Yasa claims record motor power density, doubling previous figure
18 July 2025 
Yasa, the UK-based developer of axial-flux electric motors, claims to have achieved the highest power density ever recorded for any electric motor. In recent test trials, a prototype motor delivered 550kW of power from a 13.1kg package – equivalent to 42kW/kg.
This power density is said to be almost twice as high as the previous benchmark.
Yasa says that while the record is unofficial, it represents a major milestone for what’s possible at the cutting edge of practical, high-performance electric motor design. The test was performed on a standard rig, with further validation planned on a full-capacity dynamometer later this year.
The record-breaking performance was achieved without the use of exotic materials such as cobalt-iron laminations, Litz wire, or 3D printing. Yasa says the technology could be scaled to produce 10,000–50,000 motors a year at a “viable” cost.
The company adds that this is the first in a series of technical breakthroughs that it expects to announce in the coming months.
Yasa claims that its axial-flux powertrain technology delivers the highest power/torque densities in its class, for the smallest size and weight.
Since 2021, the company has been a wholly owned subsidiary of Mercedes-Benz Group. It designs and manufactures high-performance electric motors and power electronics mainly for automotive applications, employing more than 400 people at sites in Oxford, Bicester and Welshpool.
