Another Tesla has crashed – and burned.
And, killed.
Two Florida teens lost their lives on May 9 when the Model S they were traveling in erupted into flames after striking a concrete barrier. As in previous incidents – at least three others – a large portion of the car was quickly and almost completely consumed before the fire was put out.
Since Teslas are electric cars and don’t burn gas, this one wasn’t burned to a cinder by gasoline.
It was the lithium-ion battery pack that caught fire.
This happens when the physical structure of the battery pack is compromised and the materials within come into uncontrolled contact. Just the same as exposing gasoline to an ignition source. It can happen as the result of a design defect, or an impact such as an accident.
What’s not the same is the way electric car battery packs are shaped – and where they’re installed in the car.
Which is everywhere.
Like most electric cars, the Tesla’s battery pack runs the length and width of the floorpan. This is necessary because electric car battery packs are very big – and very heavy. Spreading them out flat and wide puts all that weight lower to the ground and leaves room inside the car for passengers and cargo.
But the downside is that you’ve got a car that’s vulnerable to an impact-caused battery fire no matter where it’s hit. The infamously exploding Pintos of the ’70s caught fire when hit from behind. Because that’s where the gas tank – the weak point – was.
In an electric car like the Tesla, the “gas tank” is everywhere.
The danger can be reduced by designing the car to withstand impact forces which could damage the physical structure of the battery pack and trigger thermal runaway – the term for a lithium-ion battery fire. But it’s trickier, because a battery fire can be triggered by lesser things, including vibration/jostling as well as extremely minor defects imparted during the manufacturing process.
