A method for implementing a system for the storage of electric energy for a vehicle with electric propulsion; the storage system comprises: a pack of chemical batteries, which are connected to each other in series and/or in parallel, comprise respective electrochemical cells and each of which has a cylindrical shape having a central symmetry axis; and a support matrix made of a plastic material and having a parallelepiped shape, inside of which the chemical batteries are arranged; the method comprises the steps of: implementing the support matrix separately and independently of the chemical batteries so as to form an empty support matrix having a plurality of through holes, each of which is adapted to receive and contain a corresponding chemical battery; axially inserting each chemical battery into a corresponding through hole of the support matrix so that only a central portion of the chemical battery is engaged by the support matrix, while the two end portions of each chemical battery protrude from the support matrix; and implementing the electric connections of the chemical batteries after having inserted the chemical batteries into the through holes of the support matrix; the method is characterized in that it comprises the further steps of: housing the pack of chemical batteries embedded in the support matrix in a container; and adjusting the mechanical strength of the container and of the support matrix so that the mechanical strength of the container and of the support matrix is lower than the mechanical strength of the single chemical batteries and, in case of crash, the container and the support matrix collapse by getting deformed while the single chemical batteries remain entire and are displaced with respect to the container and to the support matrix. a pack of chemical batteries, which are connected to each other in series and/or in parallel, comprise respective electrochemical cells and each of which has a cylindrical shape having a central symmetry axis; and a support matrix made of a plastic material and having a parallelepiped shape, inside of which the chemical batteries are arranged; the method comprises the steps of: implementing the support matrix separately and independently of the chemical batteries so as to form an empty support matrix having a plurality of through holes, each of which is adapted to receive and contain a corresponding chemical battery; axially inserting each chemical battery into a corresponding through hole of the support matrix so that only a central portion of the chemical battery is engaged by the support matrix, while the two end portions of each chemical battery protrude from the support matrix; and implementing the electric connections of the chemical batteries after having inserted the chemical batteries into the through holes of the support matrix; implementing the support matrix separately and independently of the chemical batteries so as to form an empty support matrix having a plurality of through holes, each of which is adapted to receive and contain a corresponding chemical battery; axially inserting each chemical battery into a corresponding through hole of the support matrix so that only a central portion of the chemical battery is engaged by the support matrix, while the two end portions of each chemical battery protrude from the support matrix; and implementing the electric connections of the chemical batteries after having inserted the chemical batteries into the through holes of the support matrix; the method is characterized in that it comprises the further steps of: housing the pack of chemical batteries embedded in the support matrix in a container; and adjusting the mechanical strength of the container and of the support matrix so that the mechanical strength of the container and of the support matrix is lower than the mechanical strength of the single chemical batteries and, in case of crash, the container and the support matrix collapse by getting deformed while the single chemical batteries remain entire and are displaced with respect to the container and to the support matrix. housing the pack of chemical batteries embedded in the support matrix in a container; and adjusting the mechanical strength of the container and of the support matrix so that the mechanical strength of the container and of the support matrix is lower than the mechanical strength of the single chemical batteries and, in case of crash, the container and the support matrix collapse by getting deformed while the single chemical batteries remain entire and are displaced with respect to the container and to the support matrix.