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Battery separator and preparation method thereof

A technology of battery separator and porous membrane, applied in the field of battery separator and its preparation, can solve the problems of accelerated battery thermal runaway, melt rupture, separator shrinkage, etc., and achieve the effect of improving thermal stability

Inactive Publication Date: 2015-06-24
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

As the matrix polymer of the diaphragm, polyolefin has the advantages of high strength, good acid and alkali resistance, and good solvent resistance, but the disadvantage is that the melting point is low (130 ° C ~ 160 ° C), and it is easy to shrink or melt at high temperatures.
When the thermal runaway of the battery occurs, the temperature reaches near the melting point of the polymer, the diaphragm shrinks and melts and ruptures, the positive and negative electrodes of the battery are short-circuited, and the thermal runaway of the battery is accelerated, which in turn leads to safety accidents such as battery fire and explosion.
[0004] The traditional method to improve the thermal safety of polyolefin separators is to scrape-coat ceramic nanoparticles (such as SiO2) on the surface of polyolefin separators. 2 Nano-powder) coating, and the introduction of coating will produce uneven lithium conduction current due to particle aggregation and "powder drop" phenomenon due to particle shedding

Method used

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  • Battery separator and preparation method thereof
  • Battery separator and preparation method thereof
  • Battery separator and preparation method thereof

Examples

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preparation example Construction

[0020] The preparation method of the battery separator provided in the embodiment of the present invention comprises the following steps:

[0021] S11, providing polyolefin porous membrane;

[0022] S12, attaching an oxidizing agent to the surface of the polyolefin porous membrane;

[0023] S13, providing a liquid phase medium having an organosiloxane compound, the organosiloxane compound includes a methacryloxy group and at least two alkoxy groups, the alkoxy group and the methacryloxy group are respectively Connecting with silicon atoms, heating the polyolefin porous membrane with oxidant adsorbed on the surface in the liquid medium, polymerizing the organosiloxane compound, and chemically grafting with the polyolefin porous membrane;

[0024] S14, providing an acidic environment or an alkaline environment, placing the grafted polyolefin porous membrane in an acidic environment or an alkaline environment, causing the siloxane groups to undergo condensation reactions to form...

Embodiment 1

[0072] Soak the Celgard-2300 diaphragm in the acetone solution of BPO (concentration: 2.5%, w / w) for 1 hour, take it out, dry it at room temperature, and put it into TEPM aqueous solution (concentration: 1%, v / v), Heated at 90°C for 2 hours, took it out, placed it in acetone for ultrasonic vibration to remove residual TEPM, and finally dried it in vacuum for 12 hours. The resulting membrane sample was labeled Celgard-PTEPM-2h.

Embodiment 2

[0074] It is basically the same as Example 1, except that it is heated at 90° C. for 4 hours, and the obtained membrane sample is marked as Celgard-PTEPM-4h.

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Abstract

The invention relates to a method for preparing a battery diaphragm, comprising the following steps: providing a polyolefin porous membrane; attaching an oxidizing agent to the surface of the polyolefin porous membrane; providing a liquid phase medium having an organosilicon compound, the organosilicon compound comprising A methacryloxy group and at least two alkoxy groups, the alkoxy group and the methacryloxy group are connected to silicon atoms respectively; heating in a medium to polymerize the organosiloxane compound, and graft it with the polyolefin porous membrane; provide an acidic environment or an alkaline environment, and place the grafted polyolefin porous membrane in an acidic environment or an alkaline environment, The siloxane group is condensed to form a cross-linked network structure, and the siloxane cross-linked network structure is grafted on the polyolefin porous membrane. The invention also relates to a battery separator.

Description

technical field [0001] The invention relates to a battery diaphragm and a preparation method thereof, in particular to a lithium ion battery diaphragm and a preparation method thereof. Background technique [0002] With the rapid development of lithium-ion batteries in new energy applications such as mobile phones, electric vehicles and energy storage systems, the safety of lithium-ion batteries is particularly important. Based on the analysis of the reasons for the safety of lithium-ion batteries, the safety of lithium-ion batteries can be improved from the following aspects: First, by optimizing the design and management of lithium-ion batteries, real-time monitoring and processing of the charging and discharging process of lithium-ion batteries , to ensure the safety of lithium-ion batteries, the second is to improve or develop new electrode materials to improve the intrinsic safety performance of the battery, and the third is to use a new type of safe electrolyte and dia...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M2/16H01M50/403H01M50/411H01M50/417H01M50/449H01M50/489
CPCH01M10/0525Y02E60/10H01M50/403H01M50/446H01M50/417H01M50/489H01M2220/20H01M2220/30
Inventor 赵鹏何向明杨聚平尚玉明王莉李建军高剑
Owner TSINGHUA UNIV
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