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A method for irradiation modification of lithium-ion battery diaphragm

A lithium-ion battery, modified technology, applied in the direction of secondary batteries, battery components, circuits, etc., can solve the problem of lithium-ion battery cycle performance and charge-discharge efficiency reduction, porosity and air permeability decrease, easy to change the film, etc. problems, achieve high porosity and air permeability, reduce heat shrinkage, and increase liquid absorption

Active Publication Date: 2019-08-09
惠州华大辐照科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For example, Chinese patent document CN104882581A discloses a diaphragm, which is prepared by soaking the PE microporous membrane substrate in a vinyl siloxane solution system, and producing a grafting reaction after γ-ray irradiation. The prepared diaphragm has the characteristics of strong liquid absorption and liquid retention, low thermal shrinkage rate, and high safety. However, due to the strong penetrating ability of γ-rays and the diaphragm is soaked in the monomer solution, the monomer solution will block the polyolefin. The pores inside the film can easily change the pore structure of the film after grafting, resulting in a decrease in porosity and air permeability, and an increase in internal resistance, resulting in a decrease in the cycle performance and charge-discharge efficiency of lithium-ion batteries.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Embodiment 1, the method for irradiation modification lithium-ion battery diaphragm of the present invention

[0028] Embodiment 1 of the present invention The method for irradiating a modified lithium-ion battery separator comprises the following steps:

[0029] S1. Cut the polyolefin film into strips of 5 cm × 5 cm, ultrasonically wash with acetone for 20 minutes to remove surface-adsorbed impurities, and vacuum-dry at 50° C. for 12 hours to obtain a pretreated polyolefin film;

[0030] S2. Soak the pretreated polyolefin film in the step S1 in a nonionic polyacrylamide aqueous solution, fill the polyacrylamide aqueous solution with the pores of the microporous membrane, and then take it out to obtain the soaked polyolefin film. The final polyolefin film is washed with ethanol and dried with hot air to obtain a microporous film whose pores are filled and protected by polyacrylamide aqueous solution;

[0031] S3. Prepare the grafting solution, which is composed of solv...

Embodiment 2

[0034] Embodiment 2, the method for irradiation modification lithium-ion battery diaphragm of the present invention

[0035] Embodiment 2 of the present invention The method for irradiating a modified lithium-ion battery separator includes the following steps:

[0036] S1. Cut the polyolefin film into strips of 5 cm × 5 cm, ultrasonically wash with acetone for 15 minutes to remove surface-adsorbed impurities, and vacuum-dry at 50° C. for 10 hours to obtain a pretreated polyolefin film;

[0037]S2. Soak the pretreated polyolefin film in the step S1 in a nonionic polyacrylamide aqueous solution, fill the polyacrylamide aqueous solution with the pores of the microporous membrane, and then take it out to obtain the soaked polyolefin film. The final polyolefin film is washed with ethanol and dried with hot air to obtain a microporous film whose pores are filled and protected by polyacrylamide aqueous solution;

[0038] S3. Prepare grafting solution, which is composed of solvent, g...

Embodiment 3

[0041] Embodiment 3, the method for irradiation modification lithium-ion battery diaphragm of the present invention

[0042] Embodiment 3 of the present invention The method for irradiating a modified lithium-ion battery separator includes the following steps:

[0043] S1. Cut the polyolefin film into strips of 5 cm×5 cm, ultrasonically wash with acetone for 25 minutes to remove surface-adsorbed impurities, and vacuum-dry at 50° C. for 14 hours to obtain a pretreated polyolefin film;

[0044] S2. Soak the pretreated polyolefin film in the step S1 in a nonionic polyacrylamide aqueous solution, fill the polyacrylamide aqueous solution with the pores of the microporous membrane, and then take it out to obtain the soaked polyolefin film. The final polyolefin film is washed with ethanol and dried with hot air to obtain a microporous film whose pores are filled and protected by polyacrylamide aqueous solution;

[0045] S3. Prepare grafting solution, which is composed of solvent, gr...

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Abstract

The invention belongs to the technical field of lithium-ion batteries, and in particular relates to a method for modifying lithium-ion battery diaphragms by irradiation. The method for irradiating the modified lithium-ion battery separator includes the following steps: immersing the polyolefin film in a non-ionic polyacrylamide aqueous solution, filling the pores of the microporous membrane with the polyacrylamide aqueous solution, taking it out, cleaning with ethanol, Drying with hot air, dripping grafting solution on the surface of the membrane, irradiating grafting with ultraviolet light, extracting with distilled water for 6-10 hours after grafting, and drying with hot air to prepare a radiation-modified lithium-ion battery diaphragm. The lithium-ion battery separator prepared by the present invention not only increases the wettability of the electrolyte, but also can ensure that the microporous membrane has high porosity and transmittance, can meet the requirements of market development for the lithium-ion battery separator, and is suitable for popularization and application .

Description

technical field [0001] The invention belongs to the technical field of lithium-ion batteries, and in particular relates to a method for modifying lithium-ion battery diaphragms by irradiation. Background technique [0002] Lithium-ion batteries are widely used in portable electronic products such as notebook computers, mobile phones, and multimedia entertainment equipment due to their advantages such as small size, large capacity, convenient use, and reusability. As an important part of the battery, the diaphragm material isolates the positive and negative electrodes to prevent the short circuit of the battery, and at the same time allows the passage of conductive ions. It is called the "third pole" of the battery. Polyolefin film (PE film) is often used as a lithium-ion battery separator due to its good electrochemical and mechanical properties, but polyolefin is a non-polar material, and the electrolyte is usually based on dimethyl carbonate (DMC) and carbonic acid Polar ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M2/14H01M2/16H01M10/0525H01M50/403H01M50/417H01M50/491
CPCH01M10/0525H01M50/403H01M50/411Y02E60/10
Inventor 邹伟权万利秀辜英杰
Owner 惠州华大辐照科技有限公司