| abstract |
A lithium ion secondary battery with improved safety against both internal short-circuiting and overcharge is provided. This lithium ion secondary battery includes a positive electrode comprising a composite lithium oxide, a negative electrode, and a non-aqueous electrolyte. At least one of the positive electrode and the negative electrode has a porous film, comprising an inorganic oxide filler and a binder, on the surface facing the other electrode, and the electrode surface having the porous film partially has a protruded part. This protruded part may be a protruded part formed on the porous film itself or a protruded part formed on an electrode mixture layer. Further, a separator can also be incorporated therein. Instead of the above-mentioned porous film, the separator can be provided with a porous film. |