Battery Management System and Battery Management Method Thereof

A battery management system comprising:

• a state information calculation unit that calculates state information of at least one of a plurality of battery cells;
• and
• a cell selection unit that selects at least one battery cell of a high-risk group using the state information,
• wherein the at least one battery cell of the high-risk group includes a battery cell having a terminal voltage that is out of an operating voltage during a charge or a discharge, and
• the cell selection unit calculates a maximum voltage change amount of the plurality of battery cells, calculates a voltage threshold value serving as a reference for selecting the at least one battery cell of the high-risk group by using the maximum voltage change amount, and selects the at least one battery cell of the high-risk group based on the voltage threshold value.