CYLINDRICAL SECONDARY BATTERY COMPRISING IMPROVED CURRENT COLLECTOR PLATE, BATTERY PACK AND VEHICLE INCLUDING THE SAME

A cylindrical secondary battery according to the present disclosure includes a jelly-roll type electrode assembly having a structure in which a positive electrode plate and a negative electrode plate having a sheet shape and a separator interposed therebetween are wound in one direction, the positive electrode plate including a positive electrode uncoated portion exposed to the outside of the separator at a long side end, the negative electrode plate including a negative electrode uncoated portion exposed to the outside of the separator at a long side end; a positive electrode current collector plate coupled to the positive electrode uncoated portion by a positive electrode welding portion; and a negative electrode current collector plate coupled to the negative electrode uncoated portion by a negative electrode welding portion, wherein a coupling area (S 1) between the positive electrode uncoated portion and the positive electrode current collector plate is smaller than a coupling area (S2) between the negative electrode uncoated portion and the negative electrode current collector plate. According to the present disclosure, by improving the positive electrode current collector plate and the negative electrode current collector plate, it is possible to secure the kinetic balance between the positive electrode and the negative electrode, improve the energy density and strengthen the coupling force between components.