Battery management system

A battery management system which manages a battery pack including at least two battery assemblies connected in a sequential order, the battery management system comprising:

• at least two battery management devices each having a first terminal outputting a variable voltage and a second terminal outputting a constant voltage, and provided for each battery assembly;
• at least two slave switch units connected to each other in sequential order, and provided for each battery management device and connected between the first terminal and the second terminal, the slave switch units selectively turning on or turning off based on the variable voltage outputted from the first terminal;
• and
• an information transfer unit to transmit information from the battery management device to an external device,
• wherein among the slave switch units, when a slave switch unit provided in a battery management device intended to transmit information to the external device turns on, the slave switch units turn on in a sequential order toward a last slave switch unit provided the last among the slave switch units, to form an information transfer path to allow the information transfer unit to transmit the information to the external device.