EV Motors

EV Motors

I see so much time and money put into all these electric vehicles to improve their charge times, power capacities and range. My question is, why haven't any companies redesigned the electric motor? They all seem to stick to the same basics of motor design that have been used for over a 100 years now. Why can't the electric motor be made more efficient? It just seems to me that some basic laws of physics are ignored in the designs that could greatly improve on the basic motor designs.

evanstumpges | 14 December 2012

Tesla's motors have an efficiency of around 90%. The most efficient electric motors I'm aware of are CSIRO solar car motors which can be up to ~96% efficient. These hub mounted, axial flux "pancake" motors are based on a halbach array of permanent magnets. This extra 6% of efficiency doesn't come cheap though. Permanent magnets can improve efficiency but are generally cost prohibitive for high powered motors like Tesla uses.

That's not to say that electric motors are perfect and there is no room left for improvement, but starting from 90%, even significant breakthroughs in motor technology would prove fairly insignificant for the overall system.

While it's true that motor design has generally been fairly constant for the past century, Switched Reluctance Motors (SRM) are actually undergoing substantial new R&D right now since they offer great potential to reduce cost while meeting or beating the efficiency of the tried and true induction motor. I think this might be a technology that Telsa could pick up in the long term. Right now their biggest focus is on getting the Model S to customers as fast as possible, so I doubt improving motor efficiency is very high on their immediate to do list.

Brian H | 14 December 2012

Indeed. If motors were free and had 100% efficiency, it would make little difference to Tesla's designs or costs.

SchwenLarson | 16 December 2012

Even if they weren't free, Brian...having 100% efficiency would be a beautiful thing.


Brian H | 16 December 2012

And you could feel even less guilty in your MS "Drivin' Around"? ;)

Jolinar | 18 December 2012

as Brian H said, it won't make much difference... if motor have 90% efficiency and range is 265 miles, then with 100% efficiency it would grow only to 294 miles. You will get much more range by making battery and rest of the car lighter (including motor of course), lowering rolling resistance and drag, charging efficiency and so on. Higher eficiency motor isn't so important, it would make it easier to cool though.

Jolinar | 18 December 2012

*improving charging efficiency....

vjekoc | 1 August 2013

as Brian H said, it won't make much difference