Patent ID: 6939644

Claim:
A lithium secondary cell comprising a lithium secondary cell element using, as a positive electrode active material, a lithium-nickel compound oxide containing lithium and nickel, accommodated in a casing, wherein the specific surface area of the lithium-nickel compound oxide is from 0.1 to 10 m 2 /g, and a surface area capacity ratio S/C, i.e. a ratio of a cell surface area S (cm 2 ) to a cell capacity C (mAh), is from 0.05 to 5 wherein S is defined as the outside surface area of the casing accommodating the cell element and C is defined as the maximum discharge capacity obtainable when the cell is discharged from a fully charged state of 4.2 V to 3.0 V at such a current that 3.0 V will be reached at 10 hours.