SEPARATOR FOR LITHIUM ION SECONDARY BATTERY, LITHIUM ION SECONDARY BATTERY USING THE SAME, AND SECONDARY BATTERY SYSTEM USING LITHIUM ION SECONDARY BATTERY

摘要

PROBLEM TO BE SOLVED: To provide a separator for a lithium ion secondary battery in which three items of capacity, safety and heat resistance can be balanced with higher level when compared with a compact electronic apparatus so as to apply a lithium ion secondary battery to a large electric apparatus, and to provide a lithium ion secondary battery and a secondary battery system in which the three items of capacity, safety and heat resistance are balanced with higher level.SOLUTION: A separator for a lithium ion secondary battery according to the present invention is a separator partitioning the positive electrode and the negative electrode in a lithium ion secondary battery. The separator consists of a porous body having a large number of pores, and an overcharge inhibitor having a predetermined functional group is carried on the surface of the porous body. When the lithium ion secondary battery reaches the temperature of an overcharge region, the predetermined functional group generates inert gas which closes the pores.