A battery system for a vehicle may include: a charging apparatus configured to receive an alternating current power from the outside thereof in a wired/wireless manner; an on-board charger (OBC) configured to convert the alternating current power of the charging apparatus into a direct current power; a micro-control unit (MCU) configured to boost an output voltage of the OBC by use of a boost converter configured by a motor and an inverter; and a battery connected to the MCU and configured to be charged with the boosted output voltage.