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Composite diaphragm, preparation method thereof and lithium ion battery

A technology of composite separator and fiber membrane, which is applied in the direction of secondary batteries, battery components, circuits, etc., can solve the problem of insufficient adhesion between coated spun fibers and positive and negative electrodes, poor high temperature resistance of battery separators, and impact on battery life. Service life and other issues to achieve the effect of improving shuttleability, good electric cycle performance and safety performance, good service life and stability

Pending Publication Date: 2020-11-06
ZHUHAI COSMX BATTERY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, although the fiber membrane has better compatibility with the polyolefin microporous base membrane than the ceramic coating, when it is prepared into a battery, the adhesion between the fiber membrane and the positive and negative electrodes is poor. It is easy to fall off during the process, which affects battery life
Coating fibers with a core-shell structure on one or both sides of the substrate can solve the problems of poor high temperature resistance of the battery separator and easy short circuit or even combustion explosion under high temperature conditions. The adhesion of the separator is insufficient, and the battery prepared by using the separator is easy to peel off during use, which affects the service life of the battery

Method used

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  • Composite diaphragm, preparation method thereof and lithium ion battery
  • Composite diaphragm, preparation method thereof and lithium ion battery
  • Composite diaphragm, preparation method thereof and lithium ion battery

Examples

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Embodiment 1

[0048] Embodiment 1 proposes a kind of composite diaphragm, and described composite diaphragm comprises a layer thickness about 7 μm, mechanical strength is about 1259kgf / cm 2 , a polyolefin porous base film with an air permeability value of about 152s / 100cc, one outer surface of the polyolefin porous base film is coated with an aramid fiber membrane with a thickness of about 2μm, and the air permeability value of the polyolefin porous base film increases by 10s / 100cc, On the surface of the aramid fiber membrane and the other outer surface of the polyolefin porous base membrane, an organic adhesive film is discontinuously distributed in sheets, and the coverage rate of the organic adhesive film on the surface of the aramid fiber membrane per square centimeter is about 37%.

[0049] The preparation method of the composite diaphragm of embodiment 1 comprises the steps:

[0050] (1) Firstly, 5 kg of dimethylacetamide solvent was mixed with 10 kg of aramid 1313 slurry and ultrason...

Embodiment 2

[0055] Embodiment 2 proposes a kind of composite membrane, and described composite membrane comprises a layer thickness about 7 μm, mechanical strength about 1259kgf / cm 2 , a polyolefin porous base film with an air permeability value of about 152s / 100cc, one outer surface of the polyolefin porous base film is coated with a fiber membrane with a thickness of about 2μm, and the air permeability value of the separator and fiber membrane at this time is measured to be 166s / 100cc. On the surface of the fiber membrane and the other outer surface of the polyolefin porous base membrane, an organic bonding film is discontinuously distributed in sheets, and the coverage of the organic bonding film on the surface of the fiber membrane per square centimeter is about 32%, and the organic bonding film per square centimeter The coverage of the bonding film on the surface of the polyolefin porous base film is about 32%.

[0056] The preparation method of the composite membrane of embodiment...

Embodiment 3

[0061] Embodiment 3 proposes a kind of composite membrane, and described composite membrane comprises a layer thickness about 7 μ m, mechanical strength is about 1259kgf / cm 2 , a polyolefin porous base membrane with an air permeability of about 152s / 100cc, one outer surface of the polyolefin porous base membrane is coated with a fiber membrane with a thickness of about 2 μm, and the surface of the fiber membrane and the other outer surface of the polyolefin porous base membrane The organic bonding film is distributed in a discontinuous sheet on the surface, and the coverage rate of the organic bonding film on the surface of the fiber membrane per square centimeter is about 32%, and the coverage rate of the organic bonding film on the surface of the polyolefin porous base film is about 32% per square centimeter. was 32%.

[0062] The preparation method of the composite membrane of embodiment 3 comprises the steps:

[0063] (1) First, 9.2 kg of deionized water and 0.8 kg of ara...

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Abstract

The invention relates to a composite diaphragm, a preparation method thereof and a lithium ion battery. The composite diaphragm is of a multi-layer structure, wherein the inner layer of the compositediaphragm is provided with more than one polyolefin porous base membrane, and the outermost layer of the composite diaphragm is an organic adhesive membrane; the composite diaphragm further comprisesat least one layer of fibrous membrane, and the fibrous membrane is arranged between the polyolefin porous base membrane and the organic adhesive membrane; wherein the coverage rate of each square centimeter of the organic adhesive membrane on the inner layer membrane structure adjacent to the organic adhesive membrane is 10%-50%. The composite diaphragm provided by the invention can ensure that the diaphragm has high mechanical strength and low air permeability, and provides a path for rapid transmission of lithium ions. Meanwhile, due to the arrangement of the organic adhesive membrane, thecohesiveness between the diaphragm and the positive and negative pole plates is also improved.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a composite diaphragm, a preparation method thereof and a lithium ion battery. Background technique [0002] Due to its high energy density, long cycle life, no memory effect, and environmental protection, lithium-ion batteries have strong competitiveness in the field of secondary batteries, and are widely used in the fields of mobile phones, notebook computers and other electronic products. Applications in fields such as automobiles and large energy storage equipment are also gradually increasing. Lithium-ion battery separator, as an important component, has a great influence on the electrical performance and safety performance of lithium-ion batteries. [0003] Therefore, in order to improve the electrical performance and safety performance of lithium-ion batteries, researchers have begun to study a variety of functional composite separators. For exa...

Claims

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Application Information

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IPC IPC(8): H01M2/16H01M2/14H01M10/0525
CPCH01M10/0525Y02E60/10
Inventor 贺飞李素丽徐延铭李俊义
Owner ZHUHAI COSMX BATTERY CO LTD