Separator, secondary battery containing such separator, and related battery module, battery pack, and apparatus

Patent metadata

Field	Value
Publication number	US-2023207963-A1
Application number	US-202318114164-A
Country	US
Kind code	A1
Filing date	Feb 24, 2023
Priority date	Nov 30, 2020
Publication date	Jun 29, 2023
Grant date	—

Abstract

This application relates to a separator, including a substrate and a coating layer provided on at least one surface of the substrate. The coating layer includes organic particles and inorganic particles, the organic particles include first-type organic particles, the inorganic particles form an inorganic particle layer, and the first-type organic particles are embedded into the inorganic particle layer and form bulges on a surface of the inorganic particle layer. A number-based median particle size of the first-type organic particles is ≥12 μm, and a ratio of an average height of the bulges to a thickness of the inorganic particle layer is ≥4. This application further relates to a separator preparation method, a secondary battery containing such separator, and a related battery module, battery pack, and apparatus.

First claim

What is claimed is:

1 . A separator, comprising:
a substrate; and a coating layer provided on at least one surface of the substrate; wherein the coating layer comprises organic particles and inorganic particles, the organic particles comprise first-type organic particles, the inorganic particles form an inorganic particle layer, and the first-type organic particles are embedded into the inorganic particle layer and form bulges on a surface of the inorganic particle layer; a number-based median particle size of the first-type organic particles is ≥12 μm; and a ratio of an average height of the bulges to a thickness of the inorganic particle layer is ≥4.

2 . The separator according to claim 1 , wherein the ratio of the average height of the bulges to the thickness of the inorganic particle layer is 4-20.

3 . The separator according to claim 1 , wherein the average height of the bulges is ≥10 μm.

4 . The separator according to claim 1 , wherein the number-based median particle size of the first-type organic particles is 15 μm-25 μm.

5 . The separator according to claim 1 , wherein the first-type organic particles are secondary particles.

6 . The separator according to claim 1 , wherein the first-type organic particles comprise one or more of a homopolymer or copolymer of a fluorinated alkenyl monomer unit, a homopolymer or copolymer of an alkylene monomer unit, a homopolymer or copolymer of an unsaturated nitrile monomer unit, a homopolymer or copolymer of an alkylene oxide monomer unit, and modified compounds of the foregoing homopolymers or copolymers; and
the first-type organic particles comprise one or more of polytetrafluoroethylene, polytrifluorochloroethylene, polyfluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyacrylonitrile, polyethylene oxide, a copolymer of different fluorinated alkenyl monomer units, a copolymer of the fluorinated alkenyl monomer unit and the alkylene monomer unit, a copolymer of the fluorinated alkenyl monomer unit and an acrylic acid monomer unit, a copolymer of the fluorinated alkenyl monomer unit and an acrylic monomer unit, and modified compounds of the foregoing homopolymers or copolymers.

7 . The separator according to claim 1 , wherein the first-type organic particles comprise one or more of a vinylidene fluoride-trifluoroethylene copolymer, a vinylidene fluoride-hexafluoropropylene copolymer, a vinylidene fluoride-trifluoroethylene-hexafluoropropylene copolymer, a vinylidene fluoride-hexafluoropropylene-acrylic acid copolymer, a vinylidene fluoride-hexafluoropropylene-acrylate copolymer, and modified compounds of the foregoing copolymers.

8 . The separator according to claim 1 , wherein the separator satisfies at least one of the following (1) and (2):
(1) a mass ratio of the first-type organic particles to the coating layer is ≥12%; and (2) a mass ratio of the inorganic particles to the coating layer is ≤85%.

9 . The separator according to claim 1 , wherein the organic particles further comprise second-type organic particles, the second-type organic particles are embedded into the inorganic particle layer and form bulges on a surface of the inorganic particle layer, and the second-type organic particles are primary particles.

10 . The separator according to claim 9 , wherein: a number-based median particle size of the second-type organic particles is ≤10 μm and the number-based median particle size of the second-type organic particles is ≥2 μm.

11 . The separator according to claim 9 , wherein a mass ratio of the second-type organic particles to the coating layer is below 10%.

12 . The separator according to claim 9 , wherein: the second-type organic particles comprise one or more of a homopolymer or copolymer of the acrylic monomer unit, a homopolymer or copolymer of the acrylic acid monomer unit, a homopolymer or copolymer of a styrene monomer unit, a polyurethane compound, a rubber compound, and modified compounds of the foregoing homopolymers or copolymers; and
the second-type organic particles comprise one or more of a copolymer of an acrylic monomer unit and a styrene monomer unit, a copolymer of an acrylic acid monomer unit and the styrene monomer unit, a copolymer of the acrylic acid monomer unit, the acrylic monomer unit, and the styrene monomer unit, a copolymer of the styrene monomer unit and an unsaturated nitrile monomer unit, a copolymer of the styrene monomer unit, an alkylene monomer unit, and the unsaturated nitrile monomer unit, and modified compounds of the foregoing copolymers.

13 . The separator according to claim 9 , wherein the second-type organic particles comprise one or more of a butyl acrylate-styrene copolymer, a butyl methacrylate-isooctyl methacrylate copolymer, an isooctyl methacrylate-styrene copolymer, a methacrylate-methacrylic acid-styrene copolymer, a methyl acrylate-isooctyl methacrylate-styrene copolymer, a butyl acrylate-isooctyl acrylate-styrene copolymer, a butyl acrylate-isooctyl methacrylate-styrene copolymer, a butyl methacrylate-isooctyl methacrylate-styrene copolymer, a butyl methacrylate-isooctyl acrylate-styrene copolymer, a styrene-acrylonitrile copolymer, a styrene-butadiene-acrylonitrile copolymer, a methyl acrylate-styrene-acrylonitrile copolymer, an isooctyl methacrylate-styrene-acrylonitrile copolymer, a styrene-vinyl acetate copolymer, a styrene-vinyl acetate-pyrrolidone copolymer, and modified compounds of the foregoing copolymers.

14 . The separator according to claim 1 , wherein the thickness of the inorganic particle layer is ≥5 μm.

15 . The separator according to claim 1 , wherein a median volume-based particle size D v 50 of the inorganic particles is 0.5 μm-2.5 μm.

16 . The separator according to claim 1 , wherein the inorganic particles comprise one or more of boehmite (γ-AlOOH), aluminum oxide (Al 2 O 3 ), barium sulfate (BaSO 4 ), magnesium oxide (MgO), magnesium hydroxide (Mg(OH) 2 ), silicon dioxide (SiO 2 ), tin oxide (SnO 2 ), titanium oxide (TiO 2 ), calcium oxide (CaO), zinc oxide (ZnO), zirconium oxide (ZrO 2 ), yttrium oxide (Y 2 O 3 ), nickel oxide (NiO), cerium dioxide (CeO 2 ), zirconium titanate (SrTiO 3 ), barium titanate (BaTiO 3 ), and magnesium fluoride (MgF 2 ).

17 . The separator according to claim 1 , wherein the separator satisfies one or more of the following (1) to (5):
(1) an air permeability of the separator is 100 s/100 mL-300 s/100 mL; (2) a tensile strength in transverse direction (MD) of the separator is 1500 kgf/cm 2 -3000 kgf/cm 2 ; (3) a tensile strength in machine direction (TD) of the separator is 1000 kgf/cm 2 -2500 kgf/cm 2 ; (4) a transverse elongation at break of the separator is 50%-200%; and (5) a longitudinal elongation at break of the separator is 50%-200%.

18 . The separator according to claim 1 , wherein the inorganic particles and the organic particles form an uneven pore structure on the coating layer.

19 . The separator according to claim 1 , wherein: a distance between any two adjacent inorganic particles is recorded as L1, a distance between any one inorganic particle and any one organic particle that are adjacent is recorded as L2, and then L1<L2.

20 . A secondary battery, comprising a separator according to claim 1 .

Assignees

• Contemporary Amperex Technology Co Ltd

Inventors

• Lan Yuanyuan
• Yang Jianrui
• Hong Haiyi
• Cheng Cong
• Liu Na
• Jin Haizu

Classifications

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• 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

• H01M50/46

  Separators, membranes or diaphragms characterised by their combination with electrodes · CPC title

• H01M50/446 Primary

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

• H01M50/449 Primary

  having a layered structure · CPC title