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Diaphragm, preparing method of diaphragm and lithium ion battery

A diaphragm and substrate technology, applied in the field of diaphragm, can solve the problems of increasing the migration resistance of lithium ions in the electrolyte, reducing the high temperature resistance of the battery diaphragm, and poor adhesion of sheet-like flexible substrates, so as to improve the conductivity of lithium ions, Improved electrolyte resistance and perfect effect of heat-resistant layer

Active Publication Date: 2014-10-01
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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Examples

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preparation example Construction

[0021] The present invention also provides a method for preparing a diaphragm, the steps comprising:

[0022] S1. Prepare the polymer matrix containing the initiator and / or curing agent after mixing the polymer raw material with the initiator and / or curing agent. Wherein, the mixing of the polymer raw material and the initiator and / or curing agent is preferred in the present invention, and based on the quality of the polymer raw material, the content of the initiator and / or curing agent is 0.1-1wt%. The method for preparing the polymer base material containing the initiator and / or curing agent from the mixture of the polymer raw material and the initiator and / or curing agent is not limited in the present invention, such as biaxial stretching, etc., the preferred method of the present invention is by spinning Preparation of polymeric substrates containing initiators and / or curing agents.

[0023] S2, attaching the ceramic slurry to the surface of the polymer matrix, and post-c...

Embodiment 1

[0040] This example is used to illustrate the separator disclosed in the present invention and its preparation method.

[0041] 1. Preparation of polymer matrix

[0042] Polyethylene was mixed with 0.85wt% dicyandiamide, and a polymer matrix containing a curing agent was prepared by spinning. The thickness of the prepared polymer matrix was 35 μm, and the porosity was 50%.

[0043] 2. Preparation of slurry

[0044] Mix the epoxy resin E-51 of 1 weight part with the toluene of 39 weight parts evenly, then add 10 weight parts of Al 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.

[0045] 3. Preparation of slurry layer and curing

[0046] Immerse the polymer matrix obtained in step 1 into the ceramic slurry, take it out after 10 minutes, and att...

Embodiment 2

[0048] 1. Preparation of polymer matrix

[0049] Polypropylene was mixed with 0.73 wt % azobisisoheptanonitrile, and a polymer matrix containing a curing agent was prepared by spinning. The thickness of the prepared polymer matrix was 26 μm and the porosity was 71%.

[0050] 2. Preparation of slurry

[0051] Mix 1 part by weight of acrylate-terminated oligosiloxane TA10 with 42.5 parts by weight of benzene, and then add 8 parts by weight of ZnSO 4 , after fully stirring and mixing evenly, transfer to a ball mill for ball milling until ZnSO 4 The average particle size is 110nm, and the specific surface area is 23m 2 / g to obtain a ceramic slurry, and then heat the ceramic slurry to 110°C for later use.

[0052] 3. Preparation of slurry layer and curing

[0053] Immerse the polymer matrix obtained in step 1 into the ceramic slurry, take it out after 8 minutes, and attach 0.92 μm thick ceramic slurry to both sides of the polymer matrix, and then place it at 100 ° C for 20...

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Abstract

The invention provides a diaphragm, a preparing method of the diaphragm and a lithium ion battery comprising the diaphragm. The diaphragm comprises a polymer substrate and slurry layers positioned at the inside and on the surface of the substrate; each slurry layer comprises ceramic particles and curing resin; the curing resin is obtained through performing cross-linking and curing reaction on curing agents or initiating agents positioned inside the substrate and cross-linking resin positioned in the slurry layers; the high-temperature-resistant performance of the diaphragm is excellent; a heat-resistant layer cannot easily fall; and the winding, the preparation and the practical application are easier.

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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IPC IPC(8): H01M2/16H01M10/0525H01M50/403H01M50/411H01M50/414H01M50/434H01M50/451
CPCY02E60/122H01M10/0525H01M50/409Y02E60/10
Inventor 陈小芳苗伟峰
Owner BYD CO LTD
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