Why Are EVs Shaped the Way They Are?
Those unmistakable electric vehicle curves are all about one thing—range.
When it comes to designing an electric car, maximizing range is a paramount priority. Carmakers can do this in several ways. Improving driver behavior and making the battery larger are two big ones, but perhaps the one that’s most immediately apparent when you’re actually looking at an electric vehicle (EV) is the shape.
EVs are generally designed to be as slippery as possible (the GMC Hummer EV being a notable exception), so they can slide through the wind, rather than beating it into submission the way a helicopter might. Just how slippery? The solar-powered Lightyear 0 is the world’s most aerodynamic production car, with an astonishingly low drag coefficient of 0.175. And other EVs—the Mercedes-Benz EQS (0.20 drag coefficient) and the latest Tesla Model S (0.208 drag coefficient) in particular—aren’t far behind.
It used to be that car designers would simply draw some lines on a piece of paper, mock up their design in clay, and then go put the vehicle on sale. These days, car designs must undergo rigorous aerodynamic simulations and testing to maximize performance, range, and efficiency.
Looking at the Lightyear 0, the Mercedes-Benz EQS, and the Tesla Model S, you can see they all have the same basic shape: rounded at the front, with gentle slopes up a long windshield, and then the same at the back. The Lightyear 0 is the most extreme of the three, using a long rear overhang to minimize drag at the rear end.
Aerodynamicists can write Ph.D. theses on how to minimize drag on cars, so there’s clearly more to it than this, but here’s the upshot: EVs (and all cars, really) are designed the way they are to reduce drag and to balance aesthetics and practicality. If you look around a new car lot and notice the absence of boxy cars, it’s because they were replaced with more aerodynamic designs.
Skinny Tires Reduce Aerodynamic Drag
Tires are the other major influencer of EV efficiency. More rolling resistance means less range. The first way to reduce rolling resistance is to change the chemical composition of the tire. Most tire manufacturers are starting to make tires specifically formulated for electric vehicles, aiming to reduce rolling resistance and maximize range without sacrificing the grip needed to stop, turn, and accelerate effectively.
The second way to reduce resistance is to make the tire’s contact patch smaller by making the tire narrower. The contact patch is the amount of tire that makes physical contact with the pavement at any given point—it’s literally where the rubber meets the road. Making the contact patch smaller reduces the amount of friction between the tire and the road, which helps improve range. This does reduce performance by a small amount, which is why sporty electric cars have big tires—and reduced range as a result.
Most electric cars also use a so-called skateboard design for their underpinnings, which puts all of the drivetrain components (motors and batteries, mostly) in a flat plane at the base of the car.
This means the vehicle doesn’t need to be designed around physical components like the engine and fuel tank, which expands design possibilities for the interior. That’s why many electric cars have a completely flat floor and can feel like much larger vehicles inside than they might appear from the outside.