Sk Innovation Co., Ltd.

Sk Energy Co., Ltd.

Sk Ie Technology Co., Ltd.

Gwigwon Kang

Youngkeun Lee

Hyungmin Kim

Jang-weon Rhee

Inhwa Jung

Yongkyoung Kim

Yong Kyoung Kim

Sangbae Cheong

Dongjin Joo

Jaewoong Kim

Jungmoon Sung

Youngjun Woo

Jang-Weon Rhee

Provided is a manufacturing method of a polyolefin-based multilayer composite porous film, including: a) forming a composition including a polyolefin resin and diluent to a sheet; b) stretching the sheet and extracting the diluent to manufacture a film; c) performing heat-treatment on the manufactured film; and d) coating one surface or both surfaces of the heat-treated film with a coating solution containing a heat resistant resin, wherein step c) and step d) are continuously performed.

Manufacturing method of porous multilayered polyolefin

The present invention relates to a multi-layered microporous polyolefin film for a battery separator and a method for preparing the same. The microporous multi-layered film of the present invention has a characteristics to have both the low shutdown temperature conferred by the polyethylene and the high melt fracture temperature conferred by the polypropylene and heat-resistant filler. In addition, it has the high strength and stability conferred by the micropores prepared under wet process and the high permeability and high strength conferred by the macropores prepared under dry process. Therefore, this multi-layered film can be used effectively to manufacture a secondary battery with high capacity and high power.

Microporous polyolefin multi layer film and preparing method thereof

Microporous polyolefin multi layer film

The present invention relates to a microporous polyethylene film for use as battery separator. The microporous polyethylene film according to the present invention is characterized by having a film thickness of 5-40 &#x3bc;m, a porosity of 35-55%, a permeability from 2.5&#xd7;10to 10.0 10Darcy, a puncture strength of at least 0.10 N/&#x3bc;m at 90&#xb0; C., a puncture angle of at least 30&#xb0; at 90&#xb0; C., and a permeability from 2.0 10to 8.0 10Darcy after shrinking freely at 120&#xb0; C. for 1 hour. The microporous polyethylene film in accordance with the present invention has very superior puncture strength and thermal stability at high temperature and takes place of less decrease of permeability due to low thermal shrinkage at high temperature, as well as superior permeability. Therefore, it can be usefully applied in a high-capacity, high-power battery to improve thermal stability and long-term stability of the battery.

Microporous polyethylene film with good property of strength and permeability at high temperature

The present invention relates to a microporous polyolefin film suitable as a separator for batteries and thermal properties thereof. A microporous polyolefin film according to the present invention has a film thickness of 5-40 &#x3bc;m, a porosity of 30%-60%, a permeability of 2.0&#xd7;10-8.0&#xd7;10Darcy, a maximum pore size determined by the bubble point method of not more than 0.1 &#x3bc;m, a puncture strength of 0.20 N/&#x3bc;m or more at room temperature and 0.05 N/&#x3bc;m or more at 120&#xb0; C., and a maximum shrinkage ratio in the transverse direction (TD) when subjected to a thickness-normalized external force in TMA (thermo-mechanical analysis) of not more than 0%. With excellent thermal stability at high temperature as well as superior puncture strength and gas permeability, the microporous polyolefin film according to the present invention is suitable for high-capacity, and high-power batteries.

Microporous polyolefin film possessing good mechanical properties and thermal stability

Growing community of inventors

Daejeon, South Korea

Gwigwon Kang