While discussions about electric vehicles often spotlight screen sizes, software efficiency, and battery life, the real engineering advancements occur within the vehicle's chassis. Mercedes-Benz aims to showcase its mechanical prowess by initiating large-scale production of a distinctive electric motor at its historic Berlin-Marienfelde facility, established in 1902 and the oldest plant in its history. Rather than shutting the factory down, management has transformed it into a high-tech center for premium electric vehicles and advanced propulsion technologies.
Most electric vehicles currently utilize conventional radial flux motors, where magnetic forces extend outward like bicycle spokes. In contrast, Mercedes-Benz is making a substantial investment in axial flux technology. In this design, electromagnetic forces flow parallel to the rotating axle, allowing internal components to be arranged in a flat, disc-like configuration.
The image above illustrates how two magnetic rotors sandwich a central stator, optimizing space and boosting power output significantly.
The new motor is officially debuting in the high-performance Mercedes-AMG GT 4-door Coupe. Thanks to the axial flux architecture's slim profile, the front-axle motor measures under 9 cm in width, while the two rear-wheel motors are even more compact, each about 8 cm wide. These efficient powerplants are integrated into a compact High Performance Electric Drive Unit, which combines the motors with a small planetary gearbox, optimizing space.
Despite their compact size, these motors offer impressive performance. The front-axle motor reaches speeds exceeding 15,000 revolutions per minute. Together, they propel the all-electric Mercedes-AMG GT 4-door Coupe from a standstill to 62 mph in just 2.1 seconds. Those opting for the additional Driver's Package can enjoy a remarkable top speed of 186 mph.
The early prototypes for this innovative technology were developed by the British firm YASA, which Mercedes-Benz acquired in 2021 due to the motor's potential. Before mass production began, a technology demonstrator, the CONCEPT AMG GT XX, underwent rigorous testing, completing an endurance challenge at the Nardo track in Italy, covering over 24,900 miles and setting 25 long-distance speed records.
Transitioning from prototype to mass production is a significant challenge in the automotive industry. To facilitate this, the Berlin factory allocated 30,000 square meters of space across three extensive halls and seven production lines. The assembly process involves 98 distinct steps, with 65 designed specifically for Mercedes-Berlin, while 35 are entirely new to global manufacturing, resulting in over 30 new patent applications.
The unique design of the motor presents considerable manufacturing hurdles. Workers use flat, rectangular copper wire to form internal coils rather than conventional round wire. This square shape allows for more copper to fit within the limited space but complicates the bending of thick wire around sharp corners without damaging the insulation. Automated lasers are employed to weld the delicate wire ends in a confined housing, with precise heat application to prevent melting adjacent plastic components.
Another challenge lies in laser transmission welding of plastic drivetrain parts, which requires geometric precision to avoid damaging surrounding components. To ensure reliable production, Mercedes-Benz utilizes optical AI software to monitor weld joints in real time, identifying the precise positions of parts and creating virtual safety zones around delicate areas while guiding the laser path. This process creates reliable seals that withstand high oil pressure and significant physical stress.
The most dramatic moment in the assembly line occurs during a step referred to as the "wedding," where automated arms precisely lower the central stator between the two magnetic rotor discs. The permanent magnets generate a tremendous pull, approximately 1,984 lb of force. The robotic system must maintain the stator's exact position with an extraordinary tolerance of less than 0.004 inches, with a computer program actively monitoring alignment and making adjustments in real-time during the final seconds of the assembly.
The advanced assembly lines operate adjacent to the Mercedes-Benz Digital Factory Campus, where the company has been testing new manufacturing software since 2022 using its MO360 digital network. The launch of the axial flux motor line coincides with a significant milestone for the brand, marking 140 years since Carl Benz patented his original vehicle in 1886. To commemorate this anniversary, the automaker is showcasing three S-Class sedans on a promotional tour visiting 140 locations worldwide until October.
Corporate leaders will spend the year honoring historical gasoline vehicles and promoting electric models like the CLA and GLC. However, the company's future rests on these advanced electric motors. Competing globally necessitates high production volumes and consistent quality. By investing in 35 innovative assembly processes, Mercedes-Benz aims to position its ultra-thin motors as a permanent advantage over international competitors.
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