The electric motor of a power shovel is powered using power stored in a power storage module. The power storage module includes a plurality of layered cell units forming a layered structure. Each of the cell units has a power storage cell containing a pair of electrode tabs, and a frame for supporting the power storage cell. Each of the frames has a screw clamp section formed on a surface facing the side of the layered structure. The electrode tabs of the power storage cells are screwed and clamped to the screw clamp sections, causing the plurality of power storage cells to be electrically connected.
