Diaphragm for lithium-ion battery and lithium-ion battery containing diaphragm

A lithium-ion battery and diaphragm technology, applied in secondary batteries, battery pack components, circuits, etc., can solve problems such as blockage of the separator, affecting battery performance, and plugging holes, and achieve the effect of solving deformation and improving battery performance

Pending Publication Date: 2019-07-12
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

Chinese patent CN101326658A is achieved by multiple coatings on the surface of the porous substrate to form a gradient change in the content ratio of the binder polymer / inorganic particles, but the multi-layer coating will seriously block the pores of the separator, which will affect the performance of the battery.
Chinese patent CN103441230A is achieved by mixing inorganic particles and bonding polymers, but it needs to be heated to pre-swell the polymers, and the swollen polymers will seriously block pores and affect battery performance.

Method used

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  • Diaphragm for lithium-ion battery and lithium-ion battery containing diaphragm
  • Diaphragm for lithium-ion battery and lithium-ion battery containing diaphragm
  • Diaphragm for lithium-ion battery and lithium-ion battery containing diaphragm

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Preparation of positive electrode sheet:

[0034] Lithium cobaltate, conductive carbon, and binder polyvinylidene fluoride were mixed uniformly in N-methylpyrrolidone (NMP) solvent at a mass ratio of 97:1.2:1.8 to make positive electrode slurry, which was then coated on aluminum foil and placed on After drying at 110°C, cold pressing, slitting, trimming, and tab welding are carried out to make positive plates.

[0035] Preparation of negative electrode sheet:

[0036] Mix graphite, conductive carbon, thickener sodium carboxymethyl cellulose, and binder styrene-butadiene rubber in deionized water at a mass ratio of 96:2.0:1.0:1.0 to make negative electrode slurry, and then coat it on copper foil After being dried at 85°C, cold pressing, slitting, trimming, and tab welding are carried out to make negative electrodes.

[0037] Preparation of diaphragm:

[0038] 1) Take a polypropylene microporous film with a thickness of 16 μm as the diaphragm body;

[0039] 2) Stir po...

Embodiment 2

[0043] The difference between this embodiment and Example 1 is the preparation of diaphragm:

[0044] 1) Take a polypropylene microporous film with a thickness of 16 μm as the diaphragm body;

[0045] 2) Stir polyvinylidene fluoride-hexafluoropropylene (with a particle size distribution range of 1.0-5.0 μm) and polyacrylonitrile (with a particle size distribution range of 0.1-0.4 μm) in a polyacrylic acid solution in deionized water, and polyvinylidene fluoride The weight ratio of vinyl fluoride-hexafluoropropylene: polyacrylonitrile: polyacrylic acid is 10:80:10, and the slurry prepared after stirring for 4 hours has a solid content of 20%, and then the prepared slurry is uniformly prepared by gravure coating The coating forms a functional coating on one side of the diaphragm body, and finally cuts it into pieces. Among them, the thickness of the functional coating is 4 μm, the forward projection area of ​​the functional coating accounts for 80% of the forward projection are...

Embodiment 3

[0048] The difference between this embodiment and Example 1 is the preparation of diaphragm:

[0049] 1) Take a polypropylene microporous film with a thickness of 16 μm as the diaphragm body;

[0050] 2) Stir polyacrylonitrile (particle size distribution range of 6.0-10.0 μm) and polyoxyethylene (particle size distribution range of 0.2-0.5 μm) in polyvinylidene fluoride solution in deionized water, polyacrylonitrile: poly The weight ratio of oxyethylene: polyvinylidene fluoride is 15:75:10, and the slurry prepared after stirring for 4 hours has a solid content of 20%, and then the prepared slurry is evenly coated on the diaphragm body by gravure coating A functional coating is formed on one side, and finally cut into pieces. Among them, the thickness of the functional coating is 8 μm, the forward projection area of ​​the functional coating accounts for 75% of the forward projection area of ​​the diaphragm body, and the area distribution ratio of the support area and the bondi...

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Abstract

The invention belongs to the technical field of lithium-ion batteries, and particularly relates to a diaphragm for a lithium-ion battery. The diaphragm comprises a diaphragm body, wherein at least onesurface of the diaphragm body is coated with a functional coating, the functional coating includes a first polymer, a second polymer and an adhesive, and the particle size distribution range value ofthe first polymer is greater than the particle size distribution range value of the second polymer. Compared with the prior art, the first polymer with a large particle size distribution range valueplays a supporting role, thereby being capable of forming a clearance between a pole plate and the diaphragm, providing an expansion space for the pole plate, and solving a deformation problem of thebattery; and the second polymer with a small particle size distribution range value plays a bonding role, thereby forming good contact with the pole plate after a hot processing process, thus forminga good interface between the diaphragm and the pole plate, and improving the battery performance. In addition, the invention further provides a lithium-ion battery containing the diaphragm for the lithium-ion battery.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a diaphragm for lithium ion batteries and a battery containing the diaphragm. Background technique [0002] As consumer electronics (mobile phones, tablets, notebooks, etc.) and new energy vehicles become more and more popular in people's lives, the demand for lithium-ion batteries is increasing, and the requirements for lithium-ion batteries are also increasing. [0003] The separator of the lithium-ion secondary battery is used as the isolation of the positive and negative electrodes, and is sandwiched between the positive and negative electrodes. The main function is to prevent the short circuit from direct contact between the positive and negative electrodes. At present, the separator is mainly composed of polyethylene, polypropylene and other polyolefin porous media. The polyolefin separator has a melting point below 200°C. , The separator is prone...

Claims

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Application Information

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IPC IPC(8): H01M2/16H01M10/0525H01M50/46
CPCH01M10/0525H01M50/461H01M50/411Y02E60/10
Inventor 汪圣龙曾黎蒋中林
Owner 东莞市魔方新能源科技有限公司
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