We have all heard the term ‘there is no replacement for displacement’, however, this does not stand true anymore in the current EV age. In fact, with electric vehicles what holds true is ‘the smaller the better.’ At least that is what performance oriented automakers such as Mercedes-AMG and Ferrari believe. Introducing the ‘axial flux motors’, which are much smaller than the widely used radial motors in EVs and yet they pack a more powerful punch. Here is everything you need to know about this technology of hyper EV future.
Unlike higher displacement and more cylinders burning fuel in ICE vehicles, EVs by nature perform better with their instant acceleration, be it a Tesla or India’s Nexon EV which has a 0-100 kmph time of under 10 seconds. So how can manufacturers differentiate a performance EV from a conventional one? As per a Bloomberg report, Mercedes-Benz and Ferrari have turned towards axial flux motors to get that extra load of performance out of battery packs.
How does it work? This is where it gets a little complicated but we will try to keep it as objective as possible.
Generic EV radial motors consist of copper coils and a rotor. When electricity is delivered to the copper coils, the coils get energised and turn into an electromagnet charged with both attracting and repelling forces. The magnetic force is what produces the torque in the rotor that spins alongside a central stator which then turns an EVs wheels. For a better understanding, below is a graphic representation of a typical BLDC motor, widely used in EVs. (Image source: Wikipedia)

However, conventional EV motors are still heavy and play an important role in a vehicle’s power-to-weight ratio. On the other hand, an axial flux motor does not have a rotor to spin alongside a central stator, it leads the electricity directly to the flux. This means that the current is travelling axially through the motor rather than radially from the centre. The motor is slimmer, lighter and generates torque at a bigger diameter. Overall, an axial flux motor setup can be up to 85 percent lighter than a conventional setup.

Origin story and current applications:
The axial flux motor was designed by England-based Yasa motors, a brainchild of Tim Woolmer, who had been commissioned by Jaguar Land Rover to produce a hybrid-electric performance car that would rival the Porsche 918 Spyder. While that project eventually got cancelled due to financial constraints, Yasa’s axial flux motor made its way into other hypercars such as the hybrid Koenigsegg Regera along with the Ferrari SF90 and 296 GTB plug-in hybrids. More recently in July 2021, Mercedes-Benz ended up acquiring Yasa motors and are expected to use the technology for their performance based AMG EVs by 2025.

However, this does not mean that performance EV manufacturers will completely drop radial motors. It would rather be utilised on a case to case basis. Cars that need higher top speeds will feature both radial and axial flux motors. Models that need to have better handling dynamics could use only the axial flux motors.