National Electric Vehicles Sweden announced last week that it has bought Protean, a British manufacturer of in-wheel motors for electric cars.

In announcing the tie-up with NEVS, Protean said the acquisition will speed the rollout of its technologies in next generation electric and self-driving cars, and "paves the way for NEVS to deploy Protean Electric's in-wheel electric drive technology."

In-wheel motor technology has been considered a big breakthrough for electric cars, because they could dramatically reduce the number of moving parts in a vehicle and increase designers' flexibility in building cars by reducing the need for blocked-out spaces inside the car's metal shell to house the motors.

They've been slow to take off, however, for a variety of reasons. The most notable of those is that they move the weight of the motors off the body and onto the individual wheels, which can lead to a bumpy ride and diminished handling as well as durability concerns for the motors themselves. When the wheel slams into a pothole, it isn't just the tire and wheel that are vulnerable; the motor is, too.

In addition, restricting the motors to the inside diameter of the wheel limits options for gearing, which in most applications will limit acceleration, even with instant torque from an electric motor in each wheel. 

Still, the potential advantages are compelling enough that several companies are still working on them and looking for a commercial outlet.

NEVS could prove to be the right fit for that. It includes what remains of Saab, purchased in January by Hong Kong conglomerate Evergrande, which has big ambitions to become an electric-car powerhouse. It also owns portions of Faraday Future and Swedish Supercarmaker Koenigsegg