Secondary battery

Abstract

A secondary battery includes a positive electrode, a negative electrode, a separator, and an electrolytic solution. The separator is disposed between the positive electrode and the negative electrode. The positive electrode includes primary particles as a positive electrode active material. The separator includes a porous layer and a covering layer. The covering layer is disposed between the porous layer and the positive electrode. The covering layer includes insulating particles. The insulating particles each have a major axis and a minor axis. An average particle size of the primary particles is greater than or equal to 100 nm and less than or equal to 2120 nm. A ratio of an average length of the respective minor axes of the insulating particles to the average particle size is greater than or equal to 0.22 and less than or equal to 1.00.

Dependencies are inferred from the claim text.