NON-AQUEOUS ELECTROLYTE SECONDARY BATTERY

摘要

PROBLEM TO BE SOLVED: To solve a problem in a lithium ion secondary battery that its thermal runaway may be caused in an abnormal condition and that, especially when thermal decomposition of a positive electrode active material is caused by the increase in the battery temperature, its thermal runaway is accelerated by oxygen emission accompanying the thermal decomposition. SOLUTION: Safety can be ensured even in an abnormal condition by selecting the positive electrode active material with an exothermic peak of 270 deg.C or above, which is attributed to the thermal decomposition, based on the DSC measurement.