Cylindrical power lithium ion battery

A disclosed cylindrical power lithium ion battery comprises a roll core assembly, an electrolyte, a cylindrical shell and a cap terminal, the roll core assembly comprises a positive pole piece, a negative pole piece and a diaphragm spaced between the positive pole piece and the negative pole piece, an active substance of the positive pole piece contains a lithium transition metal oxide containing a phosphorus element, and an active substance of the negative pole piece contains a lithium transition metal oxide containing a phosphorus element; the lithium ion battery at least meets one of the following relational expressions: (1) the porosity P of the positive pole piece and the thickness H of the positive pole piece meet the relational expression: P/Hgt; 1.5, wherein the unit of H is mm; and (2) the thickness H of the positive pole piece and the inner diameter M'of the cylindrical shell meet the relational expression that 1000 * H/M 'is more than 1.25 and less than 7.6. By optimizing the material structure com