Disclosed herein are an electric energy storage apparatus, a voltage equalization module thereof, and a voltage equalization method. There is provided an electric energy storage apparatus, including: a plurality of electric energy storage cells connected in series; voltage sensing units sensing voltage charged in each of the electric energy storage cells, respectively; first bypass discharge units connected to each of the electric energy storage cells in parallel, respectively, and bypassing and discharging electric energy charged; second bypass discharge units additionally connected to each of the electric energy storage cells in parallel, respectively, and bypassing and additionally discharging electric energy; and a control unit receiving voltage information from the voltage sensing units, determining whether controlling or not and controlling operations of each of the first and second bypass discharge units so as to equalize charged voltage values of the electric energy storage cells.