Electric cars in the heat: protect the battery and guarantee range

• Challenges in the summer heat: high temperatures significantly weaken the performance and service life of electric car batteries. Overheating can lead to a decrease in charging speed. In extreme cases, the charging process can stop completely.
• Optimal charging technology: electric vehicles should be charged more slowly in summer and at shorter intervals. You should avoid using fast-charging functions.
• Air conditioning and energy consumption: pre-conditioning the vehicle during charging is a good idea to minimise energy consumption during the journey.
• Driving style: a consistent and anticipatory driving style conserves the battery. Avoid abrupt braking or accelerating to minimise energy consumption.
• Parking: opt for spots in the shade.

The prejudice that electric cars have a higher risk of fire than combustion engine cars is still widespread. In our article “Electric cars: does the battery pose an increased risk of fire?”, you can find out why heat isn’t a safety hazard for electric vehicles and what you can do if ever a fire does occur.

High summer temperatures can pose challenges for electric cars. In the following five points, we’ll show you how heat affects your electric car and what you can do to best protect it.

High temperatures are a problem for us – and the technology in your e-car too. This applies not least to the lithium-ion batteries in electric cars. They work best at a constant 15 to 25 degrees Celsius. If the battery reaches a temperature above 50 degrees, the electronics deteriorate faster and overall charging performance decreases.

The reason for this is the material the batteries are made from. Excessively high temperatures trigger a degradation reaction. Specifically, the electrolyte in the battery evaporates and is gradually and irreversibly damaged. As a result, the battery performance decreases. The good news: most modern electric cars have appropriate battery cooling technology. In addition, the batteries are usually located in the underbody of the vehicle, which protects them from direct sunlight.

The vast majority of charge management systems in modern electric cars automatically curb charging when the temperature of the battery rises noticeably. This is to prevent the battery from overheating. The following points should be taken into account when charging your electric car in the height of summer.

• Do not charge at full power: when outside temperatures are high, the charging rate should be decreased. This is often possible via an app.
• Less, but more often: only charge the battery up to around 80 % and plug the car in to charge a little more often. This helps to keep the heat of the battery generally low.
• Charge overnight: whenever possible, charge your electric car at night or early in the morning. This definitely saves money, as electricity prices are lower during these times. In summer, this makes all the more sense due to the lower temperatures at night.
• Use charging stations in an underground car park:  what goes for the car’s battery also applies to the charging stations, i.e. they’re also sensitive to heat. Those who are out and about and need to charge their car should therefore prioritise using stations located in underground car parks.

One of the main power guzzlers in any car – whether electric or petrol/diesel – is the air conditioning unit. In contrast to a combustion engine, however, an electric car has one huge advantage: The interior of the electric cars can be cooled down while the car is still at the charging station.

In this case, the air conditioning unit draws energy from the power grid and not from the car battery. So you can sit in a perfectly cooled car, meaning you’ll use less energyto then maintain the internal temperature.In most electric cars, pre-conditioning can be programmed either via the on-board computer or via an app.

Not only would your former driving instructor appreciate it if you could drive with as much foresight and serenity as possible, but your car battery will also thank you. Why? Abrupt braking and strong acceleration cause the battery to heat up. This in turn leads to more energy being used to cool the battery.

Whether in summer or winter, driving style is an essentialfactor in preserving the service life of a car battery,which you can read about in our article “Electric cars: battery recycling for better sustainability”. You can also find more tips for using electric cars in our video:

Although this is obvious advice that’s repeatedly recommended by car manufacturers, it’s still important to mention here again. It’s always a good idea to park in the shade. Sunlight in itself is not a risk factor, as the heat it produces isn’t enough to overheat a battery. However, the heat of the sun can still affect the range of the car.

When you park in the shade, the battery cools down more quickly and more intensely after use. Accordingly, less energy is then needed to cool it later – energy that helps you to cover those sometimes crucial extra kilometres.