Method of manufacturing the microporous polyolefin composite film with a thermally stable layer at high temperature

A manufacturing method, polyolefin microporous membrane technology, applied in chemical instruments and methods, membrane technology, semi-permeable membrane separation, etc., can solve problems such as limitations, poor quality uniformity, and improved heat resistance of the diaphragm

Inactive Publication Date: 2011-04-13
SK INNOVATION CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, it is difficult to provide effective permeability by a pore-forming method in which a single resin is phase-separated by a dry process when forming a coating layer of a membrane
Furthermore, since the phase separation scale and uniformity vary significantly with drying conditions such as humidity and temperature, there are limitations in fabricating separators with uniform quality
[0012] With regard to heat resistance, which is one of the main characteristics of battery separators, conventional methods have limitations in the heat resistance of the resin itself, or application of a heat-resistant resin cannot contribute to the improvement of the heat resistance of the separator
In addition, other physical properties such as gas permeability are poor or not mentioned, and the quality uniformity is also poor
In addition, when a separator manufactured by a conventional method is actually applied to a battery, there is a problem that constant thermal stability cannot be provided under conditions such as high temperature, high voltage, and organic electrolyte

Method used

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  • Method of manufacturing the microporous polyolefin composite film with a thermally stable layer at high temperature
  • Method of manufacturing the microporous polyolefin composite film with a thermally stable layer at high temperature
  • Method of manufacturing the microporous polyolefin composite film with a thermally stable layer at high temperature

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Experimental program
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Effect test

Embodiment 1

[0114] The composition was extruded at a temperature of 240° C. using a twin-screw compounder having a T-die, and passed through a zone in which the temperature was set at 180° C. to induce phase separation, and then a sheet was prepared using a casting roll. The sheet was prepared by a continuous biaxial stretching method, wherein the stretching ratio was 6 times in both MD and TD, and the stretching temperature was 121°C. Here, the heat-setting temperature is 128° C., and the heat-setting width is 1-1.2-1.1. The final membrane has a thickness of 16 μm and a gas permeability of 3.5×10 -5 Darcy.

[0115] A coating-forming solution was prepared by dissolving polycarbonate having a melting point of 231° C. in a DMF solvent. In the composition of the solution, resin / solvent was 13 / 87 (% by weight). Coat one surface by rod coating. The coated film was dried in a 50°C oven for 3 minutes, impregnated with an ethanol non-solvent, and then dried in a 60°C oven for 30 minutes.

[...

Embodiment 2

[0119] Scanning electron micrographs showing the surface of the fabricated microporous polyolefin composite membrane as figure 2 shown.

[0120] [Example 3]

Embodiment 3

[0122] [Example 4]

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Abstract

Provided is a method of manufacturing a microporous polyolefin composite film with a thermally stable porous layer at high temperature, particularly, to a method of manufacturing a microporous polyolefin composite film with a thermally stable porous layer at high temperature, comprising preparing a polyolefin microporous film using a composition containing a polyolefin resin; coating a solution, in which a high heat-resistant resin is dissolved in a solvent, on one surface or both surfaces of the polyolefin microporous film; phase-separating the polyolefin microporous film coated with the solution by contacting with a nonsolvent after the coating; and drying the polyolefin microporous film so as to remove the solvent and nonsolvent remained after the phase-separating, and thus forming the thermally stable layer at high temperature.

Description

technical field [0001] The invention relates to a method for manufacturing a microporous polyolefin composite membrane with excellent permeability and excellent thermal stability in high-temperature electrolytes. Background technique [0002] Polyolefin-based microporous membranes are widely used as battery separators, membrane filters and membranes for microfiltration because of their chemical stability and excellent physical properties. Among them, for the battery separator, the microporous structure needs to have a space separation function between the positive electrode and the negative electrode and a microporous structure suitable for high ion conductivity. Recently, in view of the development trend of secondary batteries toward high capacity and high power, it is also required to enhance the characteristics of the thermal stability and electrical stability of the separator during charging and discharging of the secondary battery. In the case of a lithium secondary ba...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/16H01M50/417H01M50/451H01M50/457H01M50/489H01M50/491H01M50/494
CPCH01M2/166H01M10/052H01M2/1653Y02E60/12H01M2/1686Y10T428/2495Y02E60/10H01M50/446H01M50/417H01M50/489H01M50/451H01M50/457H01M50/491H01M50/494B01D69/12B01D71/00
Inventor 李济安成贞文金容庆李荣根
Owner SK INNOVATION CO LTD
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