A system for the storage of electric energy for a vehicle with electric propulsion, which presents a longitudinal direction, which is parallel to the direction of the rectilinear motion, and a transverse direction, which is perpendicular to the longitudinal direction; the storage system is provided with a pack of chemical batteries, which are connected to each other in series and in parallel and comprise respective electrochemical cells; each chemical battery has a cylindrical shape having a central symmetry axis; and a support matrix made of plastic material is provided, inside which the chemical batteries are embedded so that the chemical batteries are completely covered by the support matrix itself.