Microporous polyolefin laminated diaphragm for lithium-ion battery and its production

A technology of lithium-ion batteries and manufacturing methods, which is applied to battery pack parts, circuits, electrical components, etc., can solve problems such as low safety, high safety, and low temperature, and achieve good safety effects

Inactive Publication Date: 2007-01-17
SHENGCHAO AUTOMATION SCI & TECH SHANGHAI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although polyethylene has a low melting point, compared with polypropylene, its early closure characteristics, that is, lower closed cell temperature and higher resistance after closed cell (the increase in resistance after closed cell is about 10% higher than that at room temperature) 3 orders of magnitude), making polyethylene suitable for lithium-ion battery separators, so it is mainly used in current lithium-ion batteries, but in PE alone (ultra-high molecular weight PE, HDPE, ultra-high molecular weight PE and HDPE The microporous membrane made of the mixture) has a low temperature at which the micropores disappear, and its membrane rupture temperature is also low, so it cannot be considered to be safe.
The microporous membrane made of polypropylene alone is less safe because of the higher temperature at which the micropores disappear.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] The proportion of 30% by weight of polypropylene (M w =4.8×10 5, Melt index is 2.1, melting point is 168℃) is added to one of the twin-screw extruders (Φ58mm, L / D=48, high-shear form), and 70% of the weight unit ratio of liquid paraffin is added through lateral feeding Twin-screw extruder, by melting polypropylene at 220°C and 200rpm in the twin-screw extruder and mixing with liquid paraffin to form a polypropylene solution, the resulting solution is transferred from the two surface layers of the three-layer die through a metering pump Extrusion, the thickness of each layer is 15μm.

[0028] At the same time, 30% weight unit proportion of high-density polyethylene (ρ = 0.968g / cm 3 , M w =3.0×10 5 ) Add another twin-screw extruder (Φ58mm, L / D=48, high-shear form), and 70% of the weight unit ratio of liquid paraffin is added to the twin-screw extruder through lateral feeding. In the screw extruder, the polyethylene was melted and mixed with liquid paraffin at 220° C. and 200 ...

Embodiment 2

[0031] The 20% weight unit proportion of polypropylene (M w =4.8×10 5 , Melt index is 2.1, melting point is 168℃) is added to one of the twin-screw extruders (Φ58mm, L / D=48, high shear mode), and 80% of the weight unit ratio of liquid paraffin is added to it through lateral feeding Twin-screw extruder, by melting polypropylene at 220°C and 200rpm in the twin-screw extruder and mixing with liquid paraffin to form a polypropylene solution, the resulting solution is transferred from the two surface layers of the three-layer die through a metering pump Extrusion, the thickness of each layer is 15μm. The die lip gap is 1.5mm, and the die head heating temperature is 220℃

[0032] At the same time, the 20% weight unit proportion of high-density polyethylene (ρ = 0.958g / cm 3 , M w =6.8×10 5 ) Is added to a twin-screw extruder (Φ58mm, L / D=48, high-shear form), and 80% of the weight unit ratio of liquid paraffin is added to the twin-screw extruder through lateral feeding and extruded by the...

Embodiment 3

[0035] The 10% weight unit proportion of polypropylene (M w =4.8×10 5 , Melt index is 2.1, melting point is 168℃) is added to one of the twin-screw extruders (Φ58mm, L / D=48, high-shear form), and 90% weight unit proportion of decane is added to it through lateral feeding Twin-screw extruder, by melting polypropylene at 220°C and 200rpm in the twin-screw extruder and mixing with liquid paraffin to form a polypropylene solution, the resulting solution is transferred from the two surface layers of the three-layer die through a metering pump Extrusion, the thickness of each layer is 15μm. The die lip gap is 1mm, and the die head heating temperature is 180℃

[0036] At the same time, the 10% weight unit ratio of high-density polyethylene (ρ = 0.968g / cm 3 , M w =3.0×10 5 ) Add another twin-screw extruder (Φ58mm, L / D=48, high-shear form), and 90% of the weight unit ratio of decane is added to the twin-screw extruder through lateral feeding. In the screw extruder, the polyethylene was mel...

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Abstract

The invention is concerned with the poly tiny porous multilayer septa for lithium ion battery, including several polyethylene layers and several polypropylene layers that cling at the polyethylene layers. The poly tiny porous multilayer septa manufacture method for lithium ion battery includes the following steps: mixes the polyethylene and the polypropylene with the high boiling-point small molecular weight compound solvent respectively, fusing plastifies the solution; extrudes the filming slice from the solution respectively using the double screw by the multi-layer die-head altogether, the cooling film forms the multi-layer gelatinous compound; heats and stretches the compound bidirectionally, cleans the solvent in the compound, dries the compound, and processes the heating finalize the design. The invention uses the whole structure compounding by the multi-layer poly film, the film is with the lower closing temperature by the low melting point polyethylene layer, the film is with the higher breaking temperature by the high melting point polypropylene layer.

Description

Technical field [0001] The invention relates to a polyene microporous diaphragm, in particular to a polyene microporous multilayer diaphragm for lithium ion batteries and a manufacturing method thereof. Background technique [0002] In 1991, SONY successfully launched the first commercial lithium-ion battery, leading to a new generation of rechargeable batteries. Lithium-ion batteries are currently widely used in portable electronic products, especially notebook computers and mobile phones. Compared with nickel-cadmium batteries and nickel-hydrogen batteries, lithium-ion batteries have the advantages of high energy density, long life and high voltage. The composition of the lithium ion battery includes: lithium oxide positive stage, carbon negative electrode, polymer separator and electrolyte. Among them, there is a membrane material between the positive electrode and the negative electrode of the lithium ion battery, which is usually called a separator, which is an important par...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/16H01M2/14C08J5/22C08J9/00H01M50/403H01M50/417H01M50/449H01M50/457H01M50/491
CPCY02E60/12Y02E60/10
Inventor 彭海生郑燃
Owner SHENGCHAO AUTOMATION SCI & TECH SHANGHAI
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