A battery pack may include: a battery configured to include a plurality of cells; a cell balancing circuit configured to include a discharge circuit for each of the cells; a controller configured to output a first complete discharge command signal based on a control signal inputted from the outside; a mechanical switch configured to output a second complete discharge signal by mechanical manipulation; and a cell balancing controller configured to control the cell balancing circuit such that complete discharge of each cell is performed through the discharge circuits when the first complete discharge signal and the second complete discharge signal are received.