Three-layer membrane for lithium ion battery

A lithium-ion battery and separator technology, which is applied in battery pack parts, circuits, electrical components, etc., can solve the problems of high closed-cell temperature, the composite separator does not have high temperature resistance, and it is difficult to apply coatings, so as to ensure the protection and durability. Temperature performance and mechanical strength, guaranteed stability and tear strength, guaranteed peel strength and effect of stability

Inactive Publication Date: 2013-10-16
SHENZHEN ZHONGXING NEW MATERIAL TECH CO LTD
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  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The former has a high closed cell temperature, which poses a safety hazard, and the surface of the PP microporous membrane is not easy to coat with a coating, and the tear strength between the coating and the base film is low, and it is easy to fall off; Under high temperature, the thermal shrinkage is very large, there is almost no mechanical strength, and there are also potential safety hazards. The composite diaphragm of PE microporous membrane base membrane coated with ceramic coating does not have real high temperature resistance

Method used

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  • Three-layer membrane for lithium ion battery
  • Three-layer membrane for lithium ion battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] The structure of the three-layer separator used in the lithium ion battery in this example is as follows figure 1 As shown, it includes a polypropylene diaphragm layer 1, a ceramic coating 3, and a polyethylene diaphragm layer 2 sandwiched between the polypropylene diaphragm layer 1 and the ceramic coating 3. The specific preparation method includes hot-press laminating a polypropylene diaphragm with a thickness of 10 μm and a polyethylene diaphragm with a thickness of 10 μm, and then coating a ceramic coating with a thickness of 5 μm on the surface of the polyethylene diaphragm to form the composite diaphragm of the present application. And test the adhesion of the ceramic coating, the heat shrinkage rate of heating at 150°C for 1 hour, and the thermal shutdown temperature. The test results are shown in Table 1.

Embodiment 2

[0027] The structure of the three-layer separator for lithium-ion batteries in this example is the same as that of Example 1, except that the preparation method is changed. Specifically, a polypropylene / polyethylene composite base film with a thickness of 22 μm is prepared by a co-extrusion method. After the Celgard dry process is stretched into holes, a 5μm ceramic coating is applied to the polyethylene surface to make the composite diaphragm of this application, and the ceramic coating adhesion is tested, the heat shrinkage rate of heating at 150°C for 1 hour, and the heat Turn off the temperature. The test results are shown in Table 1.

[0028] Table 1 Performance test of composite diaphragm

[0029]

[0030] According to the test results in Table 1, it can be seen that compared with Comparative Example 1, the three-layer separator for lithium ion batteries of the present application overcomes the problem of low adhesion and easy shedding of the ceramic coating in the polypropy...

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PUM

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Abstract

The application discloses a three-layer membrane for a lithium ion battery. The membrane is composed of 3 composite layers, wherein a second composite layer is interlaid between a first composite layer and a third composite layer; the first composite layer comprises at least a heat-resistance layer with a porous structure; the second composite layer comprises at least a closed layer with a porous structure; the third composite layer comprises at least a ceramic layer with a porous structure. According to the membrane, the ceramic layer is in direct contact with the closed layer with a good surface coating property, thereby ensuring the peel strength and stability of the membrane. The heat-resistance layer can be used for guaranteeing the temperature resistance and mechanical strength of the membrane. Compared with a single-layer PP microporous membrane and a composite membrane with a ceramic coating, the three-layer membrane has the advantage that the high stability and the high tearing strength are guaranteed as the coating is unlikely to fall off. Compared with a single-layer PE microporous membrane and a composite membrane with a ceramic coating, the three-layer membrane has the advantage of better high temperature resistance.

Description

Technical field [0001] This application relates to the field of battery separators, in particular to a three-layer temperature-resistant composite separator for lithium-ion batteries. Background technique [0002] Polypropylene microporous film (PP film) and polyethylene microporous film (PE film) are two basic materials commonly used in battery separators. Most of the composite separators are based on PP microporous film or PE microporous film. Film composite. At present, the more common composite membranes include PP microporous membrane and ceramic coating on the PP microporous membrane; or PE microporous membrane and ceramic coating on the PE microporous membrane. Floor. The former has a high closed cell temperature, which poses a safety hazard, and the surface of the PP microporous film is not easy to be coated with a coating, and the tear strength between the coating and the base film is low and easy to fall off; the latter has poor temperature resistance, at 120℃ or high...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/18H01M50/451H01M50/457H01M50/489
CPCY02E60/12Y02E60/10
Inventor 曹志峰麻小挺
Owner SHENZHEN ZHONGXING NEW MATERIAL TECH CO LTD
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