When drivers of future Mercedes-Benz AMG models hit the accelerator of their electric performance cars, they will get extra power out of the batteries from something that sounds straight out of the movie Back to the Future.
No, not flux capacitors, but axial flux motors.
Axial flux motors are much smaller than predominantly used radial motors yet pack a more powerful punch.
High-end motors like these will be crucial to brands like AMG and Ferrari as they race to electrify the high-performance vehicles that earn prestige and bumper profits.
All EVs offer the sensation of instant acceleration, from Nissan’s Leaf to Tesla’s Model S Plaid.
Whereas in the combustion age, quicker times off the line and higher top speeds were achieved with more engine cylinders, manufacturers will differentiate performance EVs by getting the most out of batteries with lighter and more efficient motors.
“The power-to-weight ratio is really a record number, and much better than conventional motors,” Markus Schaefer, Mercedes’s chief technology officer, said of the automaker’s upcoming AMG electric vehicle platform. “It will make use of the small size of the motor.”
With each press of the accelerator, EV drivers push hundreds — and in some cases thousands — of amps of electric current to copper coils. When these coils are energized, they become electromagnets with attractive and repulsive forces. The magnetic force created by a stationary stator surrounding a rotating rotor produces the torque that turns the wheels of the vehicle.
In axial motors, rather than have a rotor spin inside a stator, disc-shaped rotors spin alongside a central stator. This leads the flow of current — the flux — to travel axially through the machine, rather than radially out from the center.
Since the motor generates torque at a bigger diameter, less material is needed.
Yasa, an Oxford, England-based manufacturer of motors used in Ferrari’s SF90 and 296 GTB plug-in hybrids, uses just a few kilograms of iron for its stators, reducing the mass of the machines by as much as 85 percent.