Jon Bentley knows that EVs are the heaviest cars on the road, but is hopeful that technological remedies can also help in other ways
It’s common knowledge that electric cars have a weight problem. On average they’re around 30% heavier than their combustionengined equivalents, a burden that’s mainly down to the batteries. It’s an issue manufacturers are working hard to eliminate through developments like solid state cells, new battery technologies and more efficient packaging.
What’s less well-known is that there’s an equally furious battle going on to reduce the weight of the electric motors that turn the batteries’ energy into motion. Every part of the motor is being slimmed down. Rotor and stator laminations made out of steel sheets can be replaced by lighter and cheaper soft magnetic compounds produced by injection moulding. Mild steel motor shafts can be switched to ones made from carbon-reinforced plastic and stainless steel. Motor windings can be lighter and more compact.
On the face of it, this doesn’t look like a priority. Electric motors are normally lighter than the equivalent combustion engine – around 50kg as opposed to 200kg for the ones found in a typical small car. But there are still dividends in weight paring. Every little bit saved helps mitigate the weight of the batteries, reducing worries like the extra particulate pollution produced by heavier cars’ tyres and fears that old concrete car parks will collapse under the poundage of bloated EVs.
For me though the biggest advantage of lighter and smaller motors is that they will find their way out from the body of the car, into its wheels. In-wheel motors have usually added too much unsprung weight, affecting ride and handling, and have not developed enough power. But those disadvantages are being overcome.
Lighter and smaller motors will find their way out from the car’s body, into its wheels
What can be achieved with in-wheel motors was demonstrated at CES this year. The Hyundai Mobion, based on the Ioni
