Many electric vehicle (EV) owners notice the same frustrating problem during winter: their car’s battery seems to drain faster, and charging takes longer than usual.
When temperatures drop to around −20°C, these effects can become especially noticeable. But the reason is not just because drivers are using the heater more often.
The cold itself has a powerful effect on how batteries work.
According to battery expert Fride Vullum-Bruer, cold temperatures slow down the chemical reactions inside lithium-ion batteries.
These reactions are essential for producing electricity. Inside a battery, lithium ions move back and forth between two parts called the anode and the cathode.
This movement allows the battery to release energy that powers the car.
The ions travel through a liquid called an electrolyte. When temperatures drop, this liquid becomes thicker and more sluggish, almost like honey.
In very cold conditions, it can even begin to solidify. When this happens, the lithium ions move more slowly, which makes it harder for the battery to deliver energy efficiently.
Cold temperatures also affect the battery’s voltage. In freezing weather, the voltage can drop faster than usual.
Once it reaches a certain safety limit, known as the cut-off voltage, the battery automatically stops delivering power to protect itself from damage. This can happen even when some energy still remains in the battery.
Because of these factors, electric cars often lose a significant portion of their driving range in winter. In very cold conditions, such as around −20°C, a battery may lose between 20% and 50% of its normal range.
Many drivers assume that using the cabin heater is the main reason for the reduced range. Heating does use energy, but its impact is usually smaller than people expect. For example, preheating the cabin in a modern electric car typically uses around 0.5 to 1.5 kilowatt-hours of energy. Maintaining warmth while driving may use about 1 to 2 kilowatt-hours per hour. In comparison, the cold itself has a much larger effect on the battery’s efficiency.
There are several simple ways EV drivers can reduce the impact of winter on their batteries. One helpful strategy is to preheat the car while it is still connected to the charger. This allows the battery and cabin to warm up using electricity from the grid instead of draining the battery.
Charging the battery when it is already warm can also help. For example, it is often better to charge the car right after a trip instead of waiting until the next morning when the battery has cooled down. Charging an ice-cold battery can take much longer because the battery first needs to warm itself.
Drivers are also advised not to charge their battery to 100% on a regular basis. Stopping around 80% or 90% helps extend the battery’s lifespan. For even better long-term health, experts say batteries perform best when they operate between about 20% and 80%.
In extremely cold weather, it can also help to use seat and steering wheel heaters instead of heating the entire cabin. These features use far less energy. Avoiding many short trips in freezing temperatures can also reduce stress on the battery.
Looking ahead, researchers are working on new battery technologies that may perform better in cold conditions. One promising option is solid-state batteries, which replace the liquid electrolyte with a solid material. Several companies are developing these batteries, and some expect early versions to reach the market within the next few years.
Until then, understanding how cold weather affects batteries can help electric vehicle owners drive more efficiently and protect their batteries during the winter months.
