The axial flux electric motor introduced by Yasa demonstrates that it is possible to significantly exceed current power density standards in production electric motors. The automotive industry, and potentially others, may see new design opportunities arise from these advancements in electric propulsion technology.
Yasa, a UK-based company specializing in next-generation electric motors, has developed an axial flux electric motor that recently set an unofficial world record. The motor delivers 550 kW of power (738 hp) from a unit weighing just 13.1 kg, resulting in a specific power density of 42 kW/kg. This output is approximately twice the power of existing production electric motors, placing this technology at the top end of power-to-weight ratios currently available.
Unlike the mainstream radial flux motors used in most electric vehicles, Yasa has developed an axial flux architecture, where the magnetic flux runs parallel to the axis of rotation. The main consequences of this design include different aspects. For instance, greater power and torque density: Axial flux motors can deliver up to four times the torque and twice the power of standard motor designs. Then, there is compactness and lower weight: dimensions can be reduced by up to 50% compared to conventional motors, with significant weight savings.
Other asset are improved efficiency and cooling, because the motor uses shorter windings and employs direct oil cooling, allowing high power output under sustained stress, and production feasibility: the recorded motor does not rely on exotic materials or highly advanced manufacturing processes, enabling potential mass production for high-end vehicles.
Applications and Industry Implications
The motor is already used in models such as the Koenigsegg Regera, Ferrari SF90 Stradale, and the Mercedes Vision One-Eleven concept. Mercedes-Benz has also acquired the company, indicating plans to integrate the motor on a larger scale into future high-performance electric models.
Yasa’s motors are reportedly ready for scalable production (up to 50,000 units per year), without the need for expensive raw materials, allowing wider adoption of high power density in electric vehicles beyond the supercar segment.
