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Method for improving thermal stability of lithium battery diaphragm

A lithium battery separator and thermal stability technology, applied in battery pack parts, circuits, electrical components, etc., can solve the problem that the heat resistance and porosity of the separator are difficult to balance, affect the infiltration of lithium ion conductive liquid, and affect the performance of lithium batteries, etc. problems, to achieve the effect of unaffected porosity, convenient operation and improved thermal stability

Inactive Publication Date: 2021-02-26
CHENDU NEW KELI CHEM SCI CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0009] At present, the widely used lithium battery polyolefin diaphragm has a very large safety hazard, and the technical method of coating the heat-resistant layer or flame-retardant layer in the prior art has a great impact on the porosity of the diaphragm, and will also affect the lithium ion. The conduction and infiltration of liquid affect the performance of lithium battery, and the lithium battery separator has the problem of difficult balance between heat resistance and porosity

Method used

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  • Method for improving thermal stability of lithium battery diaphragm

Examples

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Effect test

Embodiment 1

[0030](1) Preparation and modification of porous glass fiber: First, add alkali-free glass fiber to acetone to disperse evenly, then ultrasonically treat the surface at a frequency of 46kHz for 36min to clean the surface, separate the fiber by centrifugation, and then add a mixed solution of dilute hydrochloric acid and dilute sulfuric acid At 89°C, stir magnetically at a speed of 180r / min for 12.5h under heating in a water bath, centrifuge the fibers and wash them with deionized water to obtain porous glass fibers. Finally, slowly add hydrogen peroxide into the porous glass fiber dispersion to maintain the magnetic force Stir, heat up to 108°C, reflux for 5 hours, filter, and dry to obtain hydroxylated porous glass fibers; the average diameter of the alkali-free glass fibers is 3 μm; the concentration of the mixed solution of dilute hydrochloric acid and dilute sulfuric acid is 2.5mol / L; add hydrogen peroxide The amount is 18 times the mass of porous glass fiber;

[0031] (2)...

Embodiment 2

[0035] (1) Preparation and modification of porous glass fiber: First, add alkali-free glass fiber to acetone to disperse evenly, then ultrasonically treat the surface at a frequency of 42kHz for 38min to clean the surface, separate the fiber by centrifugation, and then add a mixed solution of dilute hydrochloric acid and dilute sulfuric acid In 88°C, stir magnetically at a speed of 150r / min for 13 hours under heating in a water bath, centrifuge the fibers and wash them with deionized water to obtain porous glass fibers. Finally, slowly add hydrogen peroxide into the porous glass fiber dispersion and keep magnetic stirring , heated to 106°C, refluxed for 5 hours, filtered, and dried to obtain hydroxylated porous glass fibers; the average diameter of the alkali-free glass fibers was 2 μm; the concentration of the mixed solution of dilute hydrochloric acid and dilute sulfuric acid was 1.5mol / L; the amount of hydrogen peroxide added 15 times the mass of porous glass fiber;

[0036...

Embodiment 3

[0040] (1) Preparation and modification of porous glass fiber: First, add alkali-free glass fiber to acetone to disperse evenly, then ultrasonically treat the surface at a frequency of 48kHz for 32min to clean the surface, separate the fiber by centrifugation, and then add a mixed solution of dilute hydrochloric acid and dilute sulfuric acid At 92°C, stir magnetically at a speed of 250r / min for 12 hours under heating in a water bath, centrifuge the fibers and wash them with deionized water to obtain porous glass fibers. Finally, slowly add hydrogen peroxide into the porous glass fiber dispersion and keep magnetic stirring , heated to 109°C, refluxed for 4 hours, filtered, and dried to obtain hydroxylated porous glass fibers; the average diameter of the alkali-free glass fibers was 4 μm; the concentration of the mixed solution of dilute hydrochloric acid and dilute sulfuric acid was 12.5mol / L; the amount of hydrogen peroxide added 25 times the mass of porous glass fiber;

[004...

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Abstract

The invention relates to the field of lithium battery diaphragms, and discloses a method for improving the thermal stability of a lithium battery diaphragm. The method specifically comprises the following steps of (1) adding alkali-free glass fibers into acetone for ultrasonic treatment, then adding into a mixed solution of diluted hydrochloric acid and dilute sulfuric acid for heating and stirring, separating and washing to obtain porous glass fibers, and then treating by utilizing hydrogen peroxide to obtain hydroxylated porous glass fibers, (2) mixing the hydroxylated porous glass fiber andparaffin, extruding by a screw, and repeatedly crushing and extruding the obtained rod-like mixed material to obtain paraffin / glass fiber composite powder, and (3) mixing the composite powder with polypropylene, carrying out melt electrospinning to obtain a modified polypropylene fiber membrane, and carrying out overlapping, melting and stretching to obtain the modified lithium battery diaphragmwith improved thermal stability. According to the method, the thermal stability of the diaphragm is remarkably improved, meanwhile, the porosity of the diaphragm is not affected, and the method is simple in process and convenient to operate and has an excellent application prospect.

Description

technical field [0001] The invention relates to the field of lithium battery separators, and discloses a method for improving the thermal stability of the lithium battery separators. Background technique [0002] Lithium batteries have many advantages such as large specific energy, long cycle life, and no environmental pollution. They are widely used in fields such as electric vehicles, hybrid vehicles, and energy storage batteries. Lithium batteries are mainly composed of four parts: positive and negative electrode materials, electrolyte, diaphragm and battery case. Among them, the separator, as one of the key components of the lithium battery, plays the role of preventing the short circuit of the positive and negative contacts and providing lithium ion transmission channels. The performance of the separator directly affects the electrochemical performance and safety performance of the lithium battery, so higher requirements are put forward for the performance of the separ...

Claims

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Application Information

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IPC IPC(8): H01M50/403H01M50/44H01M50/446
CPCY02E60/10
Inventor 陈庆廖健淞李钧司文彬
Owner CHENDU NEW KELI CHEM SCI CO LTD