With more and more EVs being put on the road, the number of accidents involving such vehicles will increase. While they look similar to vehicles with combustion engines, they are a bit different underneath with the different powertrains and also the battery pack which adds significant weight.
As such, carmakers have also to give additional attention to the way EVs behave in accidents, and how well the occupants will be protected. In virtually all countries, vehicles have to meet certain safety standards and the manufacturers usually meet these standards or exceed them to provide an extra measure of safety.
Real-world crash scenarios
Mercedes-Benz, as a pioneer in automobile safety, obviously has done much to ensure that its EVs are as safe as its models with combustion engines. It has its own crash test facilities to see how the vehicle perform in actual crashes, supplementing computer simulations. The testing is usually secret since it involves prototypes of models not yet launched.
Recently, however, the carmaker was willing to make public a crash test involving two of its EVs – the EQA and EQS SUV – to show that it is going beyond not only the legal requirements but also those of the ratings industry. The crash test was conducted at the Group’s Technology Centre for Vehicle Safety in Sindelfingen, Germany.
Tougher than Euro NCAP test
The safety philosophy of Mercedes-Benz required its vehicles to not only pass defined crash test scenarios but also real-life accidents. In this respect, it referenced the Euro NCAP frontal impact test requirements which uses a 1,400 kg trolley with an aluminium honeycomb barrier replicating the front of another vehicle. In accordance with the specifications, the test vehicle and the trolley collide with an overlap and at a speed of 50 km/h.
Mercedes-Benz, however, made it tougher by using 2 real vehicles which are significantly heavier at approximately 2.2 and 3 tonnes, respectively. In addition, both models were propelled at a higher speed of 56 km/h, which meant that the overall crash energy was considerably higher than required by law.
The test scenario involving a speed of 56 km/h (35 mph) and 50 percent frontal overlap corresponds to a type of accident common on rural roads. The speed selected for the test takes into account that, in a real-life accident, the drivers would still try to brake before the worst case of a collision.
Deformed as programmed
Upon impact, the vehicles naturally deformed and to a viewer, the extensive deformation would seem alarming. However, just as Mercedes-Benz engineers long ago designed the crumpling bonnet and programme crumple zones to absorb the impact forces before they reach the occupants, the EVs have also been designed similarly.
Vehicle compatibility
Furthermore, the crash test clearly showed that compatibility (ie the interaction of the deformation structures of different vehicles involved in an accident) is part of the safety requirements for Mercedes-Benz vehicles.
As a result, the passenger safety cell of both vehicles remained intact and the doors could still be opened. In an emergency, this would be crucial, allowing the occupants to get out quickly or for rescuers to extract them.
Electricity cut-off
Where in vehicles with combustion engines, there is a fuel cut-off switch that triggers during a severe impact, an EV also has a cut-off function but for the high-voltage electrical system. This will ensure that the occupants and rescuers will be not harmed if there is any electrical leakage.
The EQA and the EQS SUV each carried two adult dummies (a total of three females and one male). Analysis of the up to 150 measuring points per dummy indicated a low risk of serious to fatal injury.
“Safety is part of Mercedes-Benz’s DNA and one of our core commitments to all road users. And to us, protecting human lives is not a question of drive system. The recent crash test involving two fully electric vehicles demonstrates this. It proves that all our vehicles have an equally high level of safety, no matter what technology drives them,” said Markus Schafer, Member of the Board of Management of Mercedes-Benz Group AG, Chief Technology Officer.