METHOD OF BATTERY BALANCING AND BATTERY SYSTEM PROVIDING THE SAME

A method of voltage balancing among a plurality of battery modules connected in series and supplying power to an external device, and a battery system providing the same, and the battery system of the present invention includes: a battery pack including a plurality of battery modules; a switching circuit connecting the plurality of battery modules in series or in parallel; and a battery management system (BMS) controlling the switching circuit so as to connect the plurality of battery modules in series in a discharge mode to supply power from the battery pack to an external device, a charge mode to charge the battery pack by receiving the power from the external device, and a module balancing mode to charge the plurality of battery modules with the power applied from the external device until a voltage difference is a predetermined reference value or less.