Compound modified polyolefin lithium ion battery separator and manufacturing method thereof

A technology of ion battery and compound modification, which is applied in battery components, chemical instruments and methods, circuits, etc., can solve the problems of reduced overall battery performance and safety, limited temperature resistance, poor electrolyte affinity, etc.

Inactive Publication Date: 2012-01-04
CANGZHOU MINGZHU PLASTIC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, polyethylene and polypropylene separators have the disadvantages of poor affinity for electrolytes and limited temperature resistance (usually lower than 150°C), which reduces the overall performance and safety of the battery.

Method used

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  • Compound modified polyolefin lithium ion battery separator and manufacturing method thereof
  • Compound modified polyolefin lithium ion battery separator and manufacturing method thereof
  • Compound modified polyolefin lithium ion battery separator and manufacturing method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] a. Preparation of sol-like polymer: 1g PVDF-HFP (molecular weight 900,000) and 0.2g diameter <50nm, the modified nano-silica with vinyl surface group is dissolved in 45ml of dimethylformamide (DMF) under the protection of N2, the temperature is controlled at 70℃, fully stirred until completely dissolved to form a sol-like polymer ,spare;

[0023] b. Surface pretreatment of polyolefin microporous membrane: corona pretreatment of polypropylene microporous membrane with a thickness of 20μm, machine speed 20m / min, corona power 500W, corona voltage 2-10kV, standby;

[0024] c. Coating film: The sol-like polymer obtained in step a is coated on one side of the polypropylene microporous film after the surface treatment in step b by a coating machine, and the thickness of the single-sided wet coating is controlled to be less than 5 μm, and the coating is wet Thin film battery separator, spare;

[0025] d. Drying to obtain a finished product: Transfer the wet film-coated battery diaphr...

Embodiment 2

[0027] a. Preparation of sol polymer: 1g PVDF-HFP (molecular weight 900,000) and 0.1g diameter <50nm, the modified nano-silica with vinyl surface group is dissolved in 40ml dimethylformamide (DMF) under the protection of N2, the temperature is controlled at 100℃, fully stirred until completely dissolved, forming a sol-like polymer ,spare;

[0028] b. Surface pretreatment of polyolefin microporous membrane: corona pretreatment of polyethylene microporous membrane with a thickness of 20μm, machine speed 20m / min, corona power 500W, corona voltage 2-10kV, standby;

[0029] c. Film coating: the sol-like polymer obtained in step a is coated on one side of the polyethylene microporous film after surface treatment in step b by a coating machine, and the thickness of the single-sided wet coating is controlled to be less than 5μm, and the coating is wet Thin film battery separator, spare;

[0030] d. Dry the finished product: Transfer the wet film-coated battery diaphragm obtained in step c ...

Embodiment 3

[0032] a. Preparation of sol-like polymer: 1g PVDF-HFP (molecular weight 900,000) and) 0.05g diameter <50nm, the modified nano-silica with vinyl surface group is dissolved in 40ml dimethylformamide (DMF) under the protection of N2, the temperature is controlled at 60℃, fully stirred until completely dissolved, forming a sol-like polymer ,spare;

[0033] b. Surface pretreatment of polyolefin microporous film: a three-layer composite film of polypropylene microporous film / polyethylene microporous film / polypropylene microporous film with a thickness of 40μm is subjected to corona pretreatment at a speed of 20m / min, Corona power 500W, corona voltage 2~10kV, spare;

[0034] c. Coated film: Coat the sol-like polymer obtained in step a on one side of the three-layer composite film after surface treatment in step b by a coating machine, and control the thickness of the single-sided wet coating to be less than 5μm, so that the wet film is coated Battery separator, spare;

[0035] d. Drying ...

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Abstract

The invention provides a compound modified polyolefin lithium ion battery separator and a manufacturing method thereof. The battery separator is formed by compounding a one-sided or double-sided polyolefin microporous membrane with a layer of thin film, wherein the thin film is formed by dissolving a polymer and inorganic fillers in a solvent; the polymer is polyvinylidene fluoride-hexafluoropropylene, and the inorganic fillers are oxides; and the weight ratio of the polymer to the inorganic fillers is 100:(2-30). The battery separator prepared by the method provided by the invention has the advantages of good wettability, thermal blackout effect and low heat shrinkage, thus the interfacial characteristics between the cathode and anode materials and the separator can be improved, and the safety performance and cycle performance of the battery can be enhanced.

Description

Technical field [0001] The invention relates to an improved polyolefin lithium ion battery diaphragm and a preparation method thereof, and belongs to the application field of energy storage devices such as batteries and capacitors. Background technique [0002] Battery separator refers to the polymer separator between the positive and negative electrodes of lithium-ion batteries. It is one of the most critical parts of lithium-ion batteries and has a direct impact on battery safety. Its functions are: to isolate the positive and negative electrodes and prevent the electrons in the battery from freely passing through; and to allow the ions in the electrolyte to pass freely between the positive and negative electrodes. The function of the battery separator to isolate the positive and negative electrodes enables the battery to limit the increase in current when the battery is overcharged or the temperature rises, preventing the battery from short-circuiting or even exploding, and ha...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/16B32B27/32
CPCY02E60/10
Inventor 赵久艳谷传明徐长城
Owner CANGZHOU MINGZHU PLASTIC
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