Separator, having improved electrode adhesion and resistance property, for lithium secondary battery, and lithium secondary battery comprising same separator

A lithium secondary battery and separator technology, which is applied in the field of lithium secondary batteries, can solve the problems of different phase separation rates, increased process complexity, uneven pore structure and distribution of adhesive polymers, etc., to improve gas permeability , Improvement of output and life characteristics, effect of low interface resistance

Active Publication Date: 2020-08-21
LG ENERGY SOLUTION LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, when the two types of binder polymers are mixed, the process complexity increases and the phase separation rates of the two types of binder polymers are different, resulting in uneven pore structure and distribution of the binder polymers. , so that the desired adhesive polymer effect cannot be obtained

Method used

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  • Separator, having improved electrode adhesion and resistance property, for lithium secondary battery, and lithium secondary battery comprising same separator
  • Separator, having improved electrode adhesion and resistance property, for lithium secondary battery, and lithium secondary battery comprising same separator
  • Separator, having improved electrode adhesion and resistance property, for lithium secondary battery, and lithium secondary battery comprising same separator

Examples

Experimental program
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Embodiment 1

[0109] P(VDF-HFP-CTFE) terpolymer (Vinylidene fluoride-hexafluoropropylene-chlorotrifluoroethylene terpolymer, vinylidene fluoride-hexafluoropropylene-trifluoroethylene terpolymer) (weight average molecular weight: 500,000, containing 90 wt. % of repeating units derived from vinylidene fluoride, 5% by weight of repeating units derived from hexafluoropropylene and 5% by weight of repeating units derived from chlorotrifluoroethylene) were added to acetone and dissolved at 50°C for about 4 hours to prepare the binder polymer solution. 500nm Al as inorganic particles 2 o 3 The powder and 250 nm γ-AlOOH powder were mixed in a weight ratio of 9:1 and added to the binder polymer solution at a weight ratio of binder polymer:total inorganic particles=1:4. After adding cyanoethyl polyvinyl alcohol as a dispersant in an amount of 2% by weight of the total amount of inorganic particles, the inorganic particles were pulverized and dispersed for a total of 12 hours using a ball milling me...

Embodiment 2

[0111] A separator with a porous coating is produced by the same method as in Example 1, except that P(VDF-HFP-CTFE) terpolymer (Vinylidene fluoride-hexafluoropropylene-chlorotrifluoroethylene terpolymer, vinylidene fluoride-hexa Fluoropropylene-chlorotrifluoroethylene terpolymer) (weight average molecular weight: 500,000, containing 80% by weight of repeating units derived from vinylidene fluoride, 1% by weight of repeating units derived from hexafluoropropylene, and 19% by weight repeating units derived from chlorotrifluoroethylene).

Embodiment 3

[0113] A separator with a porous coating is produced by the same method as in Example 1, except that P(VDF-HFP-CTFE) terpolymer (Vinylidene fluoride-hexafluoropropylene-chlorotrifluoroethylene terpolymer, vinylidene fluoride-hexa Fluoropropylene-chlorotrifluoroethylene terpolymer) (weight average molecular weight: 500,000, containing 73% by weight of repeating units derived from vinylidene fluoride, 1% by weight of repeating units derived from hexafluoropropylene, and 26% by weight repeating units derived from chlorotrifluoroethylene).

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Abstract

The present invention relates to a separator for a lithium secondary battery and a lithium secondary battery comprising same. The separator for the lithium secondary battery comprises: a porous substrate; and a porous coating layer disposed on at least one surface of the porous substrate and comprising an inorganic particle and a binder polymer, wherein: the binder polymer is a terpolymer comprising a vinylidene fluoride (VDF) derived repeating unit, a hexafluoropropylene (HFP) derived repeating unit, and a chlorotrifluoroethylene (CTFE) derived repeating unit; the terpolymer comprises 65 to 90 wt% of the VDF derived repeating unit, 1 to 28 wt% of the HFP derived repeating unit, and 5 to 28 wt% of the CTFE derived repeating unit; and the separator for the lithium secondary battery has an electrode adhesion range of 30 gf / 25mm to 150 gf / 25mm and a heat shrinkage of 1 to 18% in the machine direction (MD) and 1 to 17% in the transverse direction (TD). The separator for the lithium secondary battery has uniform micropores formed on a surface thereof to increase an adhesive surface area to an electrode, thereby having an effect of improving the electrode adhesion.

Description

technical field [0001] The present disclosure relates to a separator for a lithium secondary battery having improved adhesion to electrodes and resistance characteristics and a lithium secondary battery including the same. [0002] This application claims the benefit of Korean Patent Application No. 10-2018-0116543 filed with the Korean Intellectual Property Office on September 28, 2018, the disclosure of which is hereby incorporated by reference in its entirety. Background technique [0003] Lithium secondary batteries are rechargeable energy storage devices with high energy density that reversibly convert chemical energy into electrical energy. Wide application in the device. Recently, applications to hybrid electric vehicles (HEV), plug-in electric vehicles (Plug-in EV), electric bicycles (e-bike) and energy storage systems (Energy storage system (ESS)) are rapidly expanding , in response to environmental concerns, high oil prices, energy efficiency and energy storage. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/16H01M10/052H01M50/443
CPCH01M10/052Y02E60/10H01M50/426H01M50/431H01M50/417H01M50/449H01M50/446H01M50/457H01M50/443H01M50/491H01M50/463H01M50/489H01M50/451H01M50/434
Inventor 郑邵美成东昱张大成
Owner LG ENERGY SOLUTION LTD
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