BATTERY SYSTEM

A battery system may include at least one battery module including a battery cell configuration unit and a slave battery management system (BMS) managing the battery cell configuration unit includes a communication unit of the slave BMS, a capacitor connected between the communication unit and a first ground, a first inductor and a second inductor connected in series between a contact between the first ground and the capacitor and a second ground, and a control unit transmitting an AC signal having a predetermined frequency to the communication unit in an antenna mode in which the slave BMS communicates with an outside. In addition, the second inductor may be configured of a wire so that a first antenna impedance determined by the first inductor matches a second antenna impedance of a master BMS that is a communication target.