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Diaphragm, preparation method thereof, and lithium ion battery using diaphragm

A diaphragm and heat-sensitive technology, which is applied in the direction of separator/film/diaphragm/spacer components, secondary batteries, battery pack components, etc. Damaged and other problems, to improve thermal stability, prevent thermal runaway, and improve safety

Active Publication Date: 2019-01-04
CONTEMPORARY AMPEREX TECH CO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the disadvantages of this method are: when thermal runaway occurs, the temperature rises quickly, and the polymer has no time to respond to melting. As the overcharge continues, the structure of the positive electrode is continuously destroyed, lithium is gradually deposited on the surface of the negative electrode, and the thermal stability of the positive and negative electrodes When the temperature of the battery reaches the melting temperature of the polymer, the positive and negative electrodes have reacted violently with the electrolyte and a large amount of heat is generated. In the case of a large area of ​​closed cells, the battery has already experienced thermal runaway

Method used

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  • Diaphragm, preparation method thereof, and lithium ion battery using diaphragm
  • Diaphragm, preparation method thereof, and lithium ion battery using diaphragm
  • Diaphragm, preparation method thereof, and lithium ion battery using diaphragm

Examples

Experimental program
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Effect test

Embodiment 1

[0043] Preparation of heat-expandable microspheres

[0044] 1) Preparation of aqueous phase dispersion: add 10 parts of dispersant (wherein sodium chloride accounts for 30wt.%, magnesium chloride accounts for 45wt.%, sodium hydroxide accounts for 25wt.%) into 300 parts of deionized water, after stirring at room temperature for 30min , add 1 part of sodium lauryl sulfate solution (2% by weight) and mix uniformly to obtain an aqueous phase dispersion;

[0045] 2) Preparation of oil phase dispersion: 100 parts of polymerizable monomer (wherein acrylonitrile accounts for 20wt.%, methyl methacrylate accounts for 30wt.%, vinylidene chloride accounts for 50wt.%) and 20 parts of blowing agent 3- Methyl heptane, 1 part of initiator azobisisobutyronitrile, and 0.5 part of crosslinking agent ethylene glycol diformic acid acrylate are mixed uniformly to obtain an oil phase dispersion;

[0046] 3) Homogenization: After mixing the above-mentioned aqueous phase dispersion liquid and oil pha...

Embodiment 2

[0049] The preparation method of Example 2 is basically the same as that of Example 1, except that 2,4-dimethylhexane with a boiling point of 109° C. is used as a foaming agent to prepare thermally expandable microspheres.

Embodiment 3

[0051] The preparation method of Example 3 is basically the same as that of Example 1, except that heptane with a boiling point of 98° C. is used as a foaming agent to prepare thermally expandable microspheres.

[0052] It can be understood that, although this description takes Examples 1 to 3 as examples to illustrate the preparation of thermally expandable microspheres, those skilled in the art can adjust the types and contents of related substances as required, for example:

[0053] In the preparation method of the diaphragm, in parts by weight, the polymerizable monomer is 100 parts; the crosslinking agent is 0.05-10 parts; the initiator is 0.1-10 parts; the foaming agent is 10-100 parts; the dispersant is 0.1-20 parts; 100-2000 parts of deionized water.

[0054] In the preparation method of the diaphragm, the dispersant is selected from Ca, Mg, Na, Zn metal salts, oxides or hydroxides, methyl cellulose, hydroxypropyl methyl cellulose, carboxymethyl cellulose, silicon diox...

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Abstract

A diaphragm is disclosed, which comprises a porous diaphragm substrate and a heat-sensitive coating coated on at least one surface of the diaphragm substrate, wherein the heat-sensitive coating comprises 10 to 90 wt.% of thermal expansion microspheres and 3 to 15 wt.% of an adhesive, and the thermal expansion microsphere comprises a blowing agent and a thermoplastic polymer shell encapsulating theblowing agent. Compared with the prior art, the diaphragm of the present invention can prevent the occurrence of thermal runaway of the battery and remarkably improve the safety of the lithium ion battery by coating the heat-sensitive coating containing thermal expansion microspheres on the surface of the diaphragm. In addition, the invention also discloses a preparation method of the diaphragm and a lithium ion battery using the diaphragm.

Description

technical field [0001] The invention belongs to the field of batteries, and more specifically, the invention relates to a diaphragm, a preparation method thereof and a lithium ion battery using the diaphragm. Background technique [0002] Lithium-ion batteries are the key core components of new energy vehicles. With the rapid development of the power vehicle industry, the market demand for power batteries with high power output and fast charging and discharging is more urgent. At the same time, the safety performance of lithium-ion batteries is also raised. higher requirements. [0003] In recent years, due to the frequent occurrence of power battery safety accidents, the safety performance of lithium-ion batteries has attracted people's attention. The safety problem of lithium-ion batteries is essentially related to thermal runaway, that is, when the internal temperature of lithium-ion batteries is high (>120°C) due to various reasons during use, side reactions inside t...

Claims

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Application Information

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IPC IPC(8): H01M2/14H01M2/16H01M10/0525H01M50/403H01M50/414H01M50/449
CPCH01M10/0525H01M50/403H01M50/409Y02E60/10
Inventor 陈小波陈世龙
Owner CONTEMPORARY AMPEREX TECH CO
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