Dual-function equalization system of lithium battery

The bifunctional equalization system comprises a plurality of battery packs connected in series, a plurality of bidirectional direct current-direct current converters, a plurality of resistor structures and a control system, the battery pack comprises a plurality of battery cells connected in series, and the bidirectional DC-DC converter is arranged corresponding to the battery cells; the bidirectional direct current-direct current converter comprises a port X connected with the positive electrode and the negative electrode of the battery cell, and a port Y used for connecting all the bidirectional direct current-direct current converters in parallel; the bidirectional DC-DC converter is in communication connection with the control system; the resistor structure corresponds to the battery pack, is electrically connected with positive and negative electrodes of the battery pack, and is in communication connection with the control system; the control system controls charging and discharging of the battery cells