Disclosed are a communication method between a master controller and slave controllers, a slave controller for the communication method, and a battery management system using the communication method and the slave controller, in which the master controller receives safety information about battery cells through a plurality of channels even when each of a plurality of slave controllers includes only one micro controller unit, thereby minimizing the increase in the cost and enhancing the safety of the battery management system. The communication method includes performing bidirectional communication between a master controller and first to Nth (where N is an integer equal to or more than two) slave controllers through a first communication channel, and receiving, by the master controller, an indication signal through a second communication signal via the first to Nth slave controllers.