Mercedes-Benz Kicks Off Axial Flux Motor Production: An Engineering

Mercedes-Benz has announced the commencement of large-scale production for its electric axial flux motors at the historic Berlin-Marienfelde plant. This move marks a significant leap in electric vehicle (EV) powertrain technology, bringing a high-performance, compact motor design from vision to industrial reality. For us developers, this isn't just about a new car part; it's a testament to overcoming immense engineering and manufacturing challenges, pushing the boundaries of precision, automation, and AI integration in a complex physical domain.

The Allure of Axial Flux

Conventionally, most electric motors, including those in current EVs, are radial flux designs. In these motors, the electromagnetic flux flows perpendicular to the axis of rotation. The newer axial flux design, however, reorients this. Here, the electromagnetic flux runs parallel to the rotational axis. The core components – two rotors sandwiching a stator – are arranged disc-like, leading to a notably compact and powerful package.

This fundamental difference yields several advantages:

Compactness: Axial flux motors are significantly flatter, offering greater freedom in vehicle packaging. For instance, the motors in the new Mercedes-AMG GT 4-door Coupé measure just nine centimeters wide for the front axle unit and eight centimeters each for the two rear axle units.
High Power and Torque Density: Their design allows for more active material (like copper) within a smaller volume, translating to higher power and torque output for their size. The front axle motor, for example, achieves speeds exceeding 15,000 revolutions per minute.
Performance Potential: Integrated into High Performance Electric Drive Units (HP.EDU) with a compact planetary gear, these three motors enable the AMG GT 4-door Coupé to accelerate from 0 to 100 km/h in as little as 2.1 seconds, reaching a top speed of 300 km/h with the optional Driver's Package.

The foundational prototype for this motor was developed by YASA, a British electric motor specialist, acquired by Mercedes-Benz in 2021. Since then, Mercedes-Benz has rigorously evolved the technology and its production process for high-volume automotive application.

Industrializing Complexity: A Manufacturing Odyssey

Bringing the axial flux motor to mass production was no small feat. The manufacturing process involves 98 distinct steps, with 65 of them being entirely new to Mercedes-Benz and a remarkable 35 processes being globally unprecedented. This innovation led to over 30 patent applications, showcasing the depth of R&D invested.

Mercedes-Benz has dedicated approximately 30,000 square meters across three halls and seven production lines at the Berlin-Marienfelde plant. This high-tech environment seamlessly blends advanced automation, laser technology, intelligent control systems, and AI-powered quality assurance with the specialized expertise of its workforce. Let's look at some key innovations:

Precision Copper Coil Production: To achieve the high power density, the stator utilizes rectangular copper wire instead of traditional round wire. This allows more copper to be packed into the same space. The challenge lies in bending this rectangular wire into tight radii at high speeds without deforming its cross-section, damaging insulation, or creating wrinkles. Mercedes-Benz, in collaboration with partners, developed a specialized process that combines extreme precision with industrial cycle times.
Laser Welding of Coil Packages: Connecting the coil ends within the stator is another intricate task, requiring precise connections in a very confined space without thermally damaging adjacent plastic structures. The solution involves high-precision laser welding of the copper wires, ensuring minimal energy input at the weld joint and a very short process time.
AI-Enhanced Polymer Welding: The powertrain includes plastic components joined by simultaneous laser transmission welding. This demands exceptional geometric accuracy and minimal invasive energy to prevent damage to surrounding areas. Here, AI-supported optical real-time quality control plays a crucial role, documenting the connection instantly to bolster process reliability. For component conditioning, AI-driven image processing identifies the exact position of a part, establishes virtual protective zones over sensitive areas, and ensures the laser only processes the intended surfaces. The result is robust, oil-pressure-tight, and mechanically resilient connections.
The "Marriage" – High-Precision Final Assembly: Internally dubbed the "Hochzeit" (marriage), this stage involves precisely positioning and permanently joining the stator between the two magnet-equipped rotor discs. Magnetic forces of up to 9 kilonewtons (equivalent to approximately 900 kilograms) act on the components, yet the stator must remain within a tolerance of less than 0.1 millimeters in the magnetic center plane. An innovative control algorithm corrects the stator's position with high-frequency control pulses in the final 0.5 seconds of the process, demonstrating how intelligent control, sensitive sensors, and exact process management are paramount, not just raw force.

Digital Factory Campus as an Innovation Hub

This manufacturing breakthrough is deeply intertwined with the strategic evolution of the Berlin-Marienfelde site. Since 2022, the plant has hosted the Mercedes-Benz Digital Factory Campus, a central hub for digitalizing production across the global Mercedes-Benz network. It serves as a real-world production environment for developing and testing digital applications based on the MO360 production ecosystem. The industrialization of the axial flux motor thus marries high-performance electric drives with advanced digital production and intelligent automation, positioning Berlin-Marienfelde as a key player in scaling new technologies with quality assurance.

Practical Takeaways for Developers

For those of us working in software, the story of the axial flux motor's mass production offers compelling insights:

Hardware-Software Synergy: It highlights how cutting-edge hardware development is inseparable from sophisticated software – intelligent control algorithms, AI for quality control, and digital factory ecosystems are foundational to manufacturing previously impossible designs.
Precision Engineering at Scale: The emphasis on sub-millimeter tolerances, laser technology, and complex automation demonstrates the relentless pursuit of precision in modern manufacturing, a domain where even seemingly minor software bugs could have catastrophic physical consequences.
The Future of Automotive: As EVs become more prevalent, the demand for compact, powerful, and efficient powertrains will only grow. Axial flux motors represent a significant direction, signaling a future where hardware innovations are unlocked through parallel advancements in manufacturing technology and digital intelligence.

FAQ

Q: What is the primary advantage of axial flux motors compared to conventional radial flux motors, specifically in the context of EVs?

A: The main advantage for EVs is their compact design and higher power/torque density. This allows for more flexible vehicle packaging (e.g., flatter motors), better integration into electric drive units, and superior performance metrics like rapid acceleration, all within a smaller physical footprint compared to radial flux motors of equivalent power.

Q: How does AI contribute to the manufacturing process of these axial flux motors?

A: AI plays a crucial role in enhancing precision and process reliability. Specifically, AI-supported optical real-time quality control is used during polymer welding to ensure the integrity of connections. AI-driven image processing identifies exact component locations, sets virtual protective zones, and guides lasers for targeted processing, ensuring minimal energy input and preventing damage to sensitive areas.

Q: What was one of the most significant manufacturing challenges overcome during the mass production of these motors?

A: A particularly challenging aspect was the final assembly, known as the "marriage," where the stator is positioned between two rotors. Despite magnetic forces of up to 9 kN acting on the components, the stator must be aligned with a tolerance of less than 0.1 millimeters. This was overcome by developing an innovative control algorithm, sensitive sensor technology, and precise process guidance that makes high-frequency corrections in the final 0.5 seconds of the assembly.