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Lithium ion battery composite membrane and preparation method thereof

A lithium-ion battery and composite diaphragm technology, which is applied in secondary batteries, battery pack components, circuits, etc., can solve the problems of complex process and difficult control of process conditions, and achieve simple process, excellent thermal stability, and improved thermal stability. sexual effect

Active Publication Date: 2016-09-21
东莞市魔方新能源科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Such as the Chinese patents whose publication numbers are CN102569701A and CN102610773A, the composite diaphragm is obtained by first coating the insulating layer of inorganic particles on the diaphragm and then coating the polymer coating; but the preparation process of the diaphragm requires multiple coatings, and the process is relatively Complex and difficult to control process conditions
In addition, there is also a method of mixing and coating inorganic particles and polymers, such as the Chinese patent with the publication number CN103441230B, but the preparation process requires pre-heating and swelling, so the process is also more complicated

Method used

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  • Lithium ion battery composite membrane and preparation method thereof
  • Lithium ion battery composite membrane and preparation method thereof
  • Lithium ion battery composite membrane and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] Preparation of positive electrode sheet:

[0032] Lithium cobaltate (positive electrode active material), conductive agent superconducting carbon (Super-P), and binder polyvinylidene fluoride (PVDF) were uniformly mixed at a mass ratio of 96:2.0:2.0 to make positive electrode slurry, and the slurry Coated on the aluminum foil of the current collector, and then dried at 110°C, then cold-pressed, slitting, trimmed, and tab-welded to make the positive electrode sheet of the lithium-ion battery.

[0033] Preparation of negative electrode sheet:

[0034] Graphite and conductive agent superconducting carbon (Super-P), thickener sodium carboxymethyl cellulose (CMC), and binder styrene-butadiene rubber (SBR) are made into negative electrode slurry at a mass ratio of 96:1.5:1.0:1.5 The slurry is coated on the copper foil of the current collector, and then dried at 85°C, then cold-pressed, stripped, trimmed, and tab-welded to make a lithium-ion battery negative electrode sheet. ...

Embodiment 2

[0042] Different from Example 1 is the preparation of composite diaphragm:

[0043] Preparation of composite diaphragm:

[0044] 1) Take a polyethylene microporous film with a thickness of 9 μm as the diaphragm substrate;

[0045] 2) Add polyoxyethylene and styrene-butadiene to deionized water, stir at 50°C for 2 hours, wherein the mass ratio of polyoxyethylene and styrene-butadiene is 92:8, and agglomerate into large particles Suspension dispersion; then add ZrO 2 The particles were stirred for 1h, and then added polyacrylate emulsion (the content of polyacrylate in the aqueous solution was 25wt%) and continued to stir for 1h, wherein, ZrO 2 The mass ratio to polyacrylate is 85:15, ZrO 2 The mass ratio to polyoxyethylene is 60:40 to obtain a mixed slurry of inorganic particles and binding polymer, and the solid content of the mixed slurry is 40wt%;

[0046] 3) Coating the mixed slurry obtained in step 2) on both sides of the diaphragm substrate by gravure coating, and dry...

Embodiment 3

[0049] Different from Example 1 is the preparation of composite diaphragm:

[0050] Preparation of composite diaphragm:

[0051] 1) Take a polyethylene microporous film with a thickness of 9 μm as the diaphragm substrate;

[0052] 2) Add polymethyl methacrylate and styrene-butadiene to deionized water, stir at 40°C for 2h, wherein the mass ratio of polymethyl methacrylate and styrene-butadiene is 94: 6. Agglomerate into a suspension dispersion of large particles; then add boehmite particles and stir for 1 hour, then add carboxymethyl cellulose sodium and continue stirring for 1 hour, wherein the mass ratio of boehmite to carboxymethyl cellulose sodium is 90:10, the mass ratio of boehmite and polymethyl methacrylate is 70:30, obtain the mixed slurry of inorganic particles and binding polymer, the solid content of this mixed slurry is 45wt%;

[0053] 3) Coating the mixed slurry obtained in step 2) on one side of the diaphragm substrate by screen printing, and drying to obtain ...

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Abstract

The invention belongs to the technical field of lithium ion batteries, and especially relates to a lithium ion battery composite membrane and a preparation method thereof. The composite membrane comprises a membrane substrate and a composite coating which is coated on at least one surface of the membrane substrate; the composite coating comprises an inorganic particle, a polymer and a binder; the polymer forms adhesive polymers through the binder; and the adhesive polymers are distributed in the inorganic particle and protrude out of the surface of the inorganic particle. Compared with the prior art, the inorganic particle in the composite coating has excellent heat stability, and suppresses heat shrinkage of a traditional membrane substrate under high temperature conditions, so that the heat stability of the membrane substrate can be greatly improved; and meanwhile, the protruded adhesive polymers in the composite coating can be bonded together with a pole piece in a lithium ion battery to suppress deformation of the battery, so as to guarantee the safety and smoothness of the battery. Furthermore, the preparation method of the lithium ion battery composite membrane provided by the invention is simple in process, easy in operation and the obtained membrane is high in consistency.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion batteries, and in particular relates to a lithium-ion battery composite diaphragm and a preparation method thereof. Background technique [0002] Lithium-ion batteries are widely used in consumer electronics products and products that need to provide power and energy storage due to their advantages such as large specific energy, high working voltage, long cycle life, and environmental friendliness. However, the safety of lithium-ion batteries has always been an important issue in the industry matter of great concern. Among them, the diaphragm used to isolate the positive and negative electrodes plays a vital role in the safety of lithium-ion batteries. At present, the commonly used separators in the industry are mainly polyolefin films such as polyethylene and polypropylene; however, the melting point of general polyolefin separators is ≤200°C. Once short-circuit heating occurs, the polyolefi...

Claims

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Application Information

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IPC IPC(8): H01M2/14H01M2/16H01M10/0525H01M50/403H01M50/443H01M50/446H01M50/491
CPCH01M10/0525H01M50/431H01M50/403H01M50/449H01M50/411Y02E60/10
Inventor 汪圣龙蒋中林
Owner 东莞市魔方新能源科技有限公司
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