Diaphragm with reversible thermal shutdown performance, and preparation method and application thereof

A thermal shutdown and performance technology, applied in electrical components, electrochemical generators, circuits, etc., can solve the problems of few channels, unusable batteries, large lithium ion transmission impedance, etc., to improve safety performance and increase internal resistance , Extend the effect of application scenarios

Active Publication Date: 2020-09-11
JIANGSU ADVANCED MATERIAL TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] However, this kind of polymer microsphere layer usually has a certain thickness and is also closely packed together. The lithium ion path of the composite separator prepared in this way becomes longer and the channels become smaller, and the transmission impedance of lithium ions becomes larger.
Moreover, this kind of thermal shutdown effect is achieved by polymer microspheres melting to block ion channels, which is irreversible, and the battery cannot be used after thermal shutdown

Method used

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  • Diaphragm with reversible thermal shutdown performance, and preparation method and application thereof
  • Diaphragm with reversible thermal shutdown performance, and preparation method and application thereof
  • Diaphragm with reversible thermal shutdown performance, and preparation method and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0059] Example 1: Synthesis of polymer microspheres with core-shell structure

[0060] 600g of deionized water, 7.5g of sodium dodecylsulfonate, 7.5g of Tween 80, and 100g of cyclohexane were added to the high-pressure sealed reactor and replaced with nitrogen for 3 times. Then the temperature was raised to 70 ° C, and the stirring speed was 500 r min -1 ; Add 189g of 1,3-butadiene, 81g of styrene, 30g of ethylene glycol dimethacrylate monomers and 2.4g of ammonium persulfate as initiator to carry out polymerization reaction. After the reaction is kept for 6 hours, the temperature is lowered, the material is discharged, and spray-dried at a temperature not higher than 50° C. to obtain heat-responsive polymer microspheres whose outer shell is cross-linked styrene-butadiene rubber and whose core is cyclohexane.

[0061] The mass fraction of alkanes in the obtained polymer microspheres was 24.8%.

Embodiment 2-20

[0062] Example 2-20: Synthesis of polymer microspheres with core-shell structure

[0063] Example 2-20 Polymer microspheres with a core-shell structure were prepared in the same manner as in Example 1, except that the polymerized monomer and the inner core alkane were replaced, see Table 1.

[0064] Table 1 Different monomers and alkanes used to prepare polymer microspheres and the mass fraction of alkanes in the prepared polymer microspheres.

[0065]

Embodiment 21

[0066] Example 21: Preparation of Composite Diaphragm

[0067] Alumina powder (D50: 350nm), sodium polyacrylate aqueous solution (Lubrizol K702), acrylonitrile copolymer binder (Indile LA133) were added to the mixer according to the mass ratio of 97:0.7:6.3, and then Deionized water was added for slurry mixing and stirring, and the solid content was adjusted to 15% to obtain coating ceramic slurry.

[0068] The polymer microspheres in Example 1, sodium polyacrylate aqueous solution (Lubrizol K702), and styrene-butadiene rubber binder (Zion 451B) were added to the agitator according to the mass ratio of 90:0.5:9.5, and then Deionized water was added for slurry mixing and stirring, and the solid content was adjusted to 15% to obtain the coated polymer microsphere slurry.

[0069] The obtained coated ceramic slurry was coated on one side of the polyethylene base film by gravure coating, and the coating thickness was 3 μm. After the ceramic coating was dried, a ceramic PE separat...

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Abstract

The invention provides a diaphragm with reversible thermal shutdown performance, and a preparation method and application thereof. The diaphragm with reversible thermal shutdown performance includes:a base film; and a reversible thermal expansion polymer microsphere layer arranged on at least one surface of the base film. Different from irreversible thermal shutdown performance of existing polymer microspheres with high impedance, the thermal shutdown function of the lithium battery diaphragm is achieved through reversible thermal expansion polymer microspheres, the coating density is low, reversible thermal shutdown can be achieved at the low temperature (smaller than 130 DEG C), and the internal resistance of a battery is not obviously improved. Not only is the safety performance of thelithium battery improved, but also the application scene of the lithium battery is expanded.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion battery diaphragms, and in particular relates to a composite diaphragm with reversible thermal shutdown performance, and also relates to a preparation method and application of the composite diaphragm. Background technique [0002] Lithium-ion batteries have more and more applications in portable electronic products and electric vehicles because of their advantages over other types of batteries, such as specific capacity, self-discharge rate and cost performance. Among them, the diaphragm is one of the most critical components in the lithium battery structure. [0003] The main function of the diaphragm is to separate the positive and negative plates to prevent the short circuit in the battery, and at the same time allow lithium ions to pass through normally during normal charge and discharge to ensure the normal operation of the battery. The quality of its performance directly affects the sa...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/14H01M2/16H01M10/0525
CPCH01M10/0525Y02E60/10
Inventor 杨浩田王晓明刘勇标张磊包慧
Owner JIANGSU ADVANCED MATERIAL TECH CO LTD
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