Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

High temperature-resistant co-extrusion unidirectional stretching microporous diaphragm preparation method and microporous diaphragm

A technology of unidirectional stretching and microporous diaphragms, which is applied in the direction of separators/films/diaphragms/spacers, electrical components, circuits, etc., which can solve the problems of limited matrix adhesion, poor extrusion processing performance, and inorganic powders. Eliminate problems such as shedding, achieve the effects of increased closed cell temperature and membrane rupture temperature, good high temperature resistance, and uniform pore size distribution

Active Publication Date: 2018-03-27
GUANGDONG UNIV OF TECH
View PDF4 Cites 1 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This type of method uses the heat resistance of high-temperature resistant polymers to improve the performance of instantaneous thermal shock resistance, but the uniformity of pores obtained by electrospinning and coating methods is poor, and the adhesion to the substrate is limited, which will cause problems during long-term cycling. Formation of lithium dendrites endangers battery safety
[0005] Another technical method is to coat an inorganic layer on the surface of the polyolefin diaphragm, and use the inorganic layer to improve the dimensional stability of the polyolefin diaphragm at high temperature and improve the safety of the diaphragm, but the thickness of the inorganic coating is only 2- 3 microns, safety is still difficult to guarantee under instantaneous thermal shock at high temperature
At the same time, the inorganic powder is bonded to the surface of the separator with a polymer binder, which will cause the inorganic powder to fall off and dissociate under long-term immersion in the electrolyte, and the impact on battery safety is not yet clear.
[0006] At present, there is still the technology of producing polyolefin porous membrane by melt stretching method, but the material characteristics of polyolefin itself cannot meet the needs of high heat resistance lithium battery separator
Another study shows that using semi-crystalline high-temperature-resistant materials instead of existing polyolefin materials to co-extrude composite diaphragms can fundamentally solve the problem of heat resistance. However, due to the poor extrusion processing performance of materials, only a single layer Extrusion, separation of film layers due to interlaminar shear of different melts and control of initial lamella structure, the use of semi-crystalline high-temperature resistant materials to prepare multilayer microporous separators has not been reported so far

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] Add polyphenylene sulfide with a melt index of 3g / 10min and polytetramethylpentene with a melt index of 5g / 10min into different extruders, and co-extrude through a multi-layer die. The end-stage temperatures of the methyl-pentene layer casting machine were 280°C and 230°C respectively, the die head temperature was 290°C, the casting roll temperature was 120°C, and the melt draw ratio was 1.5. A composite cast film of phenylene sulfide / polytetramethylpentene / polyphenylene sulfide, wherein the rotational speed of the screw of the polytetramethylpentene layer is 40 rpm, and the rotational speed of the screw of the polyphenylene sulfide layer is 20 rpm. Heat treatment at 180° C. for 0.3 h to obtain a multilayer heat treatment film. One-stage stretching was carried out at 150°C with a stretching rate of 5mm / min and a stretching ratio of 20%, followed by two-stage stretching at 220°C with a stretching rate of 50mm / min and a stretching ratio of 100%. The heat setting temperat...

Embodiment 2

[0038] Add polyphenylene sulfide with a melt index of 8g / 10min and polytetramethylpentene with a melt index of 30g / 10min into different extruders, and co-extrude through a multi-layer die. The end-stage temperatures of the methyl-pentene layer casting machine were 290°C and 260°C respectively, the die head temperature was 290°C, the casting roll temperature was 180°C, and the melt draw ratio was 20. A composite cast film of phenylene sulfide / polytetramethylpentene / polyphenylene sulfide, wherein the rotational speed of the screw of the polytetramethylpentene layer is 60 rpm, and the rotational speed of the screw of the polyphenylene sulfide layer is 40 rpm. Heat treatment at 220° C. for 2 hours to obtain a multilayer heat-treated film. One-stage stretching was performed at 180°C with a stretching rate of 50mm / min and a stretching ratio of 80%, followed by two-stage stretching at 240°C with a stretching rate of 150mm / min and a stretching ratio of 120%. The heat setting temperat...

Embodiment 3

[0040]Add polyphenylene sulfide with a melt index of 5g / 10min and polytetramethylpentene with a melt index of 10g / 10min into different extruders, and co-extrude through a multi-layer die. The end-stage temperatures of the methyl-pentene layer casting machine were 280°C and 240°C respectively, the die head temperature was 290°C, the casting roll temperature was 150°C, and the melt draw ratio was 10. A composite cast film of phenylene sulfide / polytetramethylpentene / polyphenylene sulfide, wherein the rotational speed of the screw of the polytetramethylpentene layer is 50 rpm, and the rotational speed of the screw of the polyphenylene sulfide layer is 30 rpm. Heat treatment at 200° C. for 0.8 h to obtain a multilayer heat treatment film. One-stage stretching was performed at 180°C with a stretching rate of 50mm / min and a stretching ratio of 80%, followed by two-stage stretching at 240°C with a stretching rate of 150mm / min and a stretching ratio of 120%. The heat setting temperatu...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

PropertyMeasurementUnit
melt flow indexaaaaaaaaaa
melt flow indexaaaaaaaaaa
membrane rupture temperatureaaaaaaaaaa
Login to View More

Abstract

The invention provides a high temperature-resistant co-extrusion unidirectional stretching microporous diaphragm preparation method. The method comprises the following steps: A) employing three extrusion casting-film machines and respectively performing melt extrusion to obtain polyphenylene sulfide and polytetramethyl isopentene resin, and obtaining a multilayer composite casting film through multilayer neck die tape casting, wherein polyphenylene sulfide is posited at an outer layer, and polytetramethyl isopentene resin is positioned at a middle layer; B) performing heat treatment on the multilayer composite casting film at the temperature of 180-220 DEG C for 0.3-2 h to obtain a multilayer heat treatment film; C) at the temperature of 150-180 DEG C, performing first segment stretching on the multilayer heat treatment film, wherein stretching multiplying power is 20-80%; D) at the temperature of 220-240 DEG C, performing second segment stretching on the multilayer heat treatment film, wherein stretching multiplying power is 100-120%; and E) fixing the microporous film after second segment stretching at the temperature of 240-250 DEG C for 1-5 min to obtain the microporous diaphragm. The microporous diaphragm has the advantages of uniform structure and high temperature resistance.

Description

technical field [0001] The invention relates to the technical field of separator production, in particular to a preparation method of a high-temperature-resistant co-extruded uniaxially stretched microporous diaphragm and the microporous diaphragm. Background technique [0002] The diaphragm is the core component of the lithium-ion battery, accounting for about 18%-30% of the cost of the entire lithium battery. Its performance plays a vital role in the overall performance of the lithium battery. With the development of power batteries, the rapid The requirements for charging technology and battery cycle performance under high magnification are increasing day by day, and the danger of battery explosion caused by battery self-heating is becoming more and more prominent. High temperature resistant and high safety lithium battery separator has become an urgent need in the industry. [0003] At present, lithium-ion battery separators are mainly crystalline polyolefin materials su...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/14H01M2/18H01M50/403H01M50/411H01M50/417H01M50/449H01M50/457H01M50/491
CPCH01M50/403H01M50/463Y02E60/10
Inventor 徐睿杰谢嘉宜雷彩红
Owner GUANGDONG UNIV OF TECH
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic, Popular Technical Reports.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com