A British company has developed a range of axial-flux motors which, it claims, offer a higher power density than any other motor currently available for automotive applications. Woking-based Evo Electric says that its technology will dramatically improve the cost, performance and efficiency of hybrid and electric vehicle powertrains.

According to Evo, the motors (also available in a generator format) have demonstrated a peak power density of 5kW/kg (2.5kW/kg nominal). This is 33% better than its previous motors and puts them well above the US Department of Energy’s power density targets for 2015 and 2020. The weight measurements included all of the motor and generator components, including their housings, shafts and resolvers.

Evo says its machines will also cost less to manufacture than other permanent-magnet motor/generators, because of their higher power and torque densities (and thus, lower material costs) and their simple, yet robust, designs optimised for low-cost, high-volume manufacturing. The technology has undergone extensive reliability, endurance, shock and vibration testing, including road tests.

Evo is collaborating with automotive partners to develop drive systems and other products for various vehicle platforms. For example, it has supplied high-torque machines with peak outputs of 200kW/660Nm (100kW/240Nm nominal) and weighing only 40kg to several hybrid and electric vehicle developers.

Lotus Engineering is using Evo motor/generators in its Evora 414E Hybrid concept vehicle which it unveiled at the Geneva Motor Show earlier this year. The vehicle has two Evo drive motors, each providing 152kW of power and 400Nm of torque, and a 35kW range extender system based on Evo’s generator technology.

Evo is also developing larger models for commercial vehicle applications and an ultra-compact motor suitable for light-duty electric vehicle applications.

“Evo’s axial-flux technology is based on a new paradigm of machine design,” says the company’s CEO, David Latimer. “We are committed to bringing this exciting technology to market and, by doing so, to further accelerate the global trend toward powertrain hybridisation and electrification and, more generally, to lower-carbon vehicles.”

Evo Electric was founded in 2006 by Dr Michael Lampérth and Dr Malte Jaensch to commercialise an axial-flux technology originally developed at Imperial College in London. Commercial activities began in June 2007 using seed capital from private individuals and from professional investors including Imperial Innovations, which helps scientist-entrepreneurs to commercialise their ideas and has exclusive access to scientific and technological developments from Imperial College.

Initially, Evo operated from the Imperial Incubator which provides office and laboratory space for new companies. It soon relocated to new premises in Woking, Surrey, where its facilities include high-power machine testing facilities, a prototyping workshop and an assembly area.