26-04-2021 | | By Robin Mitchell
Recently, two men have died while putting the “auto-pilot” feature in their Tesla to the ultimate test. What exactly happened with the Tesla, why should engineers be careful with names and claims on products, and do Lithium-Ion batteries continue to present challenges for car safety?
Recently, two men in Texas took out their Tesla Model S to test out the auto-pilot features. Upon going around a bend at high speed, the vehicle skidded off approximately 100 feet before hitting a tree. The resulting crash damaged the car enough that the battery system failed to cause an intense fire, and according to the fire department, the fire (which would normally take minutes to put out), took over four hours to extinguish fully.
While the incident is still being investigated, authorities have concluded that during the crash there was nobody behind the wheel; one passenger was sitting in the front passenger side, and the other was in the back seats. Furthermore, the authorities have said that it was already investigating more than a dozen incidences of Tesla vehicles crashing with the auto-pilot feature being the main suspect of each case in the previous month.
Before we continue, it goes without saying that Tesla is not at fault with the two men's incident. Driving a car at high speed with no one at the wheel is an unbelievably dangerous act that put the lives of the passengers at risk and other drivers on the road.
However, there is an increasing trend of Tesla crashes resulting from customers utilising the “auto-pilot” features. This leads us to the question of how engineers name their designs or features, and if the naming of a feature can land an engineer at partial fault.
Currently, Tesla vehicles are level 2 autonomous vehicles meaning that the car can mostly drive itself on clear roads including steering control and acceleration. However, level 2 autonomous driving also CLEARLY states that a driver MUST be behind the wheel ready to take action should anything go wrong. However, it appears that this fact goes unnoticed by those who operate Tesla vehicles, and this may be a result of the name “Auto-Pilot”.
When engineers name features and designs, they should think carefully about how an average individual will interpret that name. For example, an IoT device could have a feature called “auto-protect”, giving the impression that it will handle all its own security. However, that device could still be vulnerable to basic passwords, commonly used login details, and insecure networks. Another example could be calling a device “fault-free”, but even then damage to the device or improper use could still pose a risk. In the case of Tesla, calling the self-driving feature “auto-pilot” is very counter-intuitive as the feature is far from a true auto-pilot.
Another area of concern from this incident is the dangers posed by lithium-ion battery technology. While the car clearly crashed due to poor judgment, the resulting fire from the vehicle took four hours and 30,000 gallons of water to put out.
When petrol burns, it is surprisingly easy to put out, and even then, petrol in a tank won’t explode (like in movies), because it requires a source of oxygen. Lithium-Ion batteries, however, are incredibly energy-dense, and the use of lithium presents multiple challenges.
The first problem with li-ion is that internal shorts between cells can be formed during a fault (such as a crash). This results in large amounts of current which cause the battery to heat up and approach its flashpoint. Secondly, a short circuit can result in hydrogen production, which causes the battery's internal pressure to increase.
This is because Li-ion batteries can explode releasing large quantities of hydrogen, which can then catch fire. The lithium in the battery is then exposed to oxygen while being heated far beyond its ignition temperature which results in a very dangerous fire.
But, pouring water on the fire can result in the production of more hydrogen as lithium reacts with water to produce lithium hydroxide and water. From there, not only is the battery on fire, but a strong corrosive solution is formed.
Engineers need to be careful when naming technology as many will take the name also to describe its function. Furthermore, makers of electric vehicles may need to consider alternative battery technologies as incidences such as this could sway regulators to bring in regulation against lithium-ion technologies.