New technologies are always the target of abuse just like the new kid in a high school. When the fed managed to set a few EVs on fire, this got enormous coverage which ignored the fact that, in one case a seriously damaged vehicle was stored in an unsafe fashion and in another the gasoline vehicle parked beside the EV caught fire taking the EV with it. This piqued my curiousity. Fortunately, there are pretty good publicly available stats to look at. Even though there aren't that many EVs around, the proportion of EVs catching fire proves to be trivial relative to the proportion of gasoline powered cars catching fire while the occurence of spontaneous combustion of gasoline powered cars is astronomically higher than for EVs. Not only that, the stat for vehicle fires causing death is similarly skewed - an ordinary IC vehicle is much more likely to fry its occupants than an EV (on a per vehicle basis). And yet, which one gets the press coverage? This is the classic irrational fear of new things which the press likes to play up. At one time they put out a broadly repeated story that automobiles were dangerous because driving at more than 17 mph could be harmfull. They haven't done a good gasoline fired story since the days of the Firenza.
It's interesting that in the article there is a reference that a similar amount of energy in the form of gasoline being a bigger fire hazard. I guess that big tank of jet fuel contained in the same plane, that DIDN't catch fire BTW, is proof only that anything touched by the Green Groupies will be politicized until nothing is left in the conversation but hyperbole.
The fact is, this article (a good one) has a title that's more ironic than probably intended. Boing's problems ARE an indictment of Electric Car's use of LiIon technology. If Boing cannot get it right, with the massive safety critical emphasis placed on passenger plane design, how could ANY car company (with the emphasis on minimizing both NRE and recurring cost) be expected to get it right?
Hyperbole aside, Boing's cluster will hopefully help make electric cars and hybrids safer by the lesson's learned (when they are learned, I'll hold off judgment until then). It certainly points out the non-trivial nature of advanced battery technology.
My Hybrid uses NiMH technology, not perfect but acceptably safe. Is it's energy density really lower than LiION after you take into account the additional weight of the necessary cooling?
The reason for the fires is still somewhat of a mystery at this point, Rich. But your comment about not being conservative enough in their battery protection is probably right. The experts I've talked to have said that -- whatever the reasons for the incidents -- active cooling would have mitigated some of the risk.
I like this article very much. But in aviation the risk should be precise evaluated and allways minimized (the cost underlinks risk). Li-Ion will remain the most interesting electrical energy storage solution until the large TFBs will come ...2030???
This debarcle reminds me of event's in other industrys, Fix Or Repair Daily fitted a 'new' (to them) diesel engine to an existing product, Perkin's gave them the thermal load data and specified the minimum radiator needed, Fix Or Repair Daily's designers however went with a too small rad. resulting in cooked engines with cracked cylinder heads. Perkins after a short while of replacing engine's at their cost refused to supply anymore unless the rad. was upsized, Fix Or Repair Daily refused to do so and sourced an engine from another supplier, this one being less powerful needed less cooling, but Fix Or Repair Daily's designers fitted a huge cross-flow rad. more than twice the size needed, IF they'd used that with the Perkin's unit's it would have been fine, but the 'loss of face' admitting they were wrong was not acceptable.
Fix Or Repair Daily also had a series of trucks a few years later which were involved in several fatal 'accidents', each time the rear wheels had locked up under braking whilst unloaded slewing the truck sideways into oncoming traffic or pedestrian walkways. The fault was simply the designer deciding that a load/unload valve to compensate for load weight and grip level changes wasn't required. A practical braking systems engineer contracted to solve the issue tried various tricks, including graphite loading the brake shoes, but every time the rears locked up without warning, he fitted a load valve from a larger truck in the same range and it cured the problem. Fix Or Repair Daily's answer to his report was to tel him he was wrong and to fit smaller rear brakes, which whilst fine unloaded were not upto the job when loaded!
I suspect Boeing's designers had access to the huge knowlege pool on L-ion tech, but for space/cost reasons, and factors I will not speculate upon publicly, went with the smallest package possible, living in hope they'd get away without the cooling others, such as auto industry designers, know will be required. Long term if they don't admit their error those with a tech background will refuse to fly in a Boeing, the public perception of other L-ion use will still be tarnished, poor design choice shouldn't be an option, design by accountants needs to be stopped when it involves 'mission and safety critical' systems.
Perhaps asking accountants about reputational damage and limitation of risk needs to be part of their, and designers, training?
The question of whether engineers could have foreseen the shortcut maintenance procedures that led to the crash of American Airlines Flight 191 in 1979 will probably linger for as long as there is an engineering profession.
More than 35 years later, the post-mortem on one of the country’s worst engineering disasters appears to be simple. A contractor asked for a change in an original design. The change was approved by engineers, later resulting in a mammoth structural collapse that killed 114 people and injured 216 more.
If you’re an embedded systems engineer whose analog capabilities are getting a little bit rusty, then you’ll want to take note of an upcoming Design News Continuing Education Center class, “Analog Design for the Digital World,” running Monday, Nov. 17 through Friday, Nov. 21.
Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.