Most automobile enthusiasts are well aware that frigid winter temperatures can adversely affect the total driving range of an electric vehicle (EV). This quirk is often cited by proponents of gasoline-powered cars as a reason why EVs may face challenges in certain regions. However, recent research suggests that extreme heat can have similar, if not more significant, impacts on EV range.
According to a study conducted by an analytics company in Seattle, ambient temperatures exceeding 38 degrees Celsius can dramatically reduce an EV's battery range. The study involved testing thousands of EVs in various climates and found that some of them experienced a range reduction of up to 31 percent when the temperature crossed the 38°C mark. In contrast, testing in milder temperatures of around 32°C resulted in a more modest range loss of approximately five percent.
The underlying reason for this range reduction lies in the current state of battery technology. A technical director from the University of Michigan explained that triple-digit temperatures can lead to the breakdown of the "passive emission layer" on the battery anode, causing the consumption of the battery's liquid electrolyte. Furthermore, running the ventilation systems in an EV, whether for heating or cooling, can impact range because some of the battery's energy is diverted to cabin comfort rather than propulsion. After all, energy has to come from somewhere.
The author of this article recently embarked on a road trip in the American Southwest, experiencing firsthand how scorching temperatures, nearing 50 degrees Celsius, with single-digit humidity can affect a gasoline-powered vehicle. The air conditioning ran continuously, and the cooling fans were frequently louder than a helicopter over Huế. While fuel efficiency suffered, the gasoline car's range was not cut by a third.
However, the same cannot be said, at least not yet, for electric cars. Still, this has not dampened the enthusiasm for EVs, as they continue to gain popularity, even in sweltering regions.
The positive takeaway from this research is that the impact on EV range appears to be more logarithmic than linear. In other words, moderate temperatures around 30°C do not significantly stress batteries to the point of headline-grabbing reductions. Additionally, advancements in solid-state batteries are promising, as some solid electrolytes are believed to be less sensitive to extreme temperature fluctuations compared to their liquid counterparts.
Nonetheless, this research serves as a reminder of the challenges EVs face when it comes to extreme temperatures, especially as global temperatures continue to rise.
