/ 6 April 2024

Electric vehicles have a weighty problem

Electric vehicles are heavier than internal combustion engine-powered ones because of their batteries, and their weight affects their steering and braking.

The subject of electric cars is a broad one. We have spent considerable word counts mansplaining hybrids, plug-in hybrids and fully electric cars, as well as providing advice on what to consider when purchasing an electric vehicle.

EVs are more friendly to the environment than internal combustion engine-powered vehicles and they are improving in terms of range, price and technology. 

However, there is one significant challenge that remains to be addressed — the weight of these vehicles. EVs are generally heavier than cars powered by internal combustion engines (ICE) because of the large battery packs located beneath the floor. 

For instance, let’s look at the BMW 420d Gran Coupé, which has a reasonable weight of 1 705kg. In comparison, its electric counterpart, the i4 M50, weighs 2 215kg, because of its high-capacity 83.9kWh battery pack.

On that note, the GMC Hummer EV is classified as a class three medium-duty truck in the US of America, due to its massive weight of just over four tonnes. 

But why do EVs have such a weight disadvantage? After all, they are only batteries, right? 

Well, yes, but there are also other factors to take into account, such as electric motors and the additional reinforcement of the suspension system which is necessary in order for it to carry that extra weight. 

As for the battery packs, they are usually made of lithium-ion cells, which are quite heavy. 

These batteries store the electrical energy that propels the vehicle. In essence, giving a car hundreds of kilometres of driving range means slinging a huge, heavy battery to the bottom of it. 

Manufacturing giants such as Toyota and Stellantis are working around the clock to find a workable solution to reducing the weight of these batteries. 

Stellantis, in particular, has set an ambitious goal to reduce the overall weight of EV batteries by half by 2030 by developing lighter and more affordable lithium-sulphur batteries, which is a key feature of the new Volvo EX30 as well. 

According to the multinational automotive manufacturing corporation, these types of batteries make use of less exotic materials than the lithium-ion batteries of today. 

This initiative is largely driven by its investment in Lyten, a company specialising in lithium-sulphur batteries, a promising alternative to the traditional lithium-ion batteries. 

Until manufacturers find a viable way to reduce the weight of the batteries in electric cars, they will persist in their inefficiency. 

What are the penalties for a heavy EV car? 

The heavy batteries contribute to significant understeer, increased inertia and added stress on the suspension system. 

Back to the matter of efficiency. The weight of a car affects its real-world driving range. 

A heavier car necessitates more energy for movement which, in turn, affects its range, due to the increase in energy demand. This can lead to the rapid depletion of the battery and more frequent visits to the charging station.

During our testing of the BMW iX1 xDrive30, which has a rated weight of 2 010kg, and is fitted with a 64.7kWh battery pack, we were able to drive up to 380km on a single charge. 

It’s important to note that the relationship between the vehicle’s weight and its range can be seen as linear because automotive engineers usually account for battery capacity in proportion to the vehicle’s size. 

For instance, a large vehicle such as the Lotus Eletre R employs a 112kWh battery pack that feeds power to two electric motors to help carry the 2 640kg behemoth. 

EVs tend to understeer because of the weight of the battery packs and  weight is distributed differently from ICE-powered cars. 

The vehicle’s weight can have an impact on the handling characteristics, particularly cornering. 

For instance, the BMW i4 M50, which weighs 2 215 kg, demonstrated a tendency to understeer well before the perceived limit during our 2022 Speed Week event around Slaaihoek in Mpumalanga. 

Another disadvantage of EVs weighing more than their ICE counterparts is inertia, simply because the heavier the car, the longer its braking distance becomes. This means a heavy car takes longer to stop than regular cars, posing a safety risk in emergencies. 

Greater inertia can also cause more wear and tear on the car’s components, such as brakes and tyres. 

Though EVs have some of the best passive and active safety systems in place, several experts and organisations have raised concerns about the increased severity of accidents. 

A study estimates that a 450kg increase in vehicle weight has the potential to result in a 47% increase in fatality risk. 

Furthermore, the risk to vulnerable road users, such as pedestrians, cyclists and motorcyclists, is a serious concern. The additional weight that EVs carry can result in more severe injuries in a collision with these road users.

Finally, the higher weight of EVs can put additional strain on the suspension system, affecting the vehicle’s performance and longevity. 

Carmakers are working feverishly to address these concerns as EV adoption is growing at a rapid rate.  EVs represent a crucial step forward in terms of sustainability, as the world is collectively working towards a single goal — net zero emissions. 

It is essential that the aforementioned challenges are solved quickly in order to enable a smooth transition to a more sustainable mode of transport.