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Residual oil rate control method, porous membrane, preparation method, and non-aqueous secondary battery

A control method and porous membrane technology, applied in secondary batteries, battery components, circuits, etc., can solve the problems of reducing battery electrical performance, high residual oil rate of diaphragm, increasing battery internal resistance, etc., and achieve the effect of optimizing performance

Inactive Publication Date: 2020-12-11
JIANGSU HORIZON NEW ENERGY TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In particular, the proportion of the number of blind holes in the separator directly affects the penetration performance of lithium ions in the battery. The larger the number of blind holes, the more invalid channels for ions, which increases the internal resistance of the battery and reduces the electrical performance of the battery; The main reason for blind holes in the diaphragm is that the residual oil rate in the diaphragm is too high, and the residual solvent in the diaphragm preparation process blocks the pores inside the diaphragm.

Method used

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  • Residual oil rate control method, porous membrane, preparation method, and non-aqueous secondary battery
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  • Residual oil rate control method, porous membrane, preparation method, and non-aqueous secondary battery

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Effect test

preparation example Construction

[0018] Further, see figure 2 The invention provides a method for preparing a polyolefin porous film, which includes: preparing a mixed solution, namely, mixing a solvent and a polyolefin composition; melting and kneading the mixed solution; extruding, cooling and solidifying to obtain a gel-like molded product; The gel-like molded product is stretched; the solvent is extracted by the method for controlling the residual oil rate as described above to obtain a polyolefin porous film with an ultra-low residual oil rate.

[0019] Optionally, the polyolefin composition includes high molecular polyethylene.

[0020] The specific preparation steps are as follows:

[0021] (1) The polyolefin composition and the solvent are mixed to form a mixed solution. Considering the consistency of the crystallinity of the separator, after mixing the polyolefin composition with a solvent (such as white oil), the content of the solvent is preferably 80-98% by mass. From the viewpoint of controll...

Embodiment 1

[0037] (1) Preparation of polyethylene solution

[0038] A polyethylene solution was prepared by mixing 15 parts by mass of high molecular weight polyethylene with a mass average molecular weight of 500,000 and 85 parts by mass of white oil.

[0039] (2) Preparation of gel-like sheet

[0040] The polyethylene solution was extruded from a die into a sheet at a temperature of 160° C., and then cast on a cooled metal roll to produce a gel-like sheet (also called a base tape).

[0041] (3) Stretching and heat setting

[0042] At a temperature of 100°C, the base tape was stretched in the length direction at a magnification of 5.5 times, then at a temperature of 115°C, the base tape was stretched in the width direction at a magnification of 14 times, and finally heat-treated at 134°C ( heat-fixed).

[0043] (4) Extraction and washing

[0044] The polyolefin porous membrane was continuously immersed in a chloroform bath divided into two tanks for 30 seconds, respectively, to extrac...

Embodiment 2

[0046] (1) Preparation of polyethylene solution

[0047] A polyethylene solution was prepared by mixing 10 parts by mass of high molecular weight polyethylene with a mass average molecular weight of 500,000 and 90 parts by mass of white oil.

[0048] (2) Preparation of gel-like sheet

[0049] The polyethylene solution was extruded from a die into a sheet at a temperature of 160° C., and then cast on a cooled metal roll to produce a gel-like sheet (also called a base tape).

[0050] (3) Stretching and heat setting

[0051] At a temperature of 100°C, the base tape was stretched in the length direction at a magnification of 5.5 times, then at a temperature of 115°C, the base tape was stretched in the width direction at a magnification of 14 times, and finally heat-treated at 134°C ( heat-fixed).

[0052] (4) Extraction and washing

[0053] The polyolefin porous membrane was continuously immersed in a tetrachloromethane bath divided into two tanks for 30 seconds, respectively,...

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Abstract

The invention belongs to the technical field of lithium battery diaphragms, and particularly relates to a residual oil rate control method, a porous membrane, a preparation method and a non-aqueous secondary battery. The residual oil rate control method comprises the following steps: dividing an extraction tank into a plurality of sections including an upstream tank and a downstream tank along themovement direction of an olefin microporous membrane; injecting a detergent into the downstream tank and causing the detergent to flow back to the upstream tank; and maintaining the detergent purityin the downstream tank to be higher than the detergent purity in the upstream tank. In the extraction process of the diaphragm, an oily solvent in the diaphragm can be effectively washed out, the residual oil rate of the diaphragm is controlled to be 0.1% or below, the wet diaphragm with the ultralow residual oil rate is manufactured, and the performance of the diaphragm is optimized.

Description

technical field [0001] The invention belongs to the technical field of lithium battery separators, and in particular relates to a residual oil rate control method, a porous membrane and a preparation method, and a non-aqueous secondary battery. Background technique [0002] With the development of the lithium battery industry, power batteries have become the direction of future development. As one of the four main materials of lithium batteries, the separator plays a very important role. Many characteristics of the separator have a very important impact on the battery. In particular, the proportion of the number of blind holes in the separator directly affects the passing performance of lithium ions in the battery. The greater the number of blind holes, the increase of ineffective channels of ions, which increases the internal resistance of the battery and reduces the electrical performance of the battery; The main reason for the occurrence of blind holes in the diaphragm is...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/14H01M2/16H01M2/18H01M10/0525
CPCH01M10/0525Y02E60/10
Inventor 王成豪李正林翁星星陈朝晖
Owner JIANGSU HORIZON NEW ENERGY TECH CO LTD