Battery Management Apparatus and Operating Method Thereof

A battery management apparatus includes an information obtaining unit configured to obtain an open circuit voltage of a plurality of battery cells and a controller configured to calculate a first voltage of each of the plurality of battery cells, which is related to a change in open circuit voltage of the plurality of battery cells, for a preset time, calculate a second voltage that is an average of the first voltage of each of the plurality of battery cells, calculate a deviation based on a first voltage and a second voltage of each of the plurality of battery cells, and diagnose the plurality of battery cells based on a ratio of the first voltage and the second voltage of each of the plurality of battery cells and the deviation.