Winter time is not battery time. Owners of older diesel cars are particularly aware of this. If a battered battery is still running respectably through the summer, it only lets the starter twitch exhausted when it is frosty. It is not for nothing that battery defects are still clearly at the forefront of the reasons why a car no longer starts. Low winter temperatures also hit electric cars and their comparatively huge lithium-ion energy dispensers.
It's less about the fact that they don't start anymore (that can happen too). Rather, they lose massively in available capacity and thus range. How strong, the a uto motor und sport explored with TÜV Süd in the world's first heat /cold test bench comparison test for electric cars. A separate test program and cycle was developed for this. So much in advance: The results give reason to shiver. But first back to theory. Why is the electric car losing range?
That is why the batteries of electric cars suffer in the cold
Two reasons are responsible for this: First, the electrolyte, i.e. the substance that is internally in a battery cell of an electric car for the power line between positive and Negative pole ensures. When it is cold, the electrolyte becomes thicker and the electrochemical processes run more slowly. This increases the so-called internal resistance of the battery, which now supplies less electricity and thus less power.
With simple lithium-ion batteries in an electric car, the electrolyte can even freeze below minus 20 degrees. Even though particularly cold-stable electrolytes still function below minus 50 degrees, the cell still loses available capacity. Active heating of the battery would help, but that costs performance again.
Heating as a range killer in electric cars
This brings us to the second point: In winter, electrical consumers suck a lot of electricity. If an electric interior heater thunders at low temperatures, it can quickly generate up to four kilowatts. With a 16 kilowatt-hour battery in an electric car, that would mean that theThe battery is vacuumed empty in four hours without the car moving a meter.
While in a car with a combustion engine the heating energy is hardly noticeable compared to the gigantic heat losses, it becomes the determining factor in electric cars. In addition, there is an increased power requirement of the lighting units in winter and - similar to a combustion car - higher frictional resistance. As the measurements show, all of this leads to sometimes blatant loss of range in electric cars.
Range of the E-Smart drops by 47 percent
They are particularly serious with the Smart Fortwo ED, which in the first test after the EU cycle at a cozy 23 degrees was a considerable 208 kilometers comes and thus even exceeds the factory specification by 73 kilometers. Even in the second test on the roll after the recuperation-friendly TÜV Süd electric car cycle, he still achieved more than promised at 159 kilometers. For an e-car that is mainly used in urban areas, values above 100 kilometers are pure luxury anyway, since the previous model tests clearly show that over 90 percent of trips take place well below this.
The Smart owner is happy and is planning a trip to his relatives 100 kilometers away for Christmas. There he wants to recharge again, but at kilometer 84 the flow of electrons suddenly stops. The E-Smart can barely manage that much at minus seven degrees Celsius according to the TÜV Süd cycle. This means that the range of the electric car drops by almost half compared to the test bench value at 23 degrees outside temperature and by over a third compared to the factory specification. It is simply worthless in winter. After all, the Smart - like the Mitsubishi i-MiEV, which has lost 43 percent (only 64 km) - heats the interior purely electrically to a comfortable level.
Mia Electric loses seven percent
In contrast, the electric three-seater Mia, which was tested in the prototype stage, simply switches off the electric heating. The losses in the cold in the TÜV Süd cycle remain very low at minus seven percent, but the little booth is also cold. However, the production version should heat like all the others. Then another 20 percent loss of range must be taken into account. Even if the Mia (in absolute terms) does very well for its small battery and completely sufficient for the city, its factory specification is also unusable in winter.
Fiat 500 Karabag dispenses with electric heating
The developers of the Fiat 500 Karabag therefore let themselvesThey didn't even switch to an electric heater, but gave their converted small car an additional gas heater. Although it also loses 20 percent due to the cold battery, with 105 kilometers it offers by far the greatest range security in the cold. The penalty is the additional costs and the 0.5 liter fuel consumption per hour. At least in winter it then loses its emission purity (no pollutant filtering). It's bearable, because the Karabag would heat up for up to 15 hours in a traffic jam without the remaining range having to suffer.
Comment by Alexander Bloch
No, you won't get one from me now read populist 'electric cars offer too little range'. On the contrary: some of the small electric vehicles have a larger one than is needed for a second car in the city. And battery capacity is expensive. Less is more, as the cheap Mia Electric proves. What auto motor und sport vehemently demands is range security. It cannot be that there are 144 kilometers in the prospectus of an electric car and only 64 in winter. With a new battery, mind you. Anyone who ends up on a city motorway in a wintry mega-jam not only does not come home, but it soon becomes really cold without electricity for the heating. Therefore, in addition to the factory range specification, under optimal conditions, reliable information must also be provided for the most difficult case. How to measure this was shown by auto motor und sport together with TÜV Süd. It is now up to the legislator to require such labeling to be mandatory in order to provide clear customer information. We'll check it out.