BATTERY SYSTEM INCLUDING POWER SUPPLY UNIT AND OPERATING METHOD THEREOF

A battery system according to an embodiment of the present invention may comprise: a battery; a circuit breaker disposed on a charging/discharging line of the battery; and a battery management device for managing the battery and controlling the operation of the circuit breaker. Here, the battery management device may comprise: a control unit; a power supply unit which receives power from the battery through a first power supply line and supplies power to the control unit; and a power maintenance unit which receives power from the battery through a second power supply line and supplies temporary power to the power supply unit in a state in which the circuit breaker is open.