The effects of cold on electric car batteries and its consequences on their autonomy is a long-standing concern among potential buyers, be they from Tesla or any other brand. And he is partly right. After all, low temperatures do impact the performance and recharging of energy storage. But the story has nuances and is far from the fatalisms that certain “gurus” of the automotive environment try to impose.
The first thing to mention is that, for years, it has been proven that extreme cold conditions temporarily reduce the autonomy of electric cars. This, mainly, because the physical and chemical reactions that take place inside the batteries slow down when the temperatures are very low. Although the most serious effects are seen when the weather conditions are very severe, with the presence of snow and ice, for example.
But that is not the only variable that affects the batteries of Tesla electric cars or other brands. there are many Other “real world” constraints, which are not exclusive to winter, which in this case add to the cold to take its toll on autonomy. We’re talking about variations in driving speed, uneven terrain, use of cabin climate systems, and even battery degradation due to the age of the car.
Why does the cold affect the batteries of electric cars and reduce their autonomy?
Low temperatures affect the physical and chemical reactions that take place inside batteries. Something that is appreciated specifically when talking about conductivity and diffusivity. In the case of lithium ion batteries, extreme cold causes the electrolytic fluid within it to slow down. Therefore, the process that moves lithium ions from the anode to the cathode slows down and results in a drop in performance that, in the case of electric cars, results in a loss of autonomy.
Anna Stefanopoulou, director of the Institute of Energy at the University of Michigan, United States, explained to Wired in 2019 that batteries “are just like humans.” In what sense?, you may be wondering. In that they like to operate within a well marked temperature range, between 15 and 26 degrees celsius. And that if they have to work below 4 °C, or above 46 °C, they stop offering their maximum performance.
As we have already said, how marked the drop in the range of kilometers to be covered with the available charge will be will depend on the type of vehicle, the road conditions (orography, asphalt, unevenness) and driving. But the subject has been long studied, and the results They are not as apocalyptic as many times they want to believe.
In 2020, for example, the Norwegian Automobile Federation conducted an experiment in which he measured how much autonomy electric cars lost due to the effects of cold on their batteries. Results that would be compared to the official reach measured through the WLTP cycle. The agency took the 20 best-selling models in the country and concluded that, after the test, they had lost 20% of their autonomy, on average.
It is worth clarifying that the study was carried out with normal drivers, under the order to mobilize as they would on any given day. All the cars had been charged overnight under cover and had to start their journey with a cold start. That is, without preheating the battery or the passenger compartment.
In addition, they were used with Eco mode activated, with the heating at 21 °C and the seat climate control at its lowest setting. The trip included stretches of driving in the city, on freeways and on secondary roads. In all cases it started with a temperature of 3º C. However, the lowest record was -6 °C, with most of the trip with snow falling. Finally, the established speeds were between 60 and 110 kilometers per hour.
If we focus on Tesla’s electric cars, the effect of cold on their batteries and range was consistent. In the case of Model X, managed to travel 419.6 kilometers with its full charge, 17.24% less than its official autonomy of 507 kilometers under the WLTP cycle. The model 3 it did the same for 404.4 kilometers, 28% less than the 560 kilometers of range officially reported. Meanwhile he Model S it remained in the race for 469.8 kilometers, 22.98% below the declared autonomy of 610 kilometers.
Results that are not surprising
That the Model 3 was the Tesla vehicle whose autonomy was most affected by the cold is not surprising. After all, back then Elon Musk’s signature car did not yet include a heat pump to heat the passenger compartment, as was the case with its sister models. The company recently adopted this system in the aforementioned electric car from 2021, which reduced the energy consumption of the batteries for this purpose.
A video posted by Bjørn Nyland in late 2020 he demonstrated the improvement of the Tesla Model 3 with heat pump, compared to the 2019 variant, which used resistors for heating. The stationary tests —in the open air and at 3°C— to verify which could heat the passenger compartment more efficiently, were decisive. After three hours in camping mode, the 2021 model had consumed only 3% of the battery. While its predecessor had spent 10% of the available energy.
But the heat pump It was not the only change from Tesla to make the batteries of its electric cars work better in adverse climates.. In the case of the long-range, dual-motor Model 3, the version that went on sale in November 2021 arrived with a slightly higher usable battery capacity than its predecessor, available between 2018 and October 2020. We went from 75.0 kWh to 82 kWh.
The latter also made it possible to optimize its real autonomy, even at very low temperatures. According to collect EV Databasedriving of the aforementioned 2018-2020 model In cold climates —where the worst scenario contemplated was -10 °C and with the heating activated— it yielded a range of 435 kilometers in the city, 330 kilometers on highways and 380 kilometers on combined routes. In the case of the 2021 variant455, 350 and 400 kilometers of autonomy were obtained in the same scenarios and under identical conditions.
It is true that these numbers represent a considerable drop when compared to the range that could be achieved when driving in temperate climates. With an ideal scenario of 23 degrees and without air conditioning, a long-range Model 3 would reach between 660 and 700 kilometers in the city. Even so, the figures for driving at low temperatures continue to be more than enough to cover important journeys in extreme conditions.
The effects of cold on energy recharge
It has already been explained that extreme cold affects the batteries of electric cars, but they can also be seen at the time of recharging. In general, vehicles have management systems that prevent power charging from taking place at high speed if the battery is too cold. Something that can be especially challenging for vehicles that are often left parked on the street during winter nights.
It is true that Tesla has a robust system designed to keep the battery in an optimal temperature range, both in summer and winter, even when not connected to a charger. However, it is not to be trusted either. Let’s not forget that in severe cold conditions, part of the battery charge may not be available when driving. A measure intended to preserve the health of the accumulator. While the use of some functions such as regenerative braking may be limited or disabled until the vehicle warms up.
Thus, the image is a little clearer. Yes, the cold affects the batteries of electric cars and has an impact on their autonomy. But you’re unlikely to lose 75% range—a drop of ~500 kilometers to just 150 kilometers, for example—on a full charge. Even if you drive a Tesla of a certain age or under extremely unfavorable conditions. And no matter what the fatalists say when it comes to addressing everything related to electric mobility.