein a content of the first acrylic monomer unit is 500 ppm to 20,000 ppm based on a weight of the second acrylic monomer unit.

45 . The method of claim 40 , wherein the non-crosslinked particulate acrylic binder polymer has a storage modulus at 50° C. before the irradiation with ultraviolet rays in a range of 10,000 Pa to 80,000 Pa.

46 . The method of claim 40 , wherein a change rate of a storage modulus of the particulate acrylic binder polymer at 50° C. before irradiation with ultraviolet rays and the storage modulus of the particulate acrylic binder polymer after irradiation with ultraviolet rays is in a range of 20% to 300%.

47 . The method of claim 40 , wherein an irradiation amount of the ultraviolet rays is in a range of 0.1 J to 10 J,
wherein a wavelength of the ultraviolet rays is in a range of 200 nm to 400 nm, and wherein a wavelength of the ultraviolet rays is in a range of 230 nm to 350 nm.

48 . An electrochemical device comprising a cathode, an anode, and a separator between the cathode and the anode,
wherein the separator is the separator of claim 29 .

Assignees

• Lg Energy Solution Ltd

Inventors

• Shin Hwan Ho
• Bae Dong Hun
• Kim Ji Eun
• Sung Dong Wook

Classifications

• C08F2800/20

  as weight or mass percentages · CPC title

• C08F220/12

  of monohydric alcohols or phenols · CPC title

• H01M50/434

  Ceramics · CPC title

• H01M50/451

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

• H01M50/443

  Particulate material · CPC title