None of that matters. He/they would have to convince me that LiPo/LiIon packs are safe. This coming from someone who's waiting for Tesla's SUV's. I kind of draw a demarcation line between flight and road-based vehicles. Fires are a thousand times more dangerous at 30,000 feet.
The fundamental issue I keep coming back to is that Lithium Polymer batteries are dangerous. One or multiple cells. It does not matter.
I've been using and abusing them extensively for, I don't know, maybe a decade, in all of my RC gliders and helicopters. I keep them locked-up in a fireproof container and never --ever-- charge them unless I can be in the room during charging.
There are plenty of accounts in RC circles of battery packs spontaneously combusting, catching fire in flight, catching fire while charging or lighting-up if damaged. The problem, as it was explained to me, is that these cells can produce methane and have an avalanche failure mode. Methane is a product of a manufacturing defect whereby a small amount of moisture is sealed into the package. Lithium reacts unfavorably with moisture and the rest is history.
Lithium Polymer battery fires are extremely hot, fast and very powerful. I've seen it myself with three and six cell packs. I would not want to be anywhere near a fire in a larger pack.
And so the fundamental question for me is simple: Why? Why use Lithium-based chemistry for a flight battery pack. Yes, I know, lower weight, lower volume. However, I am not sure these packs can ever be considered to be safe. How can an aircraft manufacturer ensure that the quality of the packs it assembles is as required? Can you ever know?
I know millions of Lithium-based batteries are in use in everything from phones to laptops and more. Not sure how to think about that. A fire is a fire. A laptop stowed away in cargo can still cause a huge problem if it catches fire.
To be fair, I have never had a spontaneous fire in any of my thirty of forty packs (ranging from 2 cells to 12 cells). I have had cells spontaneously puff-up --inflating like a baloon-- and destroy the pack by expanding so much that the battery pack's casing cracks open. In those cases I've used them to experiment by overcharging to see how they light up. It does take a lot, but when they do it is massive fireball.
Perhaps someone with information closer to the source or quantifiable safety and reliability data can pitch in?
EDIT: Prior to LiPo's I was using NiCd (Nickel Cadmium) cells and have never had any issues, even with abuse and mechanical damage.
And more power density. I'm hoping an aeronautical engineer will eventually chime in, but this document is a pretty good technical read:
http://www.boeing.com/commercial/aeromagazine/articles/qtr_4...
Or this One:
http://gm-volt.com/2012/03/30/the-all-electric-boeing-787/
The major change was going to a "no-bleed" engine setup which allows for more efficiency. But it also means you need a much more powerful battery to start up the secondary power systems.
Boeing, by contrast, more or less attempted to introduce some... "buffering" into their extant design: (Additional) cell spacing -- as much as they could wedge in -- and maybe some other tweaks. Rather than really fixing the underlying problem.
I may be all wrong/wet, but that's the impression I was left with.
I think that if Boeing wants to salvage a good degree of near term profitability on this product line, they should begin talking to Musk. Actually, were it my call, even if the decision was to "fix" what they already had, I probably would have run a parallel examination and perhaps testing out of Musk's technology. Some millions on such an effort would be cheap "insurance", to bend that word -- no guarantee of a workable alternative, but a decent bet. And, even if you fix what you have, you now have a redundancy... and maybe you've learned something, along the way.
In short, Boeing needs to lop the top off a few internal egos, perhaps. Just speculation on my part, but...
The reason the 787 was grounded previously, was that Boeing and the FAA determined that the battery pack was insufficiently protected. The protection of the battery pack has been upgraded, both physically and electrically.
RC batteries and their charging systems are not nearly as thoroughly designed or protected as aircraft batteries.
Both of this aspects are supposedly against the Boeing as the development (and thus certification, etc..) was done many years ago, thus they are behind technologically (like any other system/technology in aviation which have direct consumer counterparts) and Boeing is being run by MBAs which means they would typically be trying to be cheap bastards ("bottom line").
You're wrong. Billions are in use. Billions of laptops, tablets, cell phones, smoke detectors, and other assorted gadgets are sold every year with these batteries. There are several within easy reach of my chair right now. I bet if I tracked down every lithium battery in my house, there would be at least a couple dozen accumulated over the years.
Just today, the New York Times said[1] "The Consumer Product Safety Commission has documented more than 350 fires involving lithium-ion batteries since March 2012".
350 fires out of the hundreds of millions of these batteries that must make their way into Americans' hands every year.
Perspective: In 2012, 28 Americans died from lightning strikes[2] (a below-average year, at that). In 2010, over 4,000 pedestrians died being in the US[3]. You don't want to know how many people died in 2011 to tornados.
I can't think of a single death that has been attributed to a lithium-ion battery fire, and only a handful of injuries.
If lithium batteries aren't safe, I don't know what is. Boeing has done something deeply wrong.
[1] http://www.nytimes.com/2013/06/13/business/lithium-ion-batte...
[2] http://www.nws.noaa.gov/om/hazstats/light12.pdf
[3] http://usatoday30.usatoday.com/money/autos/story/2012-08-02/...
By analogy: there are at least something 10^34 (10 million billion billion billion) uranium atoms on earth, and they weren't explosive for billions of years, yet somehow they seem to be potentially quite explosive since 1945.
It's a question of critical mass. A small lithium ion battery may be safe, a large one may not be. Just because there are billions of tiny lithium ion batteries on the world that are relatively harmless doesn't mean large ones aren't - the energy capacity rises in the cube of the size, but heat dissipation only quadratically.
In short, because it works safely in the small doesn't mean it's easy to implement safely at scale.
Can Lithium batteries fail? Yes. But keep in mind that flying along with you and the batteries is many tons of flammable fuel, wrapped in aluminum and carbon fiber, which are also flammable, with miles of high-powered electrical lines running through it all. And we know from TWA800 that those are enough, by themselves, to bring down an airliner.
But we also know that that happens very rarely, because engineers can mitigate dangers if they are aware of them.
> Unfortunately, the pack architecture supplied to Boeing is inherently unsafe. Large cells without enough space between them to isolate against the cell-to-cell thermal domino effect means it is simply a matter of time before there are more incidents of this nature.
http://seattletimes.com/html/businesstechnology/2021380327_7...
peeks from under tinfoil hat
