Extreme weather can affect electric vehicle battery performance, potentially limiting its range and how quickly the battery charges. But why? The answer comes down to the chemistry inside an electric car’s battery pack, your driving habits, and other factors.
How Extreme Weather Affects an Electric Car's Battery
Very cold or hot weather—generally defined as below 20 degrees or above 95 degrees Fahrenheit, according to AAA—can cause a drop in EV range. The change is temporary and the range will rebound as the temperature warms up or cools down, but as Recurrent notes, "at high temperatures, [battery] reactions happen faster and its protective structure can degrade."
Most EVs, however, are built with heating and cooling systems to regulate their temperature. Tesla, in particular, "controls these effects very tightly and often does not make them obvious to the driver, i.e. the dashboard range often does not reflect temperature effects," Recurrent says.
Why Does Cold Weather Reduce Electric Car Range?
Electric vehicles are powered by packs made of lithium-ion (Li-ion) battery cells. Li-ion batteries contain an anode, a cathode, and a liquid catalyst through which charged atoms move. When an EV’s battery becomes extremely cold, the electrolyte liquid catalyst inside becomes thicker and more viscous. That viscosity slows down the chemical reactions that channel electrons through the battery and power the car. It also affects how quickly the battery charges and limits the effectiveness of regenerative braking.
Cold temperatures also mean running the cabin heater. That plus other electronics—like the infotainment system—drain the car’s battery. The more they run, the quicker the charge depletes. Long stretches of highway driving also tend to sap the battery faster than city driving no matter the climate, but especially in cold weather. Taken together, these cold weather factors reduce range by up to 41%, according to AAA.
Still, "this range loss is temporary and there is no long term detriment to your battery," Recurrent notes. "As the ice melts and the temperatures rise, your vehicle’s expected range at full charge should return to normal." EV models also react differently to temperature dips, as this graph demonstrates, so your Tesla Model 3 may handle a Minnesota winter differently than a BMW i3.
Advancements in battery tech may ease at least some of the range lost to cold weather. We could see solid-state batteries that don’t require a liquid component within the next few years, which would eliminate the problem of the catalyst becoming viscous and slowing the reaction.
How Does Heat Impact Electric Vehicles?
With Li-ion batteries, excessive heat can be harmful. Heat accelerates the normal chemical reactions inside the battery and can degrade it faster than regular aging and use would. Too much heat can generate gas that may expand and crack the battery’s casing. In extreme situations, a battery can catch fire or explode, though EV batteries use liquid coolant systems to keep their battery packs from becoming too hot. So while it may not be an immediate problem (your EV won’t explode after one hot day), it’s still smart to take whatever measures you can to mitigate the effects of extreme heat on your car’s battery.
How to Prevent Weather-Related EV Battery Damage
Onboard battery management systems come standard with many electric cars and monitor the temperature and health of the power source. These systems will automatically activate built-in cooling or heating systems to keep temperatures stable. But there are a few ways to keep your battery in good working order.
- Top up throughout the day whenever possible—say, if you’re parked near a store with available charging infrastructure. A good rule is to keep the battery somewhere between 20% and 80% at all times. This is especially important in cold weather, when fast charging gets throttled to protect the battery.
- In hot weather, find shady places to park, such as under a tree or in a well-ventilated garage. When charging, give the car a few minutes to cool down before plugging in, or use a less powerful charger.
- In cold weather, warm up the cabin and the battery before driving off.
- Know how your range will be impacted before extreme weather hits. Look at the manufacturer range and resources like the Electric Vehicle Database to get an idea of what your mileage should be, then factor in some level of battery loss as you plan your route.
That said, most EV drivers won't find themselves stranded, even when their range is reduced by cold or hot weather. As long as you plan ahead, take measures to keep the battery at a good temperature, and know where nearby charging stations are, you’ll get from A to B in an electric car with no trouble.