Lithium-ion battery separator, method for preparing same, and lithium-ion battery

Patent metadata

Field	Value
Publication number	US-2019237732-A1
Application number	US-201716319911-A
Country	US
Kind code	A1
Filing date	Aug 14, 2017
Priority date	Aug 29, 2016
Publication date	Aug 1, 2019
Grant date	—

Abstract

The disclosure relates to the field of lithium-ion batteries, and discloses a lithium-ion battery separator, a method for preparing same, and a lithium-ion battery. The lithium-ion battery separator includes: a porous basement membrane, and a heat-resistant layer covering at least one side surface of the porous basement membrane, where the heat-resistant layer contains a high-temperature-resistant polymer and inorganic nanometer particles; and the heat-resistant layer has a fiber-network shaped structure.

First claim

1 . A lithium-ion battery separator, comprising:
a porous basement membrane, and a heat-resistant layer covering at least one side surface of the porous basement membrane, wherein the heat-resistant layer contains a high-temperature-resistant polymer and inorganic nanometer particles, and the heat-resistant layer has a fiber-network shaped structure.

2 . The lithium-ion battery separator according to claim 1 , wherein a weight ratio of the high-temperature-resistant polymer to the inorganic nanometer material is 100:(3 to 50); or a weight ratio of the high-temperature-resistant polymer to the inorganic nanometer material is 100:(5 to 18).

3 . The lithium-ion battery separator according to claim 1 , wherein the heat-resistant layer is formed by a high-temperature-resistant polymer and an inorganic nanometer material, and the average diameter of a fiber in the heat-resistant layer is 100 nm to 2000 nm.

4 . The lithium-ion battery separator according to claim 1 , wherein the porosity of the heat-resistant layer is above 80%, and the single-sided surface density of the heat-resistant layer is 0.2 g/m2 to 15 g/m2.

5 . The lithium-ion battery separator according to claim 1 , wherein the heat-resistant layer is formed through electrostatic spinning by using a spinning solution containing a high-temperature-resistant polymer and inorganic nanometer particles.

6 . The lithium-ion battery separator according to claim 1 , wherein the melting point of the high-temperature-resistant polymer is not lower than 180° C., or the melting point of the high-temperature-resistant polymer is 200° C. to 600° C.

7 . The lithium-ion battery separator according to claim 1 , wherein the high-temperature-resistant polymer is at least one of polyetherimide, polyimide, polyetheretherketone, polyether sulfone, polyamide-imide, polyamide acid, and polyvinylpyrrolidone; or the high-temperature-resistant polymer is at least one of polyetherimide and polyetherether ketone.

8 . The lithium-ion battery separator according to claim 1 , wherein the average particle size of the inorganic nanometer particle is 50 nm to 3 μm; and the inorganic nanometer particle is at least one of Al2O3, SiO2, BaSO4, TiO2, CuO, MgO, LiAlO2, ZrO2, CNT, BN, SiC, Si3N4, WC, BC, AlN, Fe2O3, BaTiO3, MoS2, α-V2O5, PbTiO3, TiB2, CaSiO3, molecular sieve, clay, and kaolin.

9 . The lithium-ion battery separator according to claim 1 , wherein the porous basement membrane is a polymer membrane, and the polymer membrane is a polyolefin membrane; or the porous basement membrane is a ceramic membrane, and the ceramic membrane comprises a polymer membrane and a ceramic layer that is located on at least one side surface of the polymer membrane; the heat-resistant layer is located on a surface on a side of the ceramic membrane on which a ceramic layer is formed.

10 . The lithium-ion battery separator according to claim 1 , wherein the lithium-ion battery separator further comprises a bonding layer, the bonding layer is formed on an outermost side of at least one side surface of the lithium-ion battery separator, the bonding layer contains an acrylate crosslinked polymer and a styrene-acrylate crosslinked copolymer, or the bonding layer contains an acrylate crosslinked polymer and a vinylidene fluoride-hexafluoropropylene copolymer, or the bonding layer contains an acrylate crosslinked polymer, a styrene-acrylate crosslinked copolymer and a vinylidene fluoride-hexafluoropropylene copolymer; and the porosity of the bonding layer is 40% to 65%.

11 . The lithium-ion battery separator according to claim 10 , wherein the glass transition temperature of the acrylate crosslinked polymer is −20° C. to 60° C., the glass transition temperature of the styrene-acrylate crosslinked copolymer is −30° C. to 50° C., and the glass transition temperature of the vinylidene fluoride-hexafluoropropylene copolymer is −65° C. to −40° C.

12 . The lithium-ion battery separator according to claim 11 , wherein
the bonding layer contains the acrylate crosslinked polymer and the styrene-acrylate crosslinked copolymer and does not contain the vinylidene fluoride-hexafluoropropylene copolymer, and a weight ratio of the acrylate crosslinked polymer to the styrene-acrylate crosslinked copolymer is (1:0.05) to (1:2); or the bonding layer contains the acrylate crosslinked polymer and the vinylidene fluoride-hexafluoropropylene copolymer and does not contain the styrene-acrylate crosslinked copolymer, and a weight ratio of the acrylate crosslinked polymer to the vinylidene fluoride-hexafluoropropylene copolymer is (1:0.3) to (1:25); or the bonding layer contains the acrylate crosslinked polymer, the styrene-acrylate crosslinked copolymer, and the vinylidene fluoride-hexafluoropropylene copolymer, and a weight ratio of the acrylate crosslinked polymer to the styrene-acrylate crosslinked copolymer to the vinylidene fluoride-hexafluoropropylene copolymer is 1:(0.01 to 2):(0.3 to 5).

13 . The lithium-ion battery separator according to claim 12 , wherein
the acrylate crosslinked polymer is a mixture of a first acrylate crosslinked polymer and a second acrylate crosslinked polymer, or the acrylate crosslinked polymer is a mixture of a first acrylate crosslinked polymer and a third acrylate crosslinked polymer, or the acrylate crosslinked polymer is a mixture of a first acrylate crosslinked polymer, a second acrylate crosslinked polymer and a third acrylate crosslinked polymer, or the acrylate crosslinked polymer is the second acrylate crosslinked polymer, or the acrylate crosslinked polymer is the third acrylate crosslinked polymer, wherein the first acrylate crosslinked polymer contains a polymethyl methacrylate chain segment of 70 to 80 wt %, a polyethylene acrylate chain segment of 2 to 10 wt %, a polybutyl acrylate chain segment of 10 to 20 wt %, and a polyacrylic acid chain segment of 2 to 10 wt %, the second acrylate crosslinked polymer contains a polymethyl methacrylate chain segment of 30 to 40 wt %, a polyethylene acrylate chain segment of 2 to 10 wt %, a polybutyl acrylate chain segment of 50 to 60 wt %, and a polyacrylic acid chain segment of 2 to 10 wt %, and the third acrylate crosslinked polymer contains a polymethyl methacrylate chain segment of 50 to 80 wt %, a polyethylene acrylate chain segment of 2 to 10 wt %, a polybutyl acrylate chain segment of 15 to 40 wt %, and a polyacrylic acid chain segment of 2 to 10 wt %; the glass transition temperature of the first acrylate crosslinked polymer is 50° C. to 60° C., the glass transition temperature of the second acrylate crosslinked polymer is −20° C. to −5° C., and the glass transition temperature of the third acrylate crosslinked polymer is 30° C. to 50° C.; the styrene-acrylate crosslinked copolymer contains a polyphenyl ethylene chain segment of 40 to 50 wt %, a polymethyl methacrylate chain segment of 5 to 15 wt %, a polyethylene acrylate chain segment of 2 to 10 wt %, a polybutyl acrylate chain segment of 30 to 40 wt %, and a polyacrylic acid chain segment of 2 to 10 wt %; and the glass transition temperature of the styrene-acrylate crosslinked copolymer is 15° C. to 30° C.; and the vinylidene fluoride-hexafluoropropylene copolymer contains a polyvinylidene fluoride chain segment of 80 to 98 wt % and a polyhexafluoropropylene chain segment of 2 to 20 wt %; and the glass transition temperature of the vinylidene fluoride-hexafluoropropylene copolymer is −60° C. to −40° C.

14 . The lithium-ion battery separator according to claim 12 , wherein the bonding layer contains a first acrylate crosslinked polymer, a second acrylate crosslinked polymer, and the styrene-acrylate crosslinked copol

Assignees

• Byd Co Ltd

Inventors

• Hu Jialing
• Liu Ronghua
• Shan Jun
• He Long

Classifications

• H01M50/457

  comprising three or more layers · CPC title

• H01M50/451

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

• H01M50/417

  Polyolefins · CPC title

• H01M50/491

  Porosity · 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