BATTERY PACK, BATTERY SYSTEM AND PRECHARGE METHOD

A battery pack includes a battery cell, a main relay provided on a charging and discharging path of the battery cell, a precharge relay, a precharge resistor, the precharge relay and the precharge resistor being connected in parallel to the main relay on the charging and discharging path, a connector connected to a load including a capacitor; a communication part receiving a capacitance of the capacitor from the load through the connector, when the load is connected to the connector, and a controller obtaining the capacitance from the communication part, calculating a duty ratio corresponding to the capacitance, and precharging the capacitor by controlling an operation state of the precharge relay according to the calculated duty ratio.