Impact of Winter on Electric Vehicles: Maintaining Range and Battery Health
As more drivers transition to electric vehicles (EVs), concerns about their performance in colder weather have become more prevalent. While extreme cold conditions in places like Antarctica and northern Siberia pose significant challenges, even merely very cold weather can affect EVs. This article explores how winter affects EV performance, focusing on battery drain, cabin heating, and overall driving range.
Will Your Electric Car Suffer in Winter?
Winter in very cold conditions can indeed present challenges for electric cars. However, it's important to note that most EVs are designed to handle temperatures that most people encounter. When faced with a temperature of -35°C, an electric car like the BMW i3, Nissan Leaf, or Tesla Model S will use a small amount of power to maintain battery and cabin temperatures. The primary use of power in these scenarios is to keep the car running, with just enough energy drawn from the battery to ensure reliable operation.
Start-Up Challenges
Similar to traditional gasoline vehicles, electric vehicles can face start-up challenges in cold weather. However, the solution often involves built-in features designed to mitigate such issues. For instance, heated battery warmers and block heaters are common in Canada, and similar features are standard in many modern EVs. These features help ensure that the vehicle’s battery is at optimal temperature for cold starts, making it much easier to operate in low temperatures.
Battery Chemistry and Cold Weather
The chemical reactions within EV batteries slow down as the temperature drops, reducing their efficiency. At extremely low temperatures (-20°C to -30°C), an EV's range can be significantly reduced. One of the primary ways to combat this issue is through the use of battery warmers, which can be activated to maintain battery temperatures above their critical operating range.
Increased Power Consumption for Heating
A key factor in reducing EV range during winter is the increased power required for cabin heating. The AAA conducted a study in February 2019 that tested several EV models, including the BMW i3, Nissan Leaf, Tesla Model S, Bolt, and e-Golf. These tests involved simulating standard EPA driving cycles at varied outside temperatures (20°F, 75°F, and 90°F or -7°C, 24°C, and 32°C) while the HVAC systems were either off or set to maintain a cabin temperature of 75°F.
The study found that when the HVAC is engaged, especially in traffic, the overall range of the vehicle can drop dramatically. This is because the power used to heat the cabin comes directly from the battery, reducing the available range for actual driving. However, at highway speeds, the impact is less pronounced as the car’s aerodynamics and motor efficiency play a more significant role in range reduction.
Advantages of Heat Pumps
Modern EVs, such as the Nissan Leaf, use heat pumps which are less effective in very cold temperatures. Heat pumps, while more efficient in moderate temperatures, can still consume a significant amount of power in extremely cold weather. This power consumption makes them comparable to resistive heating elements, which are less efficient at low temperatures.
Despite this, the Leaf with a heat pump still shows a 31% range reduction when the HVAC is on, compared to the BMW i3 with a 50% range reduction. This underscores the importance of minimizing HVAC use whenever possible to extend the driving range in cold weather.
Strategies to Maintain Range and Extend Battery Life
Electric vehicle manufacturers have recognized the importance of cabin heating in cold weather and have implemented several strategies to address this issue:
Heated Seats and Steering Wheels: These features reduce the need for HVAC use, which can be a significant drain on the battery. Reducing Speed: Lowering the vehicle's speed can also help extend the range, as higher speeds require more energy to overcome air resistance. Creative Use of Warmth: Strategies like warming up the car before setting off (e.g., using a block heater) can help prepare the battery and cabin for cold starts, reducing the strain on the battery and extending range.Furthermore, plugging the EV into a charger can help offset the power used for cabin heating, prolonging the battery's lifespan and extending the overall driving range.
Conclusion
While cold weather can pose challenges for electric vehicle drivers, these issues can be managed with the right strategies. The key is to understand the specific needs of the vehicle and the driving conditions. By staying informed and prepared, EV owners can continue to enjoy the benefits of these vehicles, even in the harshest winter conditions.
Additional Resources
For more detailed information, please refer to the following sources:
AAA Electric Vehicle Range Testing Report Cold Weather and Electric Vehicles: Natural Resources Canada