BATTERY SYSTEM AND METHOD FOR MANAGING BATTERY SYSTEM

A battery system includes: at least two battery packs; a plurality of first relays, each first relay being connected to a respective one of the at least two battery packs; and an auxiliary battery, a first battery pack among the at least two battery packs with a highest voltage is discharged to the auxiliary battery through the first relay connected to the first battery pack so that a voltage of the first battery pack approaches a voltage of another battery pack, a second battery pack with a lowest voltage is charged by the auxiliary battery through the first relay connected to the second battery pack so that the voltage of the second battery pack may approach the voltage of the another battery pack, and the at least two battery packs are connected in parallel.