Patent ID: 7704640

Claim:
A non-aqueous electrolyte secondary cell comprising: a positive electrode having a positive electrode active material; a negative electrode having a negative electrode active material; and a non-aqueous, wherein the positive electrode active material has a lithium-cobalt compound oxide having added therein at least zirconium; the non-aqueous electrolyte has a non-aqueous solvent, LiBF 4 and electrolytic salt being at least one selected from the group consisting of LiPF 6 , LiN(C 2 F 5 SO 2 ) 2 , LiN(CF 3 SO 2 ) 2 , and LiClO 4 , and an unsaturated cyclic carbonate which is a vinylene carbonate; the content of the LiBF 4 is from 0.05 to 1.0 mass % of a total mass of the non-aqueous electrolyte; the content of the vinylene carbonate is from 1.0 to 4.0 mass % of a total mass of the non-aqueous electrolyte; and a true density ratio of the positive electrode is 0.72 or greater, the true density ratio being represented by formula 1 shown below: True density ratio=active material apparent density of electrode active material layer÷true density of active material. (Formula 1)