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Process for preparing high-performance lithium battery diaphragm by utilizing polyethylene grafted copolymer

A technology of polyethylene grafting and lithium battery separator, which is applied in lithium batteries, battery pack parts, non-aqueous electrolyte batteries, etc., can solve the problems of poor electrolyte affinity, short circuit, acupuncture, etc. Safety performance, the effect of eliminating internal stress

Active Publication Date: 2021-03-30
JIESHOU CITY TIANHONG PACKAGING MATERIAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, polyolefin separator materials are widely used in lithium batteries, mainly including polyethylene separators and polypropylene separators, but polyethylene separators and polypropylene separators have poor affinity for electrolytes, resulting in short circuits, overcharging, and acupuncture. And other issues

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] (1) Add 20g allyloxytrimethylsilane and 0.1g azobisisobutyronitrile to 500mL N,N-dimethylformamide, heat to 45°C and stir for 15min to obtain reactant I; Add 80g of linear low-density polyethylene to the mixture, heat to 70°C and stir for 15 minutes to obtain reactant II; then add reactant I dropwise to reactant II, maintain the temperature at 90°C during the dropping process, and keep the temperature for 8 hours after the addition is completed. After the reaction is finished, cool, filter, wash with water, and dry to obtain a polyethylene graft copolymer. In the post-treatment process, allyloxytrimethylsilane was removed by filtration, and the product was detected by infrared. It was found that the unsaturated double bond disappeared, and the infrared characteristic peak of siloxyl group appeared, indicating that allyloxytrimethylsilane was grafted to on polyethylene.

[0026] (2) After mixing 1000 g of polyethylene graft copolymer and 15 g of nano-sodium sulfate, put...

Embodiment 2

[0030] The steps of preparing the membrane in Example 2 are the same as in Example 1, except that the amount of nano-sodium sulfate is adjusted.

[0031] (1) Add 20g allyloxytrimethylsilane and 0.1g azobisisobutyronitrile to 500mL N,N-dimethylformamide, heat to 45°C and stir for 15min to obtain reactant I; Add 80g of linear low-density polyethylene to the mixture, heat to 70°C and stir for 15 minutes to obtain reactant II; then add reactant I dropwise to reactant II, maintain the temperature at 90°C during the dropping process, and keep the temperature for 8 hours after the addition is completed. After the reaction is finished, cool, filter, wash with water, and dry to obtain a polyethylene graft copolymer.

[0032] (2) After mixing 1000 g of polyethylene graft copolymer and 10 g of nano-sodium sulfate, put it into a twin-screw extruder, melt and extrude it at 190° C., cool and form it, and obtain a substrate.

[0033] (3) Biaxially stretch the substrate after preheating. The...

Embodiment 3

[0036] The steps of preparing the membrane in Example 3 are the same as those in Example 1, except that the amount of allyloxytrimethylsilane is adjusted.

[0037] (1) Add 25g allyloxytrimethylsilane and 0.1g azobisisobutyronitrile to 500mL N,N-dimethylformamide, heat to 45°C and stir for 15min to obtain reactant I; add 500mL xylene Add 80g of linear low-density polyethylene to the mixture, heat to 70°C and stir for 15 minutes to obtain reactant II; then add reactant I dropwise to reactant II, maintain the temperature at 90°C during the dropping process, and keep the temperature for 8 hours after the addition is completed. After the reaction is finished, cool, filter, wash with water, and dry to obtain a polyethylene graft copolymer.

[0038] (2) After mixing 1000 g of polyethylene graft copolymer and 15 g of nano-sodium sulfate, put it into a twin-screw extruder, melt and extrude it at 190° C., cool and shape it to obtain a substrate.

[0039] (3) Biaxially stretch the subst...

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PUM

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Abstract

The invention discloses a process for preparing a high-performance lithium battery diaphragm by utilizing a polyethylene graft copolymer, and relates to the technical field of lithium battery diaphragms. According to the present invention, allyloxytrisilane is used for graft modification of linear low-density polyethylene, siloxane groups are introduced into the molecular structure of polyethylene, and the novel polyethylene graft copolymer is processed into the diaphragm, so that the affinity of the polyethylene diaphragm to an electrolyte is improved, and the safety performance of the lithium battery is improved; and meanwhile, the mechanical property of the prepared diaphragm is ensured to adapt to machine winding during lithium battery assembly and the normal operation of the lithium battery.

Description

Technical field: [0001] The invention relates to the technical field of lithium battery diaphragms, in particular to a process for preparing high-performance lithium battery diaphragms by using polyethylene graft copolymers. Background technique: [0002] In the structure of lithium batteries, the separator is one of the key inner components. The performance of the separator determines the interface structure and internal resistance of the battery, which directly affects the capacity, cycle and safety performance of the battery. A separator with excellent performance plays an important role in improving the overall performance of the battery. The main function of the diaphragm is to separate the positive and negative electrodes of the battery, prevent the two electrodes from contacting and short circuit, and also have the function of allowing electrolyte ions to pass through. The separator material is non-conductive, and its physical and chemical properties have a great inf...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M50/406H01M50/491H01M50/411H01M10/052
CPCH01M10/052Y02E60/10
Inventor 张德顺胡伟何祥燕吴磊李汪洋徐凤锦张林成郭浩贺云郭志轩
Owner JIESHOU CITY TIANHONG PACKAGING MATERIAL