To prevent an abnormal temperature rise of a lithium ion secondary battery when broken.
This secondary battery consists of a positive electrode of composite metal oxide which can occlude and discharge lithium ion, a negative electrode of carbon material which can occlude and discharge lithium ion, a separator and nonaqueous electrolyte. In this case, it is structured so that an average value of the primary particle diameter of composite metal active substance of the positive electrode calculated from a photo taken by a scanning electron microscope is 1.5m, and the stocking strength of the separator is 100-800g. Thereby, a temperature rise of the battery can be presented when broken, and a lithium secondary battery with excellent safety can be obtained.
MURAI SUKEYUKI
YONEHARA TOMOKICHI
TAKAHASHI YUI
Next Patent: NONAQUEOUS ELECTROLYTE SECONDARY BATTERY