Batteries under stress

There is a fire. Lights flash upwards, and black smoke is visible from afar above the fire. Right in the middle: the battery of an eTruck from MAN. Can it withstand the flames? Or will she start burning herself? Fortunately, the dramatic situation is not taking place in real road traffic, but on a test site. There, a team of MAN engineers is currently conducting a "Fuel Fire Test". The scenario: An MAN eTruck has collided with another vehicle, leaked fuel has ignited, and now the battery is in the middle of the flames.

"Even under such extreme conditions, there must be no danger from the battery," explains Christian Pastötter, team leader for battery validation at MAN. "The design must ensure that it does not start to burn itself." To check this, the team set the battery on a kind of grill and lit a fire under it. After a minute and a half at temperatures of 800 degrees, the battery is driven aside a little and remains exposed to great heat due to the proximity to the flames. In the end, she passed the test: Neither the direct flames nor the heat of the fire could set them on fire.

Bollard against battery

When crossing the bollard, a blow is simulated from below against the battery housing, as can occur when driving at 35 kilometres per hour over a bollard. "Here, the underbody seal must show that the battery remains intact – i.e. that no electrical fault occurs despite external damage, for example," says Pastötter. This verification also succeeds.

Also for the "Flying Part Test": A metal part is catapulted against the battery at 89 kilometres per hour, which must then continue to function. In reality, for example, a large piece of metal may have been whirled up by a vehicle in front and thrown against the MAN eTruck.

In addition to road traffic, logistics also presents some challenges for batteries. For example, you may fall from a forklift truck – a scenario that is investigated in the "Drop Test": From a height of one metre, the testers allow the battery to collide slightly at an angle on a concrete floor. She also masters this situation with flying colours. "All the stress tests have shown that our batteries are very robust," concludes Pastötter. "Many customers still have some respect for the new technology. But no one has to worry: MAN batteries are safe."