Abstract: The present invention provides a BMS having a master BMS and at least one slave BMS that receive power from an electric vehicle, wherein each of the master BMS and the slave BMS has first and second ground terminals, the first ground terminals of the master BMS and the slave BMS are connected to a ground terminal of the electric vehicle, the second ground terminal of the master BMS is connected to the first ground terminal of the master BMS, and the second ground terminal of the slave BMS is connected to the second ground terminal of the master BMS.