Cold weather reduces efficiency of all vehicle types, not just EVs. According to FuelEconomy.gov, conventional gasoline vehicles typically have a 20% reduction in fuel economy at 20° F. However, it is often more noticeable with an EV and is especially concerning for all-electric vehicle drivers who need to know they have enough range to reach their travel destinations.
Range Your Electric Vehicle could Lose Due to Cold Weather
Electric vehicles’ performance declines with falling temperatures. Additionally, the driving range fell by 12% at 20 degrees Fahrenheit compared to 75 degrees Fahrenheit, following testing done by the American Automobile Association (AAA) in 2019. When the cabin heating was turned on, this reduction in range rose to 41%.
It is safe to state that cold weather causes your electric vehicle’s range to diminish. Why does this happen, though?
Why Does the Range of Your EV Decrease in the Winter?
We all know, batteries don’t last forever. This is due to other reactions that consume the electron-rich Lithium atoms, degrading battery performance. These reactions occur at different rates at different temperatures.
Therefore, cell manufacturers define a range of temperatures in which batteries can function optimally. For lithium-ion batteries, the discharge temperature is between -4 and 140 degrees Fahrenheit, while the charging range is between 0 and 45 degrees Fahrenheit.
This clearly shows that lithium-ion batteries can discharge at sub-zero temperatures, but charging them at the same is not advised. Also, lithium-ion batteries offer the best discharge performance at room temperatures, and in extreme situations, their performance degrades.
The reason for this degradation is as follows.
When you charge your lithium-ion battery, the charger pulls lithium ions from the cathode, converts them to lithium atoms by adding an electron, and embeds them into the graphite on the cathode.
When the temperature decreases, the lithium atoms don’t intercalate in the graphite; instead, they coat the surface of the anode causing lithium plating. This lithium plating phenomenon converts the otherwise electropositive lithium atoms into an inert metal. Due to this, the number of lithium atoms available for providing free electrons goes down—decreasing the battery’s performance.
On the other hand, when your battery discharges, the lithium ions have to move from the anode to the cathode. During this process, the ions have to move through the electrolyte, but when the temperature decreases, this process slows down as the resistance of the electrolyte increases. This increase in resistance reduces the range your EV offers.
In addition to the factors given above, the battery is responsible for keeping the cabin warm when the weather outside is cold. Due to this, the battery has to run both the vehicle and the heating system, reducing the range further.
Points to consider for efficient EV Experience in the Winter
Now that we have a basic understanding of why the performance of your EV goes down when the temperature goes below sub-zero, we can look at how you can improve your EV experience in winter.
1. Refrain from Fast Charging Your EV during freezing winter
As explained earlier, Lithium plating is a battery’s biggest enemy during cold weather conditions. Not only this, but the phenomenon increases when the charging current is high.
Therefore, it’s advised that you should not fast charge your electric vehicle when the ambient temperature is below freezing
2. Charge Your EV Slowly at Night
If you plan to travel long distances on your EV, it’s best to charge it to the brim at night using level 1 charging. Not only will this provide you with a full charge in the morning, but it also provides a slow charging current that won’t damage the battery.
Not only this, but if you don’t have a heated garage to charge your EV, the slow charging will keep your battery warm, protecting it from cold weather conditions.
3. Be Prepared for Longer Charging Time
As the electrolyte on your battery gets sluggish in colder weather, it takes longer to charge. Therefore, you should be prepared for a longer charging duration while charging in colder weather conditions.
4. Don’t Leave Your Battery Discharged in Cold Weather Conditions
If you are not going to use your vehicle for a long duration, it’s advised to charge it to 70 percent before storing it. Doing this will reduce the reactions which degrade your battery’s health.