Electric Cars

Why EVs Weigh So Much!

July 18, 2021

Why Are Electric Cars So Heavy? 

You probably already know the answer to the question of why electric vehicles weigh more than gasoline-powered ones. Battery packs are just really heavy!

Take the new all-electric GMC Hummer EV that’s coming by the end of 2021. The Edition 1 version, which has lots of batteries for additional driving range and power, weighs over 9,000 pounds. That's roughly three times the weight of a Honda Civic.

The Edition 1 has the longest driving range and the most power of any version of that truck, and long range and big power mean a lot of heavy batteries. Those heavy batteries, plus heavy-duty off-road parts, are the reason it weighs so much, General Motors says.

Other electric vehicles also weigh more than similar gasoline-powered models. Ford’s new F-150 Lightning all-electric pickup truck weighs about 1,600 pounds more than its gas-powered F-150 variant. Similarly, the all-electric Volvo XC40 Recharge SUV weighs about 1,000 pounds more than a gas-powered Volvo XC40.

Heavy Batteries

Vehicles getting heavier is hardly new, nor is it unique to electric vehicles. The average weight of passenger vehicles has been increasing for the past 40 years, according to a report from the Environmental Protection Agency, from an average of about 3,200 pounds to nearly 4,200 pounds. That's largely due to consumer preferences shifting towards trucks and SUVs in recent years.

That has important implications for safety, but it's more complicated than the traditional thinking that revolves around issues of mass and speed. In terms of crash safety, that extra battery weight actually helps people inside electric vehicles. Insurance claim statistics show that people in electric vehicles are less likely to be injured in a crash than people in otherwise similar gas-powered vehicles.

This could be attributed to the fact that electric vehicles aren't carrying a large metal engine under the hood, so they have more empty space that can cushion occupants. But the same injury claims trends hold true for hybrid vehicles, says the Insurance Institute for Highway Safety. Hybrids also have added weight from batteries as well as an engine under the hood. So the difference seems largely attributable to sheer mass.

But that extra weight can be bad news for people who get hit by electric vehicles, as the added impact force gets transferred to the other, lighter gasoline-powered vehicle.

Physics 101

It's a matter of simple physics. When two moving objects hit one another, the heavier one will tend to carry on in more or less the direction it was going. The lighter one, on the other hand, will change direction abruptly. Even if that lighter vehicle doesn't get smashed in, that jarring deflection is bad for the people inside. Meanwhile, for the people in the heavier vehicle that just punches its way through, that extra weight can be a lifesaver.

In developing the Hummer EV, a lot of thought went into minimizing the chances of a crash for the sake of both the Hummer's occupants and others on the road, according to GM. For instance, a variety of collision avoidance technologies, such as lane keeping assist and pedestrian detection, which are available on many modern vehicles, will be standard equipment on the Hummer EV.

Weighing In

Apparently, it's not weight in itself that's the issue from a safety standpoint. It's the differences in weight between vehicles. That, too, is something that has always existed as long as small cars have shared roads with heavy trucks. “When a small car and a truck meet in a crash, the weight difference there is so large it would hardly make a difference if the truck was electric,” says David Zuby, senior vice president for vehicle research at the IIHS. “But when two passenger vehicles crash into each other, if one of them is carrying 1,000 pounds of batteries, that could make a difference in the outcome.”