Lithium-ion secondary battery, battery device and power-consuming device

Abstract

A lithium-ion secondary battery, characterized in that it comprises: a positive electrode plate, a negative electrode plate and an electrolyte, wherein the positive electrode plate comprises a positive electrode current collector and a positive electrode film layer arranged on at least one side of the positive electrode current collector, wherein the positive electrode film layer comprises a positive electrode active material, wherein the positive electrode active material comprises lithium transition metal phosphate particles, wherein the lithium transition metal phosphate particles comprise a lithium transition metal phosphate matrix and a coating layer located on at least a part of the surface of the lithium transition metal phosphate matrix, wherein the coating layer contains an element carbon;wherein, in the cross-section of the positive electrode film layer along the thickness direction of the electrode plate, the fraction of particles I with a particle size of less than 300 nm, based on the total number of lithium transition metal phosphate particles, is 60% to 70%; wherein the RA50 value of the roughness of the lithium transition metal phosphate particles is greater than or equal to 0.86, where the RA50 value of the roughness of the lithium transition metal phosphate particles denotes the roughness of the lithium transition metal phosphate particles that is achieved at 50% cumulative area distribution of the lithium transition metal phosphate particles in the cumulative area distribution curve of the roughness of the lithium transition metal phosphate particles.