Japan Vilene Company, Ltd.

National Institute of Advanced Industrial Science and Technology

Te Hyon Cho

Masanao Tanaka

Tatsuo Nakamura

Hiroshi Ohnishi

Yuka Kondo

Tetsuo Sakai

Hiroaki Yamazaki

Koji Kimura

Yoshikazu Miyata

Disclosed are a separator for lithium ion secondary batteries, having an inorganic layer formed from inorganic particles, characterized in that the inorganic particles have a particle diameter distribution in which the 50% cumulative particle diameter Dis in the range of 100 nm to 500 nm, the 10% cumulative particle diameter Dis 0.5Dor more, and the 90% cumulative particle diameter Dis 2Dor less; a method for manufacturing the separator; and a lithium ion secondary battery using the separator. When the separator is used, there can be produced a lithium ion secondary battery in which a short circuit caused by contraction or melting can be definitely prevented, as well as the current density applied to the electrodes during charging and discharging is uniform so that charging and discharging can be efficiently achieved.

Separator for lithium ion secondary battery, method for manufacture thereof, and lithium ion secondary battery

Disclosed is a lithium ion secondary battery, in which comprises a vinyl alcohol polymer or a derivative thereof in an amount of 0.3 mg or more per 1 mAh of battery capacity in terms of a vinyl alcohol unit moiety content. The lithium ion secondary battery can decrease the battery voltage under high-temperature conditions and cannot be recharged after being exposed to high-temperature conditions.

Lithium ion secondary battery

Growing community of inventors

Osaka, Japan

Te Hyon Cho