This article from IEEE Spectrum on YASA Limited (now part of Mercedes-Benz AG) details how axial-flux electric motors, sometimes called “pancake motors,” are entering mainstream high-performance applications, challenging the long-dominant radial-flux motors.
YASA’s recent prototype reaches a claimed peak output of 750 kW (1,005 hp) while weighing just 12.7 kg (28 lb), delivering a power density of 59 kW per kilogram, roughly three times that of current radial-flux designs. The motor is already in prototype supercars and high-speed EVs, and Mercedes is scaling production to perhaps 100,000 units annually.
What explains the leap? The axial-flux geometry flips the magnetic flow: rather than radial from the shaft outward, the flux travels parallel to the shaft. Combined with a yokeless, segmented armature and dual-rotor layout, this architecture boosts torque, shortens the magnetic path, and improves cooling. YASA’s stator uses soft-magnetic composites instead of heavy iron yokes, saving weight and reducing losses.
For engineers designing EVs, the implications are strong: smaller active components, lighter motors, more flexibility in packaging, reduced battery mass, and potentially lower overall vehicle weight (YASA cites savings of up to ~200 kg in vehicle mass).
The technology is no longer limited to hypercars. With Mercedes’ investment, the design is headed toward higher-volume electric vehicles. The shift indicates a broader change in propulsion architecture: motor design is becoming a key enabler of vehicle weight-reduction and higher performance, not just battery chemistry or aerodynamics.