UK-based electric motor manufacturer Yasa, a subsidiary of Mercedes-Benz, has achieved an unofficial new world record for electric motor power density. The company reported a short-term peak output of 750 kW from its latest axial-flux prototype, equating to 59 kW per kilogram.
The milestone marks a major leap from Yasa’s July performance, when the same prototype design delivered 550 kW at 13.1 kg, corresponding to a density of 42 kW/kg. The newly tested version, weighing slightly less at 12.7 kg, produced 40 percent higher power density, confirming Yasa’s position at the forefront of axial-flux motor innovation.
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Yasa said the latest prototype was developed not solely for short-term output but also for sustained performance, with estimated continuous power in the range of 350–400 kW. The company added that further technical details will be disclosed in upcoming updates. The recent testing was conducted on a larger facility designed to handle high-output trials, following earlier experiments that had already exceeded the 500 kW target.
Yasa Chief Technology Officer Tim Woolmer described the achievement as validation of the company’s next-generation axial-flux technology, noting that the motor combines exceptional power density with scalable materials and processes suitable for high-performance automotive applications. Chief Executive Officer Jörg Miska said the result underscores Yasa’s leadership in electric motor design, adding that its axial-flux architecture achieves roughly three times the performance density of conventional radial-flux motors.
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Unlike traditional radial-flux designs, Yasa’s axial-flux motors align the stator’s magnetic field parallel to the rotation axis, resulting in a compact, disc-like form that enhances efficiency and reduces weight. These characteristics make the technology particularly attractive for electric and hybrid sports cars, where size, power, and thermal management are critical factors.
Founded in Oxford and acquired by Mercedes-Benz in 2021, Yasa’s technology has already featured in the Mercedes-Benz Vision One-Eleven concept and the AMG GT XX prototype, which gained attention for its high-performance drivetrain. While Yasa’s axial-flux systems are not yet deployed in Mercedes-Benz production EVs, they have been integrated into several hybrid supercars, including models from Ferrari, marking an early step toward wider adoption of lightweight, high-efficiency propulsion systems.
Source: Electrive