SECONDARY BATTERY AND ELECTRICAL DEVICE

A secondary battery includes a positive electrode plate and a negative electrode plate; the positive electrode plate includes a positive electrode current collector and a positive electrode film layer arranged on at least one of the surfaces of the positive electrode current collector, the positive electrode film layer includes a positive electrode active material, the negative electrode plate includes a negative current collector and a negative electrode film layer arranged on at least one of the surfaces of the negative current collector, the negative electrode film layer includes a negative electrode active material; the secondary battery satisfies 0.15≤(1000*(B/A))/((T*D)*(n/4))≤0.50, in which B/A represents the capacity-excess coefficient of the negative electrode of the secondary battery, dimensionless, T represents the thickness of the negative electrode film layer, in μm, and D represents the volume average particle size Dv50 of the negative electrode active material, in μm.