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Lithium ion battery diaphragm, preparation method thereof, and lithium ion battery

A technology for lithium-ion batteries and diaphragms, applied in secondary batteries, battery pack components, circuits, etc., can solve the problems of reducing the electrochemical performance of batteries, reducing the porosity of diaphragms, and shedding of coating layers, so as to improve electrochemical stability The effect of window, high discharge capacity retention rate, and excellent electrolyte absorption rate

Inactive Publication Date: 2019-06-07
CHANGCHUN INST OF APPLIED CHEMISTRY - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the coating of inorganic particles has a significant effect on improving the wettability of the electrolyte, the coating layer and the support film need to be connected by an adhesive, and the thermal stability temperature of the adhesive also has a great influence on the thermal stability of the coating. After the binder softens, it loses its cohesive force, and the long-term charge-discharge cycle process will easily cause the coating layer to fall off
The exfoliation can easily block the nanochannels of the porous support membrane, reduce the porosity of the separator, and then reduce the electrochemical performance of the battery
At the same time, the coating of inorganic particles on the polyolefin porous membrane leads to a significant increase in the thickness of the separator, resulting in an increase in battery resistance and increased heat generation. At the same time, the increase in the thickness of the separator is not conducive to the miniaturization of the battery.

Method used

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

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preparation example Construction

[0053] The present invention also provides a kind of preparation method of above-mentioned lithium-ion battery diaphragm, comprises the following steps:

[0054] A) performing plasma treatment on the porous polyolefin-based membrane to obtain a pretreated porous polyolefin-based membrane;

[0055] B) first immersing the pretreated porous polyolefin base film in a phenolic solution, then adding silicate substances and aldehyde substances, and reacting to obtain a lithium-ion battery diaphragm.

[0056] In an embodiment of the present invention, the source of the porous polyolefin-based membrane is the same as above, and will not be repeated here.

[0057] In an embodiment of the present invention, before performing the plasma treatment on the porous polyolefin-based membrane, it also includes cleaning and drying the porous polyolefin-based membrane. In some embodiments, the cleaning agent includes acetone or absolute ethanol. The present invention has no special limitation on...

Embodiment 1

[0078] The porous polyolefin base film is a porous polyethylene film, which is prepared from polyethylene through a wet double-drawing process. The thickness of the porous polyethylene film is 25 μm, the porosity is 66%, the electrolyte absorption rate is 183%, and the ion conductivity is 0.206mS·cm -1 .

[0079] The porous polyethylene film is cleaned in acetone, then dried, the dried porous polyethylene film is placed in a plasma cleaning machine, and plasma treatment is performed for 10 minutes to obtain a pretreated porous polyethylene film;

[0080] Add 3-aminophenol into the solvent to prepare a phenolic solution. The solvent includes absolute ethanol with a volume ratio of 80:1:200, ammonia water and water with a mass concentration of 25 wt%.

[0081] Immerse the pretreated porous polyolefin base film in the phenolic solution for 10 minutes, then add tetraethyl orthosilicate and formaldehyde, the molar ratio of 3-aminophenol, tetraethyl orthosilicate and formaldehyde ...

Embodiment 2

[0089] The porous polyolefin base film is a porous polyethylene film, which is prepared from polyethylene through a wet double-drawing process. The thickness of the porous polyethylene film is 25 μm, the porosity is 66%, the electrolyte absorption rate is 183%, and the ion conductivity is 0.206mS·cm -1 .

[0090] The porous polyethylene film is cleaned in acetone, then dried, the dried porous polyethylene film is placed in a plasma cleaning machine, and plasma treatment is performed for 10 minutes to obtain a pretreated porous polyethylene film;

[0091] Add 3-aminophenol into the solvent to prepare a phenolic solution. The solvent includes absolute ethanol with a volume ratio of 60:1:220, ammonia water and water with a mass concentration of 25 wt%.

[0092] Immerse the pretreated porous polyolefin base film in the phenol solution for 10 minutes, then add tetraethyl orthosilicate and formaldehyde, the molar ratio of 3-aminophenol, tetraethyl orthosilicate and formaldehyde is...

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Abstract

The invention provides a lithium ion battery diaphragm, a preparation method thereof,k and a lithium ion battery. The lithium ion battery diaphragm comprises a porous polyolefin base membrane; a composite coating layer which wraps the surface of the porous polyolefin base membrane, wherein the compound coating layer comprises phenolic resin and silicon dioxide. According to the lithium ion batterydiaphragm provided by the invention, the phenolic resin and the silicon dioxide in the compound coating layer have a synergistic effect, so that the obtained lithium ion battery diaphragm has relatively good affinity with an electrolyte, and therefore, the lithium ion battery diaphragm has relatively good electrolyte absorptivity and relatively good electrolyte wettability. The lithium ion battery diaphragm disclosed by the invention is prepared into the lithium ion battery, so the lithium ion battery diaphragm and the electrolyte have relatively good compatibility, and the discharge capacityretention rate and coulombic efficiency of the obtained lithium ion battery are relatively high. In addition, the electrochemical stability window of the diaphragm is improved through the compound coating layer, and the diaphragm is hopeful to be applied to the field of high-voltage lithium batteries.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a lithium ion battery diaphragm, a preparation method thereof and a lithium ion battery. Background technique [0002] Lithium-ion batteries are composed of positive electrode materials, negative electrode materials, separators and electrolytes. Among them, the separator isolates the positive and negative electrodes, which can prevent the internal short circuit caused by the direct contact of the positive and negative electrodes, and provide a channel for lithium ion transport. The performance of the separator determines the interface structure and internal resistance of the battery, which directly affects the battery capacity, cycle and safety performance. A separator with excellent performance plays an important role in improving the overall performance of the battery. The general lithium-ion battery separator is made of polypropylene or polyethylene by dry sing...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/16H01M2/14H01M10/0525
CPCY02E60/10
Inventor 谷倩倩孙昭艳宋敬川
Owner CHANGCHUN INST OF APPLIED CHEMISTRY - CHINESE ACAD OF SCI
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