Mercedes-Benz starts series production of an axial flux motor in Berlin

Mercedes-Benz has begun large-scale series production of an electric axial flux motor at its Berlin-Marienfelde plant, the company announced on 9 June. Founded in 1902, Marienfelde is the company's oldest manufacturing site and has hosted the Mercedes-Benz Digital Factory Campus since 2022. It is now positioned as a centre of excellence for high-performance electric motors.

98 process steps, 35 of them new worldwide

Building the motor takes 98 process steps. Sixty-five are used for the first time at Mercedes-Benz and 35 are new worldwide, according to the company, and the technologies developed for the line have produced more than 30 patent applications. Production covers around 30,000 square metres across three halls and seven production lines, combining highly automated processes, laser technology, intelligent control systems and AI-based quality control.

Copper, laser and magnet forces

The stator uses rectangular copper wire instead of round wire, fitting more copper into the same space and raising power density; the wire must be bent at high speed into tight radii without creases or damaged insulation. Each coil end is joined to its interconnection wire by a precisely controlled laser weld in a very confined space, keeping heat away from nearby plastic parts. Final assembly, known internally as the “wedding”, places the stator between two magnet-carrying rotor discs. Magnetic forces of up to 9 kilonewtons, roughly 900 kilograms, act on the components, while the stator has to stay within the magnetic centre plane to a tolerance below 0.1 millimetres; a control algorithm corrects its position in the final half second.

Why axial flux matters

In an axial flux motor the electromagnetic flux runs parallel to the axis of rotation and the components are arranged as discs: two rotors sandwich the stator. The layout is compact, gives high power and torque density, and frees up space in the drivetrain. In the new Mercedes-AMG GT 4-Door Coupe the front motor is just under nine centimetres wide and each of the two rear motors measures about eight centimetres. All three sit inside High Performance Electric Drive Units, combined with a compact planetary gearbox in one housing; the front motor revs past 15,000 rpm. The British specialist YASA developed the prototype on which the motor is based and has been a wholly owned Mercedes-Benz subsidiary since 2021.

Record run and reaction

The all-electric GT 4-Door Coupe accelerates from 0 to 100 km/h in as little as 2.1 seconds and reaches 300 km/h with the Driver's Package. In an earlier demonstration the CONCEPT AMG GT XX covered more than 40,000 kilometres in seven days and 13 hours at Nardò and set 25 long-distance records. Michael Schiebe, the Mercedes-Benz board member responsible for production, quality and supply chain management, called the start of production a signal of technological leadership and of the transformation of the German automotive industry. Berlin's senator for mobility, Ute Bonde, said the city needs success stories of this kind because they secure jobs.