Updated: May 15, 2020
In this post, we'll see that in reality manufacturers are making the same mistakes that have been made for over a century, over and over. BUT WHAT MISTAKES, AND WHY? Are there design errors? Is it poor quality in manufacturing? Or is there something deeper?
Vehicle fires have always made the news. Watching the news media today, you’d be forgiven for thinking that this is a new problem that has arrived with electric vehicles, that they are more prone to such thermal events as they are referred to by lawyers and the politically correct. Journalists, of course, prefer the word fire; even better if they get to say deaths in the same sentence. Sensationalist tendencies and political positions result in a range of editorial viewpoints, none of them encouraging adoption of the technology: The most generous say that manufacturers need to build up more experience, the worst suggest that electric vehicles represent an inherently dangerous technology. Established vehicle manufacturers take the opportunity to have a pop at newbies, so you hear soundbites like ‘not so easy making a car, is it’? But looking at a sample of incidents around the world that were frequent enough to prompt governmental inquiry, it can be seen that the old guard aren’t any better. They were just slower in developing their offerings to the marketplace, but if slow was because they were being more careful, that doesn’t appear to equate to less incidents. It doesn’t look as if experience is worth much.
It seems like there are a lot of questions being asked about the safety of electric vehicles. But my experience and exposure to real problems suggests that there are a very small number of underlying causal mechanisms, many shared with (seemingly forgotten) similar incidents on internal combustion engine vehicles. Those that are unique to battery powered vehicles are shared with manufacturing problems that have also been around for at least a century too.
If this is the case, why do the same mistakes get repeated over and over? Why aren't the lessons being learned? Actually, it isn’t the case that design or manufacturing errors are at the root of the problem, it is the failure to detect them in time. Often this is excused when a fault is very rare, or intermittent, or both. Only once millions of a product have been in the field for months do these weaknesses manifest as catastrophes. Infrequent events are also regarded as special cases, but our experience is that they are not special at all.
It isn't the case that design or manufacturing errors are at the root of the problem, it is the failure to detect them in time.
The following hall of shame list shows such a sample of electric vehicle ‘thermal events’ over the last 10 years that prompted serious (usually governmental) investigations starting on the date shown:
Zotye M300 EV Apr 2011: short between battery cells and aluminum container
Chevrolet Volt Jun 2011: battery coolant leak
Fisker Karma Dec 2011: coolant leak at hose clamp
BYD e6 May 2012: short-circuiting of high voltage lines in distribution box
Dodge Ram 1500 Plug-in Hybrid Sep 2012: Thermal Runaway
Toyota Prius Plug-in Hybrid Oct 2012: saltwater ingress
Mitsubishi i-MiEV and Outlander P-HEV Mar 2013: Thermal Runaway
Nissan Leaf Sep 2015: Unresolved
VW e-Golf Dec 2017: Unresolved
Porsche Panamera E-Hybrid Mar 2018: Unresolved
Hyundai Kona Electric Jul 2019: Unresolved
BMW i8 Mar 2019: Unresolved
Tesla Model S and X Oct 2019: NHTSA open investigation into battery fires not related to collision or impact damage to the pack
Porsche Taycan Feb 2020: Unresolved
The list is certainly incomplete, and is purely based upon what one can find spending an hour searching in the public domain. I cannot verify it all as fact, but enough of it is verifiable that we should be able to see and trust any patterns emerging. One thing that jumps out straight away is that it appears to take years to undertake each investigation, and so for those cases after 2016, as far as the public is concerned, they remain unresolved.
Just as an aside, I am interested in currently hot scientific topics like epidemiology and climatology, and I do read background material on them. The topics are interesting, and it can also be useful to read good explanations supported by good evidence, and compare them with bad examples in order to hone my own skills. My opinions on these topics have developed as a result, but I would never dream of offering advice on problems related to them. That’s because I don’t have direct experience, and I haven’t read enough about the experiences of others. However, I was chuffed to hear this year about a classmate of mine from school who has had an Antarctic glacier named after him; the Larter Glacier.
On the other hand, reliability of manufactured products happens to be the one topic I do know a lot about. More than three quarters of my working life has been spent finding causal explanations for a combination of defective products at what is usually referred to as t=zero and also at t=n (after some period of time in the hands of customers). A fair smattering of problems I’ve seen over the last 30 years resulted in vehicle ‘thermal events’. And guess what? Years ago, the same set of causal mechanisms identified in the above list were also at play on non-electric vehicles. So, for those investigations not yet completed, I am prepared to wager my life’s savings that we will eventually see the same thing.