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Polyalkylene microporous diaphragm for lithium ion battery and manufacturing method thereof

A lithium-ion battery, microporous technology, applied in battery pack components, chemical instruments and methods, circuits, etc., can solve the problems of easy stretching of batteries, low production performance and use performance, and unsafety, so as to prevent fire and explosion accidents, improved mechanical properties, and simple manufacturing process

Inactive Publication Date: 2009-12-02
许贵斌
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0016] At present, the closed cell temperature of single-layer microporous polypropylene membrane is 170°C or higher. The disadvantage of this temperature is that it is close to the melting point of lithium, which is obviously unsafe.
The closed cell temperature of the single-layer microporous polyethylene film is relatively low at 135°C, which is more suitable, but its membrane rupture temperature is also low, close to 145°C, that is, the temperature difference between the closed cell temperature and the membrane rupture temperature is only 10°C. ℃, that is, its heat resistance is poor, which is very unsafe. Moreover, the elastic recovery of the single-layer microporous polyethylene film is poor, which leads to easy stretching when it is loaded into the battery, so its production performance and use performance are not good. is very low, so thermoplastic resin single-layer microporous membranes need to be improved in terms of safety and reliability.

Method used

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  • Polyalkylene microporous diaphragm for lithium ion battery and manufacturing method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0054] In polypropylene (M w =4.8×10 5 , melt index is 2.1, melting point 170 ℃), add 30% ethylene-propylene copolymer for blending and granulation, and then add 25% weight unit ratio of this blend into one of the twin-screw extruders (Φ58mm, L / D=48, high shear form), and the liquid paraffin of 75% weight unit ratio is added to twin-screw extruder by side feeding, by making polypropylene blend in twin-screw extruder at 250 The liquid paraffin was melted and mixed under the conditions of ℃ and 200rpm to form a polypropylene blend solution, and the obtained solution was extruded from the two surface layers of the three-layer die through a metering pump, and the thickness of each layer was about 170 μm.

[0055] Simultaneously the high-density polyethylene (ρ=0.968g / cm 3 ,M w =3.5×10 5 ) into another twin-screw extruder (Φ58mm, L / D=48, high-shear form), and 75% liquid paraffin in the weight unit ratio is added to the twin-screw extruder by side feeding. In a screw extruder, ...

Embodiment 2

[0058] 25% by weight of polypropylene (M w =4.8×10 5, melt index is 2.1, fusing point 170 ℃) adds wherein a twin-screw extruder (Φ58mm, L / D=48, high-shear form), and the liquid paraffin of 75% weight unit ratio is added into by side feeding Twin-screw extruder, by melting polypropylene at 250°C and 200rpm in the twin-screw extruder and mixing liquid paraffin to form a polypropylene solution, the obtained solution is pumped from the two surface layers of the three-layer die through a metering pump Extrusion, the thickness of each layer is 170 μm.

[0059] At the same time in high-density polyethylene (ρ = 0.958g / cm 3 ,M w =6.8×10 5 ) into 35% ethylene-propylene copolymer for blending and granulation, and then 25% of this mixture by weight unit ratio is added into a twin-screw extruder (Φ58mm, L / D=48, high shear form), and 75 The liquid paraffin of % weight unit ratio is joined into twin-screw extruder by side feeding, by making polyethylene melt and mix liquid paraffin und...

Embodiment 3

[0062] 25% by weight of polypropylene (M w =4.8×10 5 , melt index is 2.1, fusing point 170 ℃) adds wherein a twin-screw extruder (Φ58mm, L / D=48, high-shear form), and the liquid paraffin of 75% weight unit ratio is added into by side feeding Twin-screw extruder, by melting polypropylene at 250°C and 200rpm in the twin-screw extruder and mixing liquid paraffin to form a polypropylene solution, the obtained solution is pumped from the two surface layers of the three-layer die through a metering pump Extrusion, the thickness of each layer is 170 μm.

[0063] At the same time in high-density polyethylene (ρ = 0.958g / cm 3 ,M w =6.8×10 5 ) into 30% ethylene-propylene copolymer for blending and granulation, and then 25% of this mixture by weight unit ratio is added to a twin-screw extruder (Φ58mm, L / D=48, high shear form), and 75 The liquid paraffin of % weight unit ratio is joined into twin-screw extruder by side feeding, by making polyethylene melt and mix liquid paraffin unde...

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Abstract

This invention discloses a micro-porous membrane of POLYALLYLALCOHOL / TiO2 for lithium-ion battery and its manufacturing method, which uses multilayer materials, formed by overlapping of a layer of polyethylene, PP and others, and improved heat-induced phase separation process to make the overall structure of polyolefin multilayer micro-porous membrane. In the neighboring layers of polyethylene and polypropylene, at least one layer contains a certain amount of ethylene-propylene copolymer to improve their compatibility. Its advantages are: 1) this structure realizes lower shutting hole and higher breaking film temperature without affecting other performance, to enhance the temperature and safety of the membrane. 2) The membrane is not easy to curl with high resistance and high mechanical strength to external injury, increasing the reliability of processing and use. 3) The simple manufacturing process can be realized only on the basis of the general heat-induced phase separation.

Description

technical field [0001] The patent of the present invention relates to the field of development and manufacture of lithium-ion batteries, in particular to a polyene microporous separator for lithium-ion batteries and a manufacturing method thereof. Background technique [0002] In 1991, SONY successfully launched the first commercial lithium-ion battery, which triggered the rapid development of a new generation of rechargeable batteries. Compared with nickel-cadmium batteries and nickel-metal hydride batteries, lithium-ion batteries have the advantages of high energy density, long life and high voltage. Lithium-ion batteries are currently widely used in automobiles, motorcycles, electric bicycles, especially portable electronic products, such as notebook computers, mobile phones, cameras, mp3, mp4 and other products. The composition of lithium-ion batteries includes: lithium cobalt oxide positive stage, carbon negative electrode, electrolyte and separator. Among them, the d...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M2/16B32B27/32C08J5/18H01M50/403H01M50/417H01M50/457H01M50/489H01M50/491
CPCY02E60/10
Inventor 许贵斌
Owner 许贵斌