1. In an electric drive system comprising:an electric motor having a stator with a current-feed system and an output shaft defining a rotation axis;
a power supply axially adjacent the electric motor and around the rotation axis of the electric motor circumferentially, and
a plurality of energy-storage cells in the power supply, the improvement wherein:
the power supply is cylindrical and formed by a plurality of axially adjacent disks each in turn subdivided angularly into a plurality of segments each formed with a plurality of axially extending cylindrical seats each holding a respective one of the energy-storage cells, each seat being aligned axially with the seats of adjacent disks;
each segment is aligned axially with a respective one of the segments of adjacent disks and forms therewith a respective energy-storage module extending a full axial length of the power supply, independent of the other energy-storage modules, and capable of powering the motor;
a control board between opposing axial end faces of the electric motor and of the power supply; and
respective power electronics on the control board each connected between a respective one of the energy storage modules and the current-feed system of the electric motor.