So far, comparatively little is known about the TÜV results for electric cars. Battery-powered vehicles have simply not been on the market for very long. In addition, their registration numbers are much lower than those of combustion engines. However, figures from the current TÜV report with two to three-year-old cars show that all-electric models from BMW and Tesla perform poorly in comparison.
The BMW i3, which made its debut in 2013, is particularly vulnerable with the low beam and the brake discs. With a failure rate of 5.9 percent, he ends up in the bottom third of the ranking. With the Tesla Model 3, 8.9 percent of the cars fail the first HU. Only four cars are ahead in this age group: including the Dacia Logan, Dacia Dokker and VW Sharan. What is noticeable about the Tesla - just like the BMW i3 - is a defective low beam and defects in the brake discs. The mid-range model from Elon Musk's company is also more susceptible than average to the fog lights and the axle suspension. Joachim Bühler, Managing Director of the TÜV Association, explains: "Because of the battery, many electric vehicles are heavier than comparable models with combustion engines. This often puts a special strain on the axle suspension."
The Renault Zoe, which is listed for the first time in the report due to its sufficient number of registrations and is exactly on average in the ranking with a failure rate of 5.3 percent, has the front axle suspension as its biggest defect. "In particular, wishbones and tie rods and coupling rods are conspicuous," it says. The function of the foot brake was also complained about above average in the small car.
According to Bühler, typical defects in electric vehicles also include defects in the brakes. One of the reasons for this is the recuperation that electric vehicles use to recover braking energy. Because the brakes are used less, their effectiveness decreases. Drivers of e-cars should therefore "brake hard regularly to regenerate the brake pads and thus maintain full braking performance," recommends the managing director of the TÜV association.
The Nissan Leaf comes up with a better result. With a rate of 4.3, the compact car has fewer defects than the average. However, there are also vulnerabilities here with the low beam and the brake discs. This places the Leaf in the top third of the ranking for two- to three-year-old vehicles.
During the main inspection of electric vehicles, the high-voltage battery, the electrical cables and, among other things, the attachment, insulation and cooling of the power storage are checked. However, the high-voltage batteries would only undergo a visual inspection. "That's not enough," says Bühler. The regulations for the main inspection would have to be supplemented by further specific test points for the safety of electric cars. "It must be possible to evaluate the high-voltage battery over the entire life cycle of the electric vehicle. To do this, the testing organizations need access to the data from the battery management system," demands the managing director of the TÜV association. In addition, the high-voltage safety of the electric vehicle would have to be checked in general.
According to the TÜV, the increasing encapsulation of the underbody in electric vehicles is also problematic because it means that the high-voltage cables and the brake lines are no longer visible. E-cars, on the other hand, have one plus point: According to the TÜV, even older e-cars are not particularly susceptible to rust.