Polyolefin multi-layer porous diaphragm for lithium ion battery and preparation method thereof

A technology of lithium-ion batteries and porous diaphragms, which can be applied to battery components, chemical instruments and methods, circuits, etc., can solve the problems of large thermal shrinkage rate at 120°C, unfavorable applications, and difficult application of membrane rupture temperature in the field of power batteries. Achieve the effect of increasing the rupture temperature, excellent safety performance, and conducive to continuous production

Inactive Publication Date: 2011-05-18
FOSHAN JINHUI HIGH TECH OPTOELECTRONICS MATERIAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the rupture temperature of this separator is still difficult to apply to the field of power batteries, and the th

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] First, weigh 5 parts of nano-calcium carbonate and 100 parts of isopropanol by weight, stir and disperse evenly at 80°C, then add 5 parts of sodium stearate into the dispersion system, react for three hours and then vacuum pump The solvent isopropanol is removed by filtration, and the solid residue obtained by filtration is dried, ground and pulverized to obtain modified nano-calcium carbonate. Then, the modified nano-calcium carbonate and liquid paraffin are fully mixed and dispersed at a high speed in a ratio of 1:50 to make a paraffin oil mixed solution.

[0018] Mix 25% by weight polypropylene with 0.5% antioxidant and 0.5% nucleating agent in a high-speed mixer, then add it to a twin-screw extruder, and feed 75% of the paraffin oil mixed solution through a side feed The material is injected into the twin-screw extruder, and the polypropylene is melt-blended with the diluent solution at 230°C to form a polypropylene solution, and the obtained solution is extruded fr...

Embodiment 2

[0022] First, weigh 5 parts of nano-silica and 100 parts of ethanol by weight, stir and disperse evenly at 80°C, then add 10 parts of hexamethyldisilazane (HMDS) into the dispersion system, and react two The solvent ethanol is removed by vacuum filtration after a small period of time, and the solid residue obtained by filtration is dried, ground and pulverized to obtain modified nano silicon dioxide. Then the modified nano-silica and liquid paraffin are fully mixed and dispersed at a high speed in a ratio of 1:50 to make a paraffin oil solution.

[0023] Mix 25% by weight polypropylene with 0.5% antioxidant and 0.5% nucleating agent in a high-speed mixer, then add it to a twin-screw extruder, and feed 75% of the paraffin oil solution through side feeding Inject into a twin-screw extruder to melt and blend polypropylene with a diluent solution at 240°C to form a polypropylene solution. The obtained solution is extruded from the two surface layers of a three-layer die under the ...

Embodiment 3

[0027] First, weigh 5 parts of nano-alumina and 100 parts of ethanol according to the weight ratio, stir and disperse evenly at 80°C, then add 5 parts of aluminate coupling agent to the dispersion system, and after two hours of reaction, vacuum pump The solvent ethanol is removed by filtration, and the solid residue obtained by filtration is dried, ground and pulverized to obtain modified nano-alumina. Then the modified nano-alumina and liquid paraffin are fully mixed at a high speed in a ratio of 1:70 and dispersed evenly to make a paraffin oil mixed solution.

[0028] Mix 20% by weight polypropylene with 0.5% antioxidant and 0.5% nucleating agent in a high-speed mixer, then add it to a twin-screw extruder, and feed 80% of the paraffin oil mixed solution through a side feed The material is injected into the twin-screw extruder, and the polypropylene is melt-blended with the diluent solution at 230°C to form a polypropylene solution, and the obtained solution is extruded from ...

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PUM

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Abstract

The invention discloses a diaphragm used for preparing a lithium ion battery. The diaphragm is multilayer material formed by a polyethylene layer and a polypropylene layer which are mutually overlapped, wherein each layer is added with a heat resistant material. The preparation method of the porous diaphragm used for preparing the lithium ion battery comprises the following steps: firstly modifying the surface of a heat resistant inorganic material, uniformly mixing the inorganic material with high boiling point diluent, respectively adding polyethylene and polypropylene as well as the high boiling point diluent mixed with the inorganic material and other auxiliaries into a double screw extruder to be fully plasticized and extruded, preparing a uniform multilayer diaphragm by virtue of a multilayer die head under the control of a metering pump, and carrying out biaxial orientation stretching, washing and extracting, thus the porous diaphragm is obtained. The diaphragm prepared by the invention has higher air permeability and higher anti-puncture strength, more importantly, diaphragm rupturing temperature is higher, obturator temperature is lower, and shrinkage rate is lower, thus the diaphragm prepared by the invention is a novel diaphragm used for the lithium ion battery and has excellent properties.

Description

technical field [0001] The invention relates to a polyolefin multilayer porous diaphragm for lithium ion batteries and a preparation method thereof. Background technique [0002] Since Sony launched the first commercial lithium-ion battery in 1991, rechargeable batteries have made great progress in the world. Due to its advantages such as high energy density, long life, high voltage, and rechargeable cycles, the application fields of lithium-ion batteries continue to expand. In recent years, as the international community has paid more and more attention to global warming, and the Copenhagen Conference has imposed greenhouse gas emission reduction requirements for various countries, the new energy power battery sector has ushered in unprecedented development opportunities, and the future market prospect is very clear. The lithium-ion battery separator is an important part of the lithium-ion battery, which plays the role of isolating the positive and negative electrodes of t...

Claims

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Application Information

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IPC IPC(8): H01M2/14H01M2/18B32B27/32
CPCY02E60/12Y02E60/10
Inventor 王松钊吴耀根蔡朝辉
Owner FOSHAN JINHUI HIGH TECH OPTOELECTRONICS MATERIAL
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