MICROPOROUS POLYOLEFIN MEMBRANE AND NONAQUEOUS ELECTROLYTE SECONDARY BATTERIES

• Main Authors: NAKAJIMA RYUTA, WATANABE MITSURU, ISHIHARA TAKESHI, FUJIWARA SATOSHI, TOYODA NAOKI, SAKAMOTO MITSUTAKA
• Format: Patent
• Language: English; Japanese
• Published: 18.02.2021
• Subjects: AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F,C08G; BASIC ELECTRIC ELEMENTS; CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES ORLIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE; CHEMISTRY; COMPOSITIONS BASED THEREON; ELECTRICITY; GENERAL PROCESSES OF COMPOUNDING; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSIONOF CHEMICAL INTO ELECTRICAL ENERGY; THEIR PREPARATION OR CHEMICAL WORKING-UP; WORKING-UP

To provide a microporous polyolefin membrane having improved output properties, strength, and shrinkage rates.SOLUTION: The present invention relates to a microporous polyolefin membrane in which: a shrinkage ratio is less than 10% in the MD direction at 105°C/8h; if a 11.7 μm×9.4 μm rectangular field of view of a surface SEM observation image as obtained by observation with a scanning electron microscope (SEM) is divided into 0.5 μm×0.5 μm pieces, the sum of resin areas in the pieces satisfying R2≥R1 (namely, non-opening parts on the surface) is 20 μm2 or less in the 11.7 μm×9.4 μm area of the surface SEM observation image; and a fibril diameter is from 10 to 50 nm.SELECTED DRAWING: None 【課題】本発明は、従来よりも優れた出力特性と強度、収縮率を有するポリオレフィン微多孔膜を提供することを目的とする。【解決手段】本発明は、１０５℃／８ｈのＭＤ方向の収縮率が１０％未満であり、走査型電子顕微鏡（ＳＥＭ）を用いた観察により得られる表面ＳＥＭ観察画像１１．７μｍ×９．４μｍの長方形状の視野を縦横それぞれ０．５μｍ画に分割し、Ｒ２≧Ｒ１の関係を満たす区画中の樹脂面積の総和（表面の未開孔部）が、前記表面ＳＥＭ観察画像１１．７μｍ×９．４μｍにおいて２０μｍ２以下であり、 フィブリル径が１０〜５０ｎｍであるポリオレフィン微多孔膜に関する。【選択図】なし