Porous laminate film, separator for electricity storage device, and electricity storage device

• Main Authors: OHKURA MASATOSHI, ISHIDA YASUYUKI, HIGASHIOJI TAKUJI, WAKAHARA YOKO
• Format: Patent
• Language: English
• Published: 06.05.2015
• Subjects: AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F,C08G; BASIC ELECTRIC ELEMENTS; CHEMISTRY; COMPOSITIONS BASED THEREON; ELECTRICITY; GENERAL PROCESSES OF COMPOUNDING; LAYERED PRODUCTS; LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT ORNON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; PERFORMING OPERATIONS; PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSIONOF CHEMICAL INTO ELECTRICAL ENERGY; THEIR PREPARATION OR CHEMICAL WORKING-UP; TRANSPORTING; WORKING-UP

Provided are a porous laminate film, which has high gas permeability, flatness and heat resistance, achieves a balance between the excellent workability and battery performance and the safety at a high level, and is suitable for a separator for an electricity storage device; and a separator for said electricity storage device. The porous laminate film comprises a polyolefin porous film and a porous layer laminated on at least one main surface of the polyolefin porous film, wherein the porous layer contains binder and heat-resistant particles having the aspect ratio of 1.5 to 10, and the time variant Ps as defined by formula (1) is 1.0 to 1.4 in terms of its cross-sectional shape perpendicular to the major axis, wherein Ps = Rl/Rs ... (1), Rl is the radius of minimum circumscribed circle, and Rs is the radius of the maximum inscribed circle.