A diaphragm, its preparation method and a lithium-ion battery

A separator and polymer technology, used in secondary batteries, battery pack components, circuits, etc., can solve the problem of increasing the migration resistance of lithium ions in the electrolyte, reducing the high temperature resistance of battery separators, and the adhesion of sheet-like flexible substrates. It can improve the lithium ion conductivity, improve the electrolyte resistance, and improve the heat resistance layer.

Active Publication Date: 2017-02-08
BYD CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the coating prepared by the above method has poor adhesion to the sheet-shaped flexible substrate. The ceramic layer and the substrate only rely on the adhesive in the ceramic layer to bond, and the bonding strength is weak. And during the charging and discharging process of the battery, the coating particles are more likely to fall off, thereby reducing the high temperature resistance of the battery separator produced according to the above method, and the falling ceramic particles will also cause uneven performance of the separator and affect the consistency of battery performance. ; It will also increase the migration resistance of lithium ions in the electrolyte, which is not conducive to fast charging and fast discharging; it may also migrate to the surface of the positive and negative electrodes, affecting the insertion and extraction of lithium ions; it may even cause pinholes in the diaphragm, causing a short circuit between the positive and negative electrodes of the battery etc., seriously affect battery performance and affect its practical application

Method used

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  • A diaphragm, its preparation method and a lithium-ion battery
  • A diaphragm, its preparation method and a lithium-ion battery

Examples

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preparation example Construction

[0030] The present invention also provides a method for preparing a diaphragm, the steps comprising:

[0031] S1. The polymer matrix containing the self-initiating UV-curable cross-linking resin is prepared by mixing the polymer raw material with the self-initiating UV-curable cross-linking resin. Wherein, the mixing of the polymer raw material and the self-initiating UV-curable cross-linking resin is not limited in the present invention. Preferably, based on the quality of the polymer raw material, the content of the self-initiating UV-curable cross-linking resin is 1-5wt %. The method for preparing a polymer matrix containing a self-initiating UV-curable cross-linking resin from a mixture of a polymer raw material and a self-initiating UV-curable cross-linking resin, such as biaxial stretching, is preferred in the present invention, by A polymer matrix containing a self-initiating UV-curable cross-linked resin was prepared by spinning.

[0032] S2. After the ceramic slurry...

Embodiment 1

[0049] This example is used to illustrate the separator disclosed in the present invention and its preparation method.

[0050] 1. Preparation of polymer matrix

[0051] Polyethylene is mixed with 1wt% unsaturated polyester amide urea (urea 0.04mol%), and a polymer matrix containing self-initiating UV-curable crosslinking resin is prepared by spinning, and the thickness of the prepared polymer matrix is ​​35 μm , Porosity 50%.

[0052] 2. Preparation of slurry

[0053] The unsaturated polyester amide urea (urea 0.04mol%) of 1 weight part is mixed with the toluene of 39 weight parts, then adds the Al of 10 weight parts wherein 2 o 3 , after fully stirring and mixing evenly, transfer to a ball mill for ball milling until Al 2 o 3 The average particle size is 200nm, and the specific surface area is 10m 2 / g to obtain a ceramic slurry, and then heat the ceramic slurry to 80°C for subsequent use.

[0054] 3. Preparation of slurry layer and curing

[0055] Immerse the polyme...

Embodiment 2

[0057] 1. Preparation of polymer matrix

[0058] Polyethylene was mixed with 4.5wt% vinyl acrylate, and a polymer matrix containing a self-initiating UV-curable crosslinking resin was prepared by spinning. The thickness of the prepared polymer matrix was 35 μm, and the porosity was 63%.

[0059] 2. Preparation of slurry

[0060] The vinyl acrylate of 1 weight part and the carbon tetrachloride of 41 weight parts are mixed uniformly, then add the MgO of 10 weight parts wherein, after fully stirring and mixing, transfer to ball mill and carry out ball milling, to MgO average particle size 60nm, ratio Surface area is 43m 2 / g to obtain ceramic slurry, and then heat the ceramic slurry to 70°C for later use.

[0061] 3. Preparation of slurry layer and curing

[0062] Immerse the polymer matrix obtained in step 1 in the ceramic slurry, take it out after 10 minutes, attach 0.8 μm thick ceramic slurry to both sides of the polymer matrix, and then place it under a 100W high-pressure ...

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Abstract

The invention provides a diaphragm, a preparation method thereof and a lithium ion battery containing the diaphragm. The diaphragm includes a polymer matrix and a slurry layer located inside and on the surface of the matrix; the polymer matrix contains a polymer substrate and a cured resin, and the slurry layer contains ceramic particles and a cured resin; the cured resin passes through the polymer The base material and the paste layer can be obtained by self-initiating UV-curable cross-linking resin cross-linking and curing. The prepared separator has excellent high-temperature resistance, the heat-resistant layer is not easy to fall off, and is easier to wind, prepare and apply.

Description

technical field [0001] The invention relates to a separator, its preparation method and a lithium ion battery. Background technique [0002] The separator of lithium-ion secondary batteries is usually a thin porous insulating material, which has high ion permeability, good mechanical strength, and long-term stability to various chemicals and chemical solvents. Therefore, the non-conductivity of the separator is used to separate the positive and negative electrodes of the battery to prevent the two electrodes from contacting and short circuit; at the same time, relying on the microporous structure of the separator itself, lithium ions can easily pass through and maintain good ionic conductivity between the positive and negative electrodes. . When an abnormally large current is generated inside the battery due to an external short circuit or wrong connection, when the internal temperature of the battery rises to a certain level, the diaphragm will be thermally melted and the ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M2/16H01M10/0525H01M50/403H01M50/417H01M50/42H01M50/423H01M50/434H01M50/451H01M50/457H01M50/491
CPCH01M10/0525H01M50/403H01M50/446H01M50/451H01M50/491H01M50/42H01M50/423H01M50/417H01M50/434H01M50/457Y02E60/10
Inventor 陈小芳苗伟峰
Owner BYD CO LTD
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