The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 29, 2017
Filed:
Dec. 07, 2012
Sekisui Chemical Co., Ltd., Osaka, JP;
Shotaro Kobaru, Osaka, JP;
Yuki Sakurai, Osaka, JP;
SEKISUI CHEMICAL CO., LTD., Osaka, JP;
Abstract
The present invention provides a propylene-based resin microporous film which has excellent electrolyte solution retention property, and can provide a lithium ion battery in which a decrease in discharge capacity is highly reduced even after repeated charge and discharge. The propylene-based resin microporous film is a propylene-based resin microporous film having micropores, wherein a propylene-based resin having a weight average molecular weight of 250,000 to 500,000, a melting point of 160 to 170° C., and a pentad fraction of 96% or more is contained, the surface aperture ratio is 27 to 42%, the ratio of a surface aperture ratio to a porosity is 0.6 or less, and the degree of gas permeability is 50 to 400 s/100 mL.