Multilayer micro-porous polyolefin diaphragm and production method thereof

A technology of microporous diaphragm and polyolefin, applied in electrical components, electrochemical generators, circuits, etc., can solve the problems of poor dimensional stability of composite microporous membranes at high temperature, and achieve improved battery safety, uniform pore size distribution, and closed cells Effect of increasing temperature and membrane rupture temperature

Active Publication Date: 2018-03-16
GUANGDONG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the prepared composite microporous membrane has poor dimensional stability at high temperature.

Method used

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  • Multilayer micro-porous polyolefin diaphragm and production method thereof
  • Multilayer micro-porous polyolefin diaphragm and production method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0044] Adding nanoparticles and polyethylene to a twin-screw extruder for melt blending to prepare inorganic composite polyethylene raw materials, the polyethylene is high-density polyethylene, and the melt index is 0.5g / 10min; the nanoparticles are magnesium sulfate; The particle size of the nanoparticles is 2-50nm, and the blending mass fraction is 20%.

[0045]Add homopolypropylene with a melt index of 1g / 10min and the above-mentioned inorganic composite polyethylene materials into different extruders respectively, co-extrude through a multi-layer die, and cast to obtain three layers of PP-PE / nanoparticle-PP polyolefin membrane. The extruder die temperature for extruding polypropylene resin is 190°C, the extruder die temperature for extruding inorganic composite polyethylene is 180°C, and the multilayer die temperature is 190°C. The casting temperature was 80° C., and the casting film thickness was 20 μm. Heat treatment in a blast oven at 125°C for 0.5h. Cold drawing at ...

Embodiment 2

[0047] Add nanoparticles and polyethylene to a twin-screw extruder for melt blending to prepare inorganic composite polyethylene raw materials, the polyethylene is high-density polyethylene, and the melt index is 2g / 10min; the nanoparticles are magnesium sulfate; The particle size of the nanoparticles is 100-200nm, and the blending mass fraction is 20%.

[0048] Add the homopolypropylene with a melt index of 5g / 10min and the above-mentioned inorganic composite polyethylene materials into different extruders, co-extrude through a multi-layer die, and cast to obtain a three-layer PP-PE / nanoparticle-PP polyolefin membrane. The extruder die temperature for extruding polypropylene resin is 230°C, the extruder die temperature for extruding inorganic composite polyethylene is 210°C, and the multilayer die temperature is 230°C. The casting temperature is 80°C, and the casting film thickness is 20um. Heat treatment in a blast oven at 125°C for 0.5h. Cold drawing at -20°C with a stre...

Embodiment 3

[0050] Add nanoparticles and polyethylene to a twin-screw extruder for melt blending to prepare inorganic composite polyethylene raw materials, the polyethylene is high-density polyethylene, and the melt index is 0.5g / 10min; the nanoparticles are titanium dioxide; The particle size of the nanoparticles is 300-500nm, and the blending mass fraction is 15%.

[0051] Add the homopolypropylene with a melt index of 5g / 10min and the above-mentioned inorganic composite polyethylene materials into different extruders, co-extrude through a multi-layer die, and cast to obtain a three-layer PP-PE / nanoparticle-PP polyolefin membrane. The extruder die temperature for extruding polypropylene resin is 200°C, the extruder die temperature for extruding inorganic composite polyethylene is 200°C, and the multilayer die temperature is 210°C. The casting temperature is 80°C, and the casting film thickness is 20um. Heat treatment in a blast oven at 125°C for 0.5h. Cold drawing at -20°C with a str...

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Abstract

The invention provides a production method of a multilayer micro-porous polyolefin diaphragm. The method comprises the following steps: 1, respectively carrying out melt extrusion on polypropylene andinorganic composite polyethylene through adopting three extrusion casting machines, and carrying out multilayer bush die casting to obtain a multilayer composite cast film, wherein the polypropyleneis positioned at the outer layer, and the inorganic composite polyethylene is positioned at the middle layer; 2, carrying out heat treatment on the multilayer composite cast film at 125 DEG C for 0.5h to obtain a multilayer heat-treated film; 3, carrying out cold drawing on the multilayer heat-treated film at -20 DEG C under a drawing ratio of 50% to obtain a heat-treated film having initial porous nucleuses; 4, carrying out hot drawing on the heat-treated film having initial porous nucleuses at 125 DEG C under a drawing ratio of 90%; and 5, fixing the micro-porous film obtained in step 4 at125 DEG C for 20 min in order to obtain the multilayer micro-porous polyolefin diaphragm. The produced micro-porous diaphragm has the advantages of uniform aperture, good heat resistance and good stability.

Description

technical field [0001] The invention relates to the technical field of isolation membrane production, in particular to a multilayer polyolefin microporous membrane and a preparation method thereof. Background technique [0002] The separator is the core component of the lithium-ion battery, accounting for about 18%-30% of the cost of the entire lithium battery. The quality of its performance plays a vital role in the overall performance of lithium batteries, and it is also one of the key technologies restricting the development of lithium batteries. With the development of electronic products and the expansion of application fields, people's requirements for the performance of lithium batteries are also getting higher and higher. In order to meet the development requirements of lithium batteries, the separator should have high mechanical strength, excellent thermal stability, good micropore distribution and low manufacturing cost. [0003] At present, lithium-ion battery s...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/14H01M2/16H01M10/0525H01M50/403H01M50/417H01M50/431H01M50/443H01M50/446H01M50/457H01M50/489H01M50/586
CPCH01M10/0525H01M50/431H01M50/403H01M50/411Y02E60/10
Inventor 谢嘉宜田子钦徐睿杰雷彩红
Owner GUANGDONG UNIV OF TECH
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