ICAO says no to lithium-ion batteries: The UN organization ICAO apparently will reverse itself and say that lithium-ion batteries should not be shipped as cargo on passenger airliners. This seems like a prudent move, considering the history of fires involving this battery type, even before the Boeing 787 incidents.
Dendrites and the 787: It sounds like something out of your biology class. Microscopic things called Dendrites might be the root cause of the lithium-ion battery fires on the 787, according to the first reporting from The Wall Street Journal. (Subscription required. Here is a Reuters story on the same topic.)
Deleting Flightblogger: Alas, we deleted Flightblogger from our bookmarks. Jon Ostrower created this blog and built it into a major aviation resource. When he departed Flight International for The Wall Street Journal, Flight half-heartedly (if that) continued the column, but there hasn’t been an entry since August.
Rolls-Royce Certifies Trent XWB: Rolls-Royce received certification for the Trent XWB, which will be used for the Airbus A350.
Airbus still ponders battery future: Airbus is still considering what to do about the plans to use the lithium-ion battery in the A350. A Seattle TV station reported Airbus made the decision to drop these batteries in favor of older, proven technology. Airbus told us this isn’t so (yet). Says a spokesman:
We are following the 787 investigation closely and will evaluate whether any recommendation applies to us.
We have a robust design. If this design has to evolve, we have the time to do that before first delivery.
Nothing prevents us from going back to a classical plan that we have been studying in parallel.
We have all options open, which we keep evaluating in pace with the ongoing investigation.
Someone remember “tin whiskers” an early bane in electronics.? ( we actually may see them again with lead free solder types )
“It sounds like something out of your biology class.”
You apparently did not the correct class as this is physical chemistry 🙂
And myself I missed the English one, it was suppose to read “You apparently did not attend the correct class as this is physical chemistry” 🙂
And myself I missed the English one, it was supposed to read “You apparently did not attend the correct class as this is physical chemistry” 🙂
…okay. But actually the term ‘dendrite’ originated with the anatomy of the neuron, so he’s recalling it correctly.
Dendrites (from Greek δένδρον déndron, “tree”)
The Reuters version at least (I haven’t read the WSJ) simply states it’s one of many possibilities. This is another non-story, I’m afraid. Dendrites, porous separation layers, electrode corrosion, local variation in electrolyte concentration, etc. are all “normal” things to find in an ageing battery (from what I recall of my university course on electro-chemical corrosion ).
The dendrite story is in conflict with the earlier story that Boeing has a “fix”. If the dendrites are the problem, there is no quick fix other than to change the battery type and in that case I doubt the 787 will be back in the air next month.
But my point was I don’t think it *is* a story… It sounds like someone from the press asked for possible causes for battery failure, someone started to list the usual suspects, the journalist pounced on a cool-sounding word they’d never head before and asked “tell me about these dendrites”, et voilà… new “scoop”.
hyperbole? ( can’t get at page content ):
Yes. Not true facts, anyway.
Thought so. Any idea what report ( official or not ) was referenced?
Apropos, CT Scan 3-D rendering for the ANA battery:
showing cell expansion and deformation.
Interesting- on the WSJ article re dendrites- a blogger mentioned that apollo fuel cells had a similar problem — the cure was after many hours to go out and give it a whack …
Maybe true- maybe not – but an interesting concept.
Pftt, so FAs will get to play a game of “whack a mole” in the eBays ;-?
Maybe replace Flightblogger by http://theplaneblog.wordpress.com/ or some other new ones
I still get the FG Flightblogger site under Jon Ostrower..
The rule that ICAO wants to reverse is actually a brand new rule that was put in place only a few weeks ago at the request of airlines. Presumably because of the very high rate of battery replacement on the 787. The idea being to facilitate transportation of 787 batteries in order to prevent any aircraft from being grounded for too long. It’s ironic isn’t it?
So, when did ?Boeing? start to lobby for this easement?
( article I had found a couple of days ago spoke of interest from “the battery industry” )
The fact that they’re still trying to diagnose the cause of the problem isn’t good news at all. You can’t have a fix if you don’t know what needs fixing.
Both Aviation Week (http://tinyurl.com/b5cdyqn) and Wired (bit.ly/14GvfBC) reported on dendrites being a problem last week. Nice to see Reuters and the WSJ catching up.
The WSJ article offers the best explanations on the subject of dendrites if someone (no pun intended) wants to know why “it’s a major element of the overall probe”.
The Wall Street Journal:
– “Dendrites are tiny deposits of lithium resembling microscopic whiskers that can grow within the cells of a battery, potentially causing short circuits and significant heat and even fire.”
– “They are often a byproduct of rapid or uneven charging of lithium-ion batteries.”
– “Top NTSB spokeswoman Kelly Nantel said investigators are “looking at whether dendrites may have been a factor in the short-circuits” that led to the Jan. 7 battery fire.”
– “She stopped short of saying investigators have concluded that the structures were the primary cause of the sequence of events that led to the Japan Airlines lithium-ion battery rupturing and burning. But her comment suggests that safety board experts are now delving into the issue as a major element of their overall probe.”
– “At the time, Ms. Hersman also said investigators were casting a wide net looking for the cause of the short-circuits, including how individual cells were charged, the physical separation of the cells and their electrical interconnections. Dendrites were not explicitly mentioned.”
– “It takes time for the dendrites to grow and [the plane] can have several flights, and everything’s going fine and suddenly” there’s a fire.”
– “The critical factor is charging too fast on some cells.”
– “Chief engineer Mike Sinnett said last month the company chose lithium-ion “because it has the right chemistry” to discharge a large amount of power to start the auxiliary power unit in the tail of the jet or even its engines.”
Even it’s engines? That’s the part I don’t understand. The battery is not powerful enough to start the engines, even if these have starter generators. But it can start the APU, which is a much smaller jet engine.
To place the excerpts in their original context please read the entire article:
…The 787 is the first passenger jet to rely heavily on lithium-ion batteries. Boeing 787 chief engineer Mike Sinnett said last month the company chose lithium-ion “because it has the right chemistry” to discharge a large amount of power to start the auxiliary power unit in the tail of the jet or even its engines “and then allow us to recharge that battery in a relatively short period of time.”..
One would think as Chief engineer he knows what he is talking about. Possibly in some sort of emergency – but I doubt it !
Of course, this is the same guy who told SPEEA that he(Boeing) had lots of qualified Engineers in Calif and other places who could replace the SPEEA types, including the DER’s
which is absolutely untrue…
Also a refugee from MDC and Military
Seattle – Boeing – YOU HAVE A PROBLEM
OOOpsie – my bad I confused Delaney with Sinnett – here is the stackup announced in 2010 from the boeing site
The newly appointed leaders and their technical areas of responsibility are:
Boeing Commercial Airplanes
Mike Delaney — Airplane Performance & Product Architecture. Delaney was vice president, chief project engineer for the 787 program.
Keith Leverkuhn — Propulsion Systems. Leverkuhn was vice present/general manager of Propulsion Systems for Boeing Commercial Airplanes.
Jim Ogonowski — Airplane Structures. Ogonowski was director, chief structures engineer for the 787 program.
Mike Sinnett — Airplane Systems. Sinnett was vice president, systems chief engineer for the 787 program.
As part of their new assignments, Delaney, Ogonowski and Sinnett will continue to focus on the 787 program, which is currently the most important engineering challenge for Boeing Commercial Airplanes.
Delaney is from MDC
Sinnett is not !
It has the chemistry to suply the sort of power pulse required to start jet engines. The final battery design may be too small, but it can be scaled.
Of course this is true of all battery designs – they can all suplpy whatever power you need, but at different mass/volume penalties.
A process for getting rid of dendrites during battery charging was invented over 50 years ago. It is a combination of electropolishing combined with ordinary charging. See http://scripturalphysics.org/qm/adven.html#ChargingWith_AC/DC_waveform
“Process and apparatus for renewing exhausted primary, more particularly dry, electric cells or batteries,” Ernst Beer, June 26, 1956. ( http://www.freepatentsonline.com/2752550.pdf )
Some interest by NASA (http://pages.ripco.net/~marnow/uk/NASA_Vargo_Start.html) :
“. . . it is well known in the plating field that periodic current reversal methods can plate coatings at a much faster rate than can be done by conventional direct current methods. It is further known that the reverse-current part of the charging cycle will tend to act as a depolarizer. Use of this technique should lead to significantly higher battery-charging rates. Furthermore, a problem with dc chargers is that the electrode material is plated on as a loose, spongy mass which often falls off and ultimately leads to battery failure. The current characteristic of this battery charger is similar to that used in electropolishing circuits and because of this characteristic, electrode material should be replated as a smooth, hard surface (ref. 1), thereby contributing to increased reliability and long life.” (Brief Investigation of an Asymmetrical Alternating-Current Battery-Charging Technique by Donald J. Vargo)
From the original patent, http://www.freepatentsonline.com/2752550.pdf :
” . . . a current is passed through the cells or batteries to be treated, consisting partly of alternating current and the remainder of direct or pulsating direct current. For charging or renewing normal commercial cells or batteries, the treating circuit can therefore include a rectifier with a very considerable leak (50-90%) or a rectifier bridged by a resistance. . . . Experiments with dry hearing aid batteries and pocket lamp batteries have shown, that by a treatment according to the invention the life of such batteries can be lengthened to 20 to 30 times the normal life.”
The process was originally intended for primary batteries, which were not intended to be recharged. This technology comes from the 1950s and can easily be done today, even by hobbyists (or as a science fair project). Wouldn’t you like to have rechargeable batteries that last 20-30 times normal? Do you think that there would be a market for such a charger? Especially for car batteries . . .? For home power plants . . .?
Surely if it was that simple it would have been applied everywhere by now. I’m guessing that that method is not applicable or practical given changes in battery technology over half a century…