Inside Mercedes-AMG’s axial flux motor architecture

The axial flux motor’s flat, disc-like geometry is what allows three units to fit inside the GT 4-Door Coupé’s compact drive units without the packaging penalty of a conventional radial flux motor

(Image courtesy of Mercedes-Benz)

Mercedes-Benz’s axial flux motor has entered series production for the first time, applied first in the AMG GT 4-Door Coupé. The top-performance GT variant (badged GT 63 in some markets) delivers up to 860kW (1,169hp) across three motors, two at the rear axle and one at the front, integrated into Mercedes-AMG’s compact High Performance Electric Drive Units (HP.EDU) rather than supplied as standalone motors, with the manufacturing complexity at Berlin-Marienfelde built to support the sustained-load case that peak output figures alone don’t address.

Motor topology and packaging

Mercedes-AMG describes the motors as integrated into HP.EDU drive units with compact planetary gearboxes, an axial flux layout with rotors sandwiching a central stator rather than the radial arrangement of a conventional motor. The rear motors exceed 13,000rpm and the front motor exceeds 15,000rpm, with the front unit functioning as a disconnectable booster: a disconnect unit decouples it during low-load driving to cut drag losses, then re-engages during acceleration or recuperation.

The production implementation is based on axial flux technology from YASA, the British specialist Mercedes-Benz acquired outright in July 2021, though axial flux as a motor topology predates that acquisition by decades. Independent academic work on axial flux machine simulation has flagged the YASA acquisition as symptomatic of wider industry interest in the format, alongside parallel efforts such as the EU MAXIMA modular axial flux motor project, though neither source speaks to Mercedes’ specific rotor or stator construction.

Battery integration

The GT 4-Door Coupé runs an 800V AMG High Performance Electric Battery, co-developed by AMG Affalterbach and Mercedes-AMG High Performance Powertrains in Brixworth, which also supports the AMG ONE hypercar programme. Mercedes-AMG states the pack supports 600kW DC charging, adding approximately 460km of WLTP range in around ten minutes. The company has not published cell-level chemistry, cell count, or pack capacity figures for this specific battery, nor cycle life or degradation data, which remain open questions for independent verification once customer vehicles accumulate real-world duty cycles.

Validation methodology

The GT 63’s 860kW and 1,169hp figures are peak outputs under AMG Launch Control. The more specific engineering claim, and the one Mercedes-AMG’s own endurance exercise was designed to test, is whether that output holds under continuous, repeated load rather than a single launch event. Mercedes-AMG says its CONCEPT AMG GT XX prototype ran 3,177 laps of the Nardò circuit at a constant 300km/h, recharging at average power levels around 850kW, covering roughly 5,300km per day in ambient temperatures the company describes as exceeding 35 degrees Celsius. This is the sustained-load validation that the production announcement itself doesn’t demonstrate, but that the Berlin-Marienfelde process count, 98 steps of which 35 are new worldwide, exists to industrialize at volume.

What production scale signals next

Berlin-Marienfelde’s production milestone and the Nardò endurance test both come from Mercedes-AMG’s own validation process. Independent data on cycle life, degradation, and how the drivetrain performs across ordinary customer duty cycles, as distinct from a controlled endurance run, has not yet been published. That is the gap engineers evaluating axial flux adoption elsewhere will want closed.

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