Renault Group has acquired a 21% minority stake in Whylot, a company based in the Lot region of France that has developed an innovative axial flux automotive e-motor. This acquisition of a stake in the French start-up reinforces the existing strategic partnership between the two companies.
Renault Group has previously signed a partnership with Whylot to develop and industrialize on a large scale an axial flux e-motor. This technology will be applied to electrified and electric powertrains, with the objective in particular in hybrid powertrains of reducing costs while saving CO2 emissions of 2.5 g/km of CO2 according to the WLTP standard (for passenger cars in segments B/C).
Renault said that this equity investment will enable Renault Group and Whylot to position themselves in the coming years as leaders in the development and industrialization of innovative and affordable electric motors and to support the very strong growth of the electrified vehicle market in France and Europe. Renault Group will be the first mainstream manufacturer to produce an axial-flow electric motor on a large scale, starting in 2025.
Axial flux motors offers a number of advantages in theory to the more common radial flux motor, including higher torque; in other words, for a given required torque, an axial-flux machine can use fewer magnets. Despite the advantages, however, radial flux motors dominate the market.
Whylot notes that a number of factors makes axial flux machines difficult to accomplish. These include a very high linear speed, placing high demands on the mechanical strength of the magnets; thermal management for the rotor; and difficulties in manufacturing the stator at high cadence on a production line.
Whylot axial flux motor
In response, Whylot has:
Upgraded the rotor. Conventional axial flux rotors provide high linear speed and heat up at high power output; the whole system becomes unstable and suffers from power loss. Whylot uses a composite material that is easy to manufacture and is strong and durable. A honeycomb grid holds the magnets; there is no heat and no demagnetization, as verified in simulation.
Upgraded the stator. The stator’s modular structure makes winding easier and suitable for mass production. Two stators on one rotor result in double excitement on the rotor; i.e., fewer magnets for the same performance with a resulting lower cost.