The age of the electric motor began with Hans Christian Ørsted, who realised in 1820 that a magnetic field forms around a conductor through which current flows. A few years later, a famous race triggered a brief hype about battery electric vehicles. However, it is only the progress that Formula E is currently making along the entire drive train that is helping electromobility to achieve a global breakthrough.

The age of the electric motor began with Hans Christian Ørsted, who realised in 1820 that a magnetic field forms around a conductor through which current flows. A few years later, a famous race triggered a brief hype about battery electric vehicles. However, it is only the progress that Formula E is currently making along the entire drive train that is helping electromobility to achieve a global breakthrough.

A modern Formula E racing car produces 250 kW at a supply voltage of 900 V. Until recently, 700 V was still common. Series electric vehicles with permanent magnet three-phase synchronous motors for individual road traffic, on the other hand, are operated at 400 V. But it is not only the operating voltage that has increased over time, the efficiency of the entire drive train has also been improved. For example, a battery-electric racing car from the current Formula E series can only run for about one hour with an energy quantity of 52 kWh, but at much higher speeds.



So a lot has happened since the two Dutchmen Sibrandus Stratingh and Christopher Becker developed an electric motor to power a small model car in 1835 and the first patent for an electric motor in 1837 to Thomas Davenport. Over the past decades, engineers have made considerable improvements, particularly in the rotor, stator and housing, the three essential components of an electric motor.

The state of the art currently includes the Racing eDrive01 of the BMW iFE.18. It originates from the pre-development for series drives and is produced in the same prototype construction as the next generation of series drives of the BMW i. It consists of the electric machine, the cooling system and the inverter. In designing all components, the developers have paid attention to maximum efficiency, the highest possible power density and the most compact lightweight construction possible. Among other things, fiber composite bandages are used on the rotor to reduce weight and to strengthen it.




The successes are considerable. Compared to the drive system of the BMW i3, for example, the weight has been reduced by almost 50%, while the size is around 66% smaller. In terms of performance, the racing engine is 100 % more powerful, the energy density has been increased by 300 %, the torque density by 100 %. These advances clearly show that electric cars can now easily compete with petrol and diesel vehicles in terms of performance. In terms of efficiency, they are even clearly superior to them. The energy consumption of conventional electric vehicles averages about 14 kWh/100 km (WLTP) over all models currently available on the market.

The engineers of the Volabo start-up company want to show that the efficiency of electric motors can be increased even further. The spin-off from the University of the German Armed Forces in Munich recently succeeded in developing a 48 V electric motor for electric mobility applications, which now uses a solid stator cage with aluminium rods instead of copper coils for the stator in the electric motor. This drive is safer, more reliable and above all more efficient than previous electric motors. A further advantage of the Intelligent Stator Cage Drive (ISCAD) is that production costs are about 40% lower. In a conventional electric motor, the copper coils have to be wound in a complex process.