The saga of lithium batteries and the Boeing 787
LoopyByteloose
Posts: 12,537
Boeing has grounded all the Dreamliners due to lithium battery fires 'that never should have occurred'.
This is a very interesting situation. One might say a Titanic moment. I am not entirely sure which Lithium chemistry they went with and I doubt we will ever know the specific details of manufacture, but Lithium Ion batteries can and do out gas Hydrofluoric Acid in some instances of failure. And that will damage just about any material -- including epoxy and carbon fiber. After all, it is commonly used to etch glass.
This may be a defining moment in the use of Lithium Ion cells. NiMH have been showing a lot of promise and reaching power storage densities nearly the same as Lithium on a weight basic. So it is going to be very interesting if Boeing stays with Lithium technology or suddenly switches. Apparently, the Tesla uses NiMH batteries and they may know something that Boeing overlooked.
This is a very interesting situation. One might say a Titanic moment. I am not entirely sure which Lithium chemistry they went with and I doubt we will ever know the specific details of manufacture, but Lithium Ion batteries can and do out gas Hydrofluoric Acid in some instances of failure. And that will damage just about any material -- including epoxy and carbon fiber. After all, it is commonly used to etch glass.
This may be a defining moment in the use of Lithium Ion cells. NiMH have been showing a lot of promise and reaching power storage densities nearly the same as Lithium on a weight basic. So it is going to be very interesting if Boeing stays with Lithium technology or suddenly switches. Apparently, the Tesla uses NiMH batteries and they may know something that Boeing overlooked.
Comments
Jeff
This has everything to do with ignoring there own process for the sake of ridiculous schedules and short term profit on paper.
When Boeing said " the 747 shows we know how to do this" was the first mistake. When they said "we can save money be getting rid of the permanent engineers and have only contractors" was the second. When they said "Get it done by x date" was the final mistake. When you tell a contractor he's done on Friday, he goes away and its not his problem anymore. There's no one that can "own" any issue. When one tells a subcontractor "get six months of work done in three, or you will be the long pole in the tent" and be blamed (and penalized) for schedule slip, the sub-contractors play "schedule roulette". It looks good on paper, but we see the result: Improper bolts that won't hold thee wings on, landing gear that won't operate, fires in the cockpit. And schedule slip, expensive rescheduling of certification, expensive redoing all the work that was rushed through the first time.
I will not let any friends or family fly on the 787. But Boeing "knows what they are doing" so we have to let them do it. Hopefully the certification process will prevent the worst.
Sad, but true. Funny how there is never enough time or money to do it right the first time but always enough to fix the resulting problems afterwards. Usually costs a lot more to fix the problems later than it would have cost to do it right as well.
Yea, Someone should have told MS this about Vista!!!!
You're kidding, right???? I watched a program on How They Do It a couple months ago. They were showing how they make the the batteries at a facility in Nevada. Quite a cool process. The thinner they can get the material, the more power they can pack in a cell and they can be formed in pretty much any fashion. There is no way you would be able to accomplish that with lead acid and considering the power consumption the weight alone would kill the whole concept.
I suspect that Yuasa merely contracted the batteries to a sub-contractor that produces OEM lithium batteries. Lead acid batteries would likely be 4x the weight, and not recharge anywhere near as fast.
The core issue is that these batteries are supposed to provide emergency power as Boeing finally changed over from hydraulic controls to all electric in the 787. If they have to abandon that scheme, they need to build another airplane.
If I recall the only Pure mass scale EVs with NiMh was the S10 fleet that GM had with huges and the Rav4 EV .
While I agree NiMH is a mature chem for mid Line EVs and hybrids ..( for the money its a good value ! ) ... Its not going to power a car 300 Miles to a charge .
as far as the 787 /// Its boeing . Go figure .
I have more faith in the STS discovery then in a airliner ..
Still, we may just see a sudden huge shift in battery technology if the Boeing dumps lithium.
But lithium batteries? Looks like it might be a thermal runaway problem http://www.japantimes.co.jp/news/2013/01/25/business/dreamliners-battery-woes-traced-to-short-circuiting-thermal-runaway/#.UQOvcfLaiSo
and lithium batteries do seem prone to that http://en.wikipedia.org/wiki/Thermal_runaway
Replace them all with lead batteries I say, and offset the weight by not selling Krispy Kreme donuts at airports *grin*.
Dumping lithium batteries as a result of this issue would be similar to dumping the use of bolts after the tail problem.
The issue is entirely centered on pushing for arbitrary schedule deadlines in contradiction of the requirements and testing process. We can't guarantee 100% perfection, but we can show that we took care of the obvious blunders. When we hurry, the line between too much and not enough gets pushed the wrong way, and we trip over blunders.
Product development is prone to huge discoveries. In this case, it is all about chemistry and energy densities.
Along with huge increases that the energy density of lithium, we have seen instabilities which include chemical fires.
Meanwhile, I don't think that Nickle batteries have actually had fires. So, my gut feeling is that changing to different chemical elements may really be necessary.
You have to realize that while cell phone batteries may have been made relatively safe and even laptop computers, these batteries have been scaled up to provide enough power to actually fly the airplane. And in this case the airplane weighs much more than the average wood house in the US.
In other words there is a lot of energy stored in these batteries. Bolts don't store energy. It is a different degree of hazard.
According to my source at Boeing (flight test), the batteries did not actually catch fire. After inspection it was found that the lithium batteries had expanded. I wasn't paying real close to the discussion because my attention was divided but I can get more details tomorrow if you like.
-Mike
did Boeing think they could. As pmrobert pointed out,
This being a known issue should have raised red flags from the begining. They "supposedly" had backups in place in case of failure. That failed and makes me wonder was it really ever tested seeings how they were losing millions by missing delivery dates.
But if you bother to read that story it's likely just a short-circuit: "It reportedly was not plugged in at the time of the fire and the Karmas battery remains intact."
Any car can catch fire from faulty wiring. Ditto any plane. I think the real issue is that they are using an inherently unsafe battery chemistry in a plane - NiMH should
be used (and will likely be substituted to fix the issue). If using a lithium chemistry the only remotely acceptable one is LiFePO4 which will tolerate severe overheating
since phosphorous will not give up its oxygen to lithium anything like as easily as other electrode chemistries do. Saving a few 10's of kg of battery weight in
a plane that weighs 115 tonnes empty by switching to a pyrotechnic battery chemistry was plane stupid (spelling intended!)
Having seen the doco about the flawed 737 NG construction processes (Documented to have started with the construction of the 737-600's in 1996), and am familiar with corporate tactics of excessive contracting out of jobs, it really does look like it's now typical Boeing behaviour to take short-cuts (And have no problems never admitting it).
Here's a good example of just how flimsy the 737 NG load bearing structures are:
The collision was the two left wings collided, slicing the top half of the Legacy 600's winglet clean off. It's unlikely there was much more than a deep gouge with possible electrical and hydraulic damage in the 737's wing but that's just speculation on my part.
Where it says "inflight breakup" I interpret that as the main body broke in to pieces in mid-air! Which is the expected behaviour because of the poor construction. So, unless the 737 started cart-wheeling in mid-flight there is no good reason for it other than it's weak construction.
And that's just one of many such examples of sudden unbelievable breakups. There was one about two years back that actually saved lives because the 737 was on it's way to driving over a cliff off the end of a runway, but the roughness of the ground broke it's back before getting there. Freaky stuff.
Mark_T gave best selection of battery tech, NiMH or Lithium Phosphate. If the 787's aren't using one of those then Boeing have screwed up. And given the restrictions on carrying lithium on aircraft (For good reason) you'd think designers would err on the side of caution and go NiMH.
Not bad for a supposedly shoddy piece of design and construction.
The earlier, non-NG, models are fine. The faulty manufacturing started only with the NG models (-600 and after) as it was a redesign. The design was fine but implementation does not met the design specs.
Here's a link - http://www.futuregringo.com/2011/04/05/al-jazeera-boeing-737-documentary/ and the YouTube vid - http://www.youtube.com/watch?v=IaWdEtANi-0
Reading that it looks like something may have been done in 2004 to improve the production problems but there is a large number of 737 NG's out there that are just begging to fall apart.
But I still ponder my flight to San Francisco via Manila in 1996 where all the passengers had to line up 3 hours ahead of departure and have every carry on item inspected in detail for a mysterious 75cc of liquid. I now know that they were looking for nitro-glycerine. And this was due to an Al Quida incident that did down a Philippine Airlines plane that was flying to Japan.
I was just trying to save money by booking the cheapest flight to the US. Next time you tell you travel agent you want the cheapest flight available you might consider that others know something you don't.
I fear the government just 'doesn't want to panic people'. I am a bit wary of 'perfectly safe' or 'prefectly legal'.
One also expects companies to play fair with the consumer, and for regulators to do their job when companies screw up.
It's an engineering issue. There are LOTs of example of these batteries that don't catch fire, just as there are lots of examples of passenger vehicles that carry around highly flammable fuel and DON'T explode like burning Corvairs. We either design for the application correctly, or we don't. Its not the battery's fault that adequate engineering was done or not.
No, Boeing want profits. Individual people may or may not want other things, but these are secondary. Worry about anyone and anything that is more concerned with short term profits over long term stability.
reminded of a scene on an airplane (ironic yes?) from Fight Club
Narrator: A new car built by my company leaves somewhere traveling at 60 mph. The rear differential locks up. The car crashes and burns with everyone trapped inside. Now, should we initiate a recall? Take the number of vehicles in the field, A, multiply by the probable rate of failure, B, multiply by the average out-of-court settlement, C. A times B times C equals X. If X is less than the cost of a recall, we don't do one.
Business woman on plane: Are there a lot of these kinds of accidents?
Narrator: You wouldn't believe.
Business woman on plane: Which car company do you work for?
Narrator: A major one.
I would further like to add that it could be software, or it could be poor assembly (bad crimp connection), or poor overall design (mechanical or thermal).
Who knows what the design target was.
Probably something like:
Needs to be X by Y by Z and weigh less than N Pounds and provide W watts.
Failure to deliver by time T, this will terminate contract with penalty.
The sad part about this, is that with new design, you really can't define all of the parameters upfront.
Maybe the volume allotted for it for the watts required is impossible to make safely (or physically not possible).
Plus if you see my spec there is no talk about where it will be installed or any sort of reliability measurement.
(usually just assumed to be "must work forever without problems" but also the contradictory "make it cheap and easily replacable!").
What if "will be enclosed in a confined space insulated on 5 sides, next to a significant heat source" was left out of the spec, and the temperature tests were all performed at 120F ambient temperature max? What if it was installed next to a motor that vibrates severely? What if cables were stressed and damaged at installation? (my pet peeve).
Who knows what's really going on? and who is going to take back their assumptions that it was totally this or that when the actual cause was determined?
I know people have a right to be angry because lives were on the line, but I hate it when lay-people (not necessarily here) play engineer and say it must be this or that and this or that would make it not happen.