Preparation method of battery diaphragm and battery membrane

A battery diaphragm and base film technology, which is applied in the direction of secondary batteries, battery pack components, circuits, etc., can solve the problem of unsatisfactory battery performance, increased tortuosity of the pore diameter of the composite diaphragm, and inconsistent porosity of the two-layer coating and other problems, to achieve the effect of ensuring heat resistance, good liquid absorption rate, and good liquid retention rate

Inactive Publication Date: 2016-03-30
SHENZHEN ZHONGXING NEW MATERIAL TECH CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The disadvantage of this patented technology is that the three-layer separator is generally thicker, the thickness is usually above 16 μm, and the melting point of the PP layer is 165°C, the heat resistance is limited, and the battery safety performance is not enough.
For example, in the patent application CN103733380A, it is mentioned that inorganic particles are used to coat porous substrates to form a composite diaphragm; however, the bonding performance between this type of composite diaphragm and the positive and negative electrodes of the battery is poor, and the battery performance cannot reach the desired effect.
In the patent application CN102569701, it is mentioned that two coating methods are used on the diaphragm material, the ceramic particles are coated for the first time, and the polymer is coated for the second time, and the polymer plays a bonding role; however, the disadvantage of this method is that the two The cost of coating is high, and the porosity of the two coatings is inconsistent, which increases the tortuosity of the pore diameter of the composite separator and affects the performance of the battery

Method used

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  • Preparation method of battery diaphragm and battery membrane
  • Preparation method of battery diaphragm and battery membrane
  • Preparation method of battery diaphragm and battery membrane

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] The battery separator in this example is figure 1 As shown, it includes a base film 1 and a coating 2 coated on the surface of the base film. The coating 2 contains organic particles 3 and irregular inorganic particles 4 . In this example, a 12 μm polypropylene microporous membrane is used as the base membrane, the inorganic particles are alumina particles with a D50 of 700 nm, the organic particles are copolymer particles of vinylidene fluoride and hexafluoropropylene with a particle size of 200 nm, and deionized water is used as the solvent. and N-methylpyrrolidone, the water-soluble dispersant adopts sulfonate, and the wetting agent adopts ethanol.

[0033] The preparation method of the battery separator of this example is as follows:

[0034] Weigh 25.2g inorganic particles, 10.8g organic particles, 0.72g water-soluble dispersant, 3.5g wetting agent, 1.2g viscosity modifier, 88.1g deionized water, 1.5g organic solvent, and put all the materials into the mixer , 20...

Embodiment 2

[0045] The battery diaphragm of this example is the same as that of Example 1, except that the inorganic particles use boehmite particles with a D50 of 710nm, and the organic particles use copolymer particles of acrylonitrile and methyl methacrylate with a particle size of 500nm, replacing the inorganic particles of Example 1. The amount of particles and organic particles, inorganic particles and organic particles is the same as in Example 1, the preparation method is the same as in Example 1, and the remaining components and amounts of the slurry are the same as in Example 1. A battery separator was prepared by the same method as in Example 1.

[0046] Similarly, the same test method was used to test the battery separator of this example, and the test results are shown in Table 1.

Embodiment 3

[0048] The battery diaphragm of this example is the same as that of Example 1, except that the inorganic particles use alumina particles with a D50 of 750nm, and the organic particles use polymethyl methacrylate particles with a particle size of 300nm, replacing the inorganic particles and organic particles of Example 1. The amount of particles and organic particles is the same as in Example 1, the preparation method is the same as in Example 1, and the remaining components and amounts of the slurry are the same as in Example 1. A battery separator was prepared by the same method as in Example 1.

[0049] Similarly, the same test method was used to test the battery separator of this example, and the test results are shown in Table 1.

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Abstract

The application discloses a preparation method of battery membrane and a battery membrane. The preparation method of the invention comprises: evenly dispersing irregularly shaped inorganic particles with D50 of 0.4-2.0 mum and organic particles with particle diameters less than 1 mum in solvent, preparing into slurry, coating the slurry on base membrane, drying, removing the solvent, and obtaining the battery membrane; the solvent comprises deionized water and organic solvent; the volume ratio of the deionized water to the organic solvent is 50-100:1. The preparation method of the application is simple, convenient and easy in operation; the heat resistance of the battery membrane is ensured and the cohesiveness of the battery membrane and the cathode and anode sheets is improved by using inorganic particles and organic particles of different sizes and shapes in the slurry, simultaneously using the deionized water and the organic solvent and using complementation of the two kinds of particles; the liquid absorptivity and liquid retention rate of the battery membrane are improved by mixed use of the two kinds of solvents; the circulation of the battery is improved, and the foundation for preparing high safety performance lithium ion battery is established.

Description

technical field [0001] The present application relates to the field of battery diaphragms, in particular to a method for preparing a battery diaphragm and the prepared battery diaphragm. Background technique [0002] A lithium battery consists of a positive electrode, a negative electrode, a separator, and an electrolyte. As one of the four major materials of lithium batteries, the diaphragm is an important component in lithium batteries, although it does not participate in the electrochemical reactions in the battery. As the diaphragm of lithium-ion batteries, the diaphragm represented by polyolefin microporous membrane plays the role of isolating positive / negative electrodes and providing ion conduction channels in lithium-ion batteries, and its performance has great influence on the safety and electrical properties of lithium-ion batteries. have important influences. In addition, key properties such as battery capacity, cycle performance, and charge-discharge current de...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/14H01M2/16H01M10/0525H01M50/403H01M50/446H01M50/489
CPCH01M10/0525H01M50/446H01M50/403H01M50/411H01M50/449Y02E60/10
Inventor 张辉曹志锋瞿威
Owner SHENZHEN ZHONGXING NEW MATERIAL TECH CO LTD
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