| abstract |
The present invention provides a secondary battery. The secondary battery comprises a positive electrode piece, a negative electrode piece, an electrolyte, and an isolating film; the positive electrode piece comprises a positive current collector and a positive diaphragm provided on at least one surface of the positive current collector and comprising an positive active material; and the negative electrode piece comprises a negative current collector and a negative diaphragm provided on at least one surface of the negative current collector and comprising a negative active material. The secondary battery also meets: 0.1≤(D50negative electrode×Mnegative electrode)/[(D50positive electrode+4)×(Mnegative electrode+4)]≤1.5. The secondary battery having the advantages of long cycle life, high energy density, and quick charging and discharging capacity, provided by the present invention, is obtained by reasonably matching a relationship between particle sizes of the positive and negative active materials and capacities of the positive and negative diaphragms. |