Preparation method of power lithium battery diaphragm

A lithium battery separator and power technology, applied in the field of preparation of power lithium battery separator, can solve the problems of inability to meet the high-end field of lithium batteries, battery short circuit, complicated process, etc., and achieve high utilization rate of materials, easy operation and simple process. Effect

Inactive Publication Date: 2012-07-11
FOSHAN JINHUI HIGH TECH OPTOELECTRONICS MATERIAL
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  • Application Information

AI Technical Summary

Problems solved by technology

However, this three-layer separator still has great deficiencies in terms of tensile strength, puncture strength, and porosity, which lead to certain limitations in its use. Defects are easy to rupture and lead to short circuit of the battery. Therefore, to adapt to the development of lithium batteries in the high-end field, the battery separator must have good mechanical strength
In addition, due to the need for high-power charging and discharging, the power battery requires better air permeability and higher porosity.
However, due to the complex process, the current multi-layer separator has great deficiencies in porosity control, which cannot meet the needs of the high-end field of lithium batteries.

Method used

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  • Preparation method of power lithium battery diaphragm

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preparation example Construction

[0024] The preparation method of power lithium battery separator of the present invention, it comprises the following steps:

[0025] Dissolution: use polyolefin resin with high boiling point and small molecular weight compound as solvent, heat and stir to form a homogeneous solution;

[0026] Adding additives: adding additives to the uniformly mixed solution;

[0027] Extrusion and casting: use a twin-screw extruder to heat-extrude the solution through a die, and then cool it on a casting roll to form a gel sheet;

[0028] Stretch into film: After preheating the thick sheet, stretch it from both vertical and horizontal directions to form a film;

[0029] Shaping: After the stretched film is eluted with an extractant, the solvent is dried and heat-set to obtain a polyolefin resin microporous membrane, that is, a lithium battery separator.

Embodiment 1

[0032] Use ultra-high molecular weight polyethylene (UHMWPE, M w =5×10 6 , melting point 134°C) as polyethylene raw material, add 10 parts by weight of UHMWPE and 89.9 parts by weight of dibutyl phthalate into the mixing tank, heat, stir and mix evenly, then add 0.1 part of antioxidant and defoamer Add it to the twin-screw extruder through the precise metering system, melt and mix polyethylene at 220 ° C and 200 rpm in the twin-screw extruder to form a polyethylene solution, and the obtained solution is extruded from the die through a metering pump ;The film extruded through the die is rapidly cooled to room temperature to obtain a gel-like 800-2500um thick film. The film is then preheated at 120°C. After preheating, it is stretched along the vertical and horizontal directions. Stretching 10 times, the stretched film was washed with dichloromethane, dried and heat-set at 100°C to obtain a 16 μm polyethylene microporous separator.

Embodiment 2

[0034] Use ultra-high molecular weight polyethylene (UHMWPE, M w =3.4×10 6 , melting point 134°C) as polyethylene raw materials, add 20 parts by weight of UHMWPE and 79 parts by weight of decane into the mixing tank, heat and stir to mix evenly, then add 1 part of antioxidant and defoamer, through the precise metering system Add it to the twin-screw extruder, melt and mix polyethylene at 220°C and 200rpm in the twin-screw extruder to form a polyethylene solution, and the obtained solution is extruded from the die through a metering pump; through the die The extruded membrane is rapidly cooled to room temperature to produce a gel-like 800-2500um thick membrane. The membrane is then preheated at 120°C. After preheating, it is stretched 10 times along the vertical and horizontal directions. The stretched film was washed with hexane, dried and then heat-set at 110° C. to obtain a 16 μm polyethylene microporous separator.

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Abstract

The invention relates to the technical field of lithium batteries, in particular to a preparation method of a power lithium battery diaphragm. The preparation method comprises the following steps of dissolving, assistant adding, extruding, sheeting casting, diaphragm forming by drawing, shaping and the like, and a polyolefin resin microporous membrane, namely a lithium battery diaphragm, is formed finally. The diaphragm prepared by the method is 10-25 mu m thick, has a preferential porosity being 40-70%, and 105 DEG C heat shrinkage rate below 5%. The prepared diaphragm has the advantages of low closed-pore temperature, high fusing temperature, low heat shrinkage rate, good mechanical properties and has excellent safety performance when used as a power lithium battery diaphragm. In addition, the power lithium battery diaphragm is a polyolefin resin microporous sinlge-layer membrane which has good heat stability after being subjected to process steps such as drawing and shaping.

Description

technical field [0001] The invention relates to the technical field of lithium batteries, in particular to a method for preparing a power lithium battery diaphragm. Background technique [0002] New battery materials are key materials for developing energy technology and improving energy production and utilization efficiency. With the increasing demand for new battery materials in China's fast-growing economy, the Chinese government will continue to support the research and development of new battery materials in terms of policies and funds. develop. At the same time, the increasingly perfect production technology and price advantages will enhance the competitiveness of my country's new battery material manufacturers, and battery downstream products such as mobile phones, notebook computers, digital cameras, video cameras, automobiles and other products still maintain a high demand for new, high-efficiency, and environmentally friendly new battery materials. With strong dema...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/16B29C55/02H01M50/417H01M50/489H01M50/491
CPCY02E60/12B29K2023/00B29K2105/041B29C55/02H01M10/052H01M2/1653B29C55/005H01M2/16Y02E60/10H01M50/417H01M50/491H01M50/489
Inventor 张凯何永彬蔡朝辉吴耀根廖凯明
Owner FOSHAN JINHUI HIGH TECH OPTOELECTRONICS MATERIAL
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