Composite diaphragm and preparation method thereof

A composite diaphragm and matrix film technology, which is applied in the field of lithium-ion batteries, can solve the problems of non-woven ceramic composite diaphragm without thermal shutdown performance, ceramic composite diaphragm powder falling off, polyolefin diaphragm with poor high temperature thermal stability, etc., and achieve excellent adhesion performance , low cost, and no pollution to the environment

Active Publication Date: 2018-05-15
SHANGHAI ENERGY NEW MATERIALS TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a composite diaphragm and its preparation method, which is used to solve the problem of poor high temperature thermal stability of polyolefin diaphragms in the prior art, and non-woven ceramic composite diaphragms without thermal shutdown. Performance and the problem of "powder dropping" of ceramic composite diaphragm

Method used

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  • Composite diaphragm and preparation method thereof

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preparation example Construction

[0029] Please refer to the attached figure 1 , the invention provides a kind of preparation method of composite membrane, described preparation method comprises the following steps at least:

[0030] Step S1 is firstly performed, providing a base film, and placing the base film in a magnetron sputtering chamber.

[0031] As an example, the base film is wound on a winder in the magnetron sputtering chamber, and the speed of the winder is set at 10-25 m / min. By installing a winding machine in the magnetron sputtering chamber and winding the base film on the winding machine, the continuous production of the magnetron sputtering composite diaphragm can be realized. This production method has low requirements on equipment, Low cost and no pollution to the environment.

[0032] As an example, the base film is a high-temperature-resistant non-woven diaphragm, which can mainly be polyethylene terephthalate, polyimide, polyarylsulfone, polyacrylonitrile, polyamide or polyetheretherke...

Embodiment 1

[0052] A method for preparing a composite diaphragm with thermal shutdown and high thermal stability of the present invention, the preparation steps include:

[0053] 1) Wind the high-temperature-resistant polyethylene terephthalate non-woven fabric film on the winding machine in the sputtering chamber, and set the speed of the winding machine to 15m / min;

[0054] 2) Using polyethylene as the first target material, magnetron sputtering a low melting point polymer coating on both sides of the base film, the sputtering conditions are: power 150W, vacuum degree 0.005Pa, reaction temperature 30°C.

[0055] 3) with high purity Al 2 o 3 As the second target material, a ceramic coating is formed by sputtering on the surface of the low-melting point polymer coating. The sputtering conditions are: power 100W, vacuum degree 0.008Pa, and reaction temperature 20°C.

[0056] The obtained composite separator has an electrolyte retention rate of 368%, a closed cell temperature of 135°C, a ...

Embodiment 2

[0058] A method for preparing a composite diaphragm with thermal shutdown and high thermal stability of the present invention, the preparation steps include:

[0059] 1) Wind the high-temperature-resistant polyimide non-woven fabric film on the winding machine in the sputtering chamber, and set the speed of the winding machine to

[0060] 23m / min;

[0061] 2) Using polycaprolactone as the first target material, magnetron sputtering a low melting point polymer coating on both sides of the base film, the sputtering conditions are: power 115W, vacuum degree 0.008Pa, reaction temperature 40°C;

[0062] 3) with high purity TiO 2 As the second target material, a ceramic coating is formed by sputtering on the surface of the low-melting point polymer coating. The sputtering conditions are: power 90W, vacuum degree 0.01Pa, and reaction temperature 22°C.

[0063] The obtained composite separator has an electrolyte retention rate of 388%, a closed cell temperature of 80°C, a membrane r...

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Abstract

The invention provides a preparation method of a composite diaphragm, at least comprising: first, providing basic film, and placing the basic film in a magneto sputtering cavity; second, using a low-melting-point polymer as a first target material to form a low-melting-point polymer coating on each side of the basic film by surface sputtering; third, using ceramic material as a second target material to form a ceramic coating on each polymer coating by surface sputtering. The composite diaphragm is 19-40 mu m in thickness, has porosity of 40-70%, average pore size of 0.1-0.5 mu m, pore closingtemperature of 80-160 DEG C and film breaking temperature of 250-450 DEG C. The preparation method has low equipment requirement and low cost and is applicable to large-scale industrial production. The composite diaphragm prepared herein has excellent resistance to high temperature, thermal shutdown performance, electrolyte wettability and mechanical properties. In addition, the ceramic coatingsin the diaphragm are well adhesive to a base material, and no picking occurs.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, in particular to a composite diaphragm with thermal shutdown and high thermal stability and a preparation method thereof. Background technique [0002] A lithium-ion battery consists of a positive electrode, a negative electrode, an electrolyte, and a separator. The diaphragm material mainly plays the role of isolating the positive and negative electrodes to prevent internal short circuit in the lithium-ion battery, and at the same time retains a large amount of electrolyte to ensure the smooth conduction of lithium ions in the diaphragm. The existing commercial polyolefin porous separator has thermal shutdown performance, but its thermal stability is insufficient at high temperatures, which can easily cause a large area of ​​short circuit in the battery, cause thermal runaway of the battery, and cause safety hazards such as battery explosion and spontaneous combustion. Therefore, in order t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/14H01M2/16H01M10/0525H01M50/403H01M50/414H01M50/434H01M50/44H01M50/451H01M50/457
CPCH01M10/0525H01M50/403H01M50/431H01M50/411H01M50/449Y02E60/10
Inventor 程跃彭锟
Owner SHANGHAI ENERGY NEW MATERIALS TECH CO LTD
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