As temperatures plummet, drivers of electric vehicles (EVs) are likely to experience a significant decrease in their vehicle’s range. But why does this happen, and is there more to it than meets the eye?
Tests conducted by the Consumer Reports have revealed that the range of electric vehicles drops by an average of about 25% when driving on the highway in freezing conditions compared to warmer days. Unfortunately, the situation can be even worse during city driving and frequent stops, especially when the car’s interior cools down.
There are two main culprits for the range decrease: the battery and the driver. Both humans and electric vehicle batteries perform best within a similar temperature range.
Batteries function through chemical reactions, where electrons and ions move from one side of the battery to the other. When it gets too cold, these chemical reactions, including those occurring in the battery, slow down. This means that the driving range is reduced.
However, humans also don’t function as well in the cold. When driving on a chilly day, heating needs to be turned up. In reality, this is a much more significant factor in reducing the range of an electric vehicle than the impact of temperature on the battery itself.
In a gasoline-powered car, turning on the heater has almost no effect on fuel consumption. This is because internal combustion engines generate a lot of heat throughout the year, both in summer and winter. In fact, when a car burns gasoline while driving, more energy is converted into waste heat than into motion. Redirecting some of this additional heat into the cabin to keep passengers warm poses no problem.
In contrast, electric motors and batteries produce very little waste heat. This is one reason they are so efficient, as almost all the energy from the batteries is used for propulsion. However, when the cabin requires heating, the energy consumed for this purpose is subtracted from the kilometers that can be traveled. This means that the driving range can significantly decrease.
In Consumer Reports’ EV tests, conducting multiple short trips exacerbated the situation. Each time the vehicle stopped and the cabin cooled down, it had to be reheated upon restarting, consuming more energy.
Fortunately, most newer models of electric vehicles have highly efficient heating systems with heat pumps that help minimize energy losses. However, even these systems have their limitations and may not perform well in severe cold.
Charging electric vehicles also takes longer in low temperatures. Some electric vehicles significantly slow down their maximum fast charging in very cold temperatures to prevent battery damage.