LITHIUM ION SECONDARY BATTERY AND METHOD FOR MANUFACTURING SAME

摘要

Disclosed is a lithium ion secondary battery which is improved in safety related to both internal short circuit and overcharge. This lithium ion secondary battery comprises a positive electrode composed of a lithium complex oxide, a negative electrode and a nonaqueous electrolyte solution. At least one of the positive electrode and negative electrode has a porous membrane containing an inorganic oxide filler and a binder on a surface which is opposite to the other electrode, and this electrode surface is partially provided with projected portions. In this connection, the porous membrane itself can be formed to have projected portions or the electrode mix layer is provided with projected portions, thereby forming corresponding projected portions in the porous membrane. The lithium ion secondary battery may further comprises a separator, and a porous membrane can be alternatively arranged on the separator.