Cybersecurity threat to aviation: Addison Schonland at AirInsight has been working on a project related to cybersecurity and the threat to aviation. He’s posted this article that raises serious issues.
Lithium-Ion Batteries: On the eve of the NTSB two-day forum on lithium-ion batteries, Reuters has a think-piece about these batteries in general: uses in cars and other products, for example. It’s been a 10-year research project by battery designers. Quite an interesting article.
WA worries about SC: The Seattle Times writes that Washington State officials are worried about the latest expansion by Boeing in South Carolina.
In advance of Porter CSeries order: A lot of Tweeting from an aerospace writer in Canada:
Source says Porter feels city of toronto and Feds willing to revisit tripartite agreement.
Unclear at this point where the Porters CSeries will fly from when its delivered in 2016
Porter Airlines adding Calgary, Vancouver. LA, Miami, and Orlando using CSeries. From where remains the question.
@scottdeveau Porter is seeking a lift on jet aircraft bans at Billy Bishop and aims to add 180 m on either end of the runway for CSeries
Typo or Freudian slip? Brendan Kearney
@NikkiHaley‘s comments on #Boring SC growth plan… (1/?)
@Kearney_Brendan 13m @LeehamNews @nikkihaley ha, typo — and one that I fear making. Usually I catch myself when my thumb strays right on the keyboard.
While the Reuters piece is indeed interesting, I can’t stand it when reporters ignorantly perpetuate myths.
“Meanwhile, Lukso faced the same problem as Boeing – once a fire got started in a big lithium-ion battery, it is tough to put out, since it creates its own oxygen and has its own fuel.”
The electrolyte/anode/cathode decomposition reactions that occur during a Li-ion battery thermal runaway failure do NOT produce oxygen. The reason these reactions are so hard to stop is that they do not depend at all on the presence of oxygen. Since typical fire suppressant systems work by starving a fire of oxygen, they are not effective in stopping the decomposition reaction. The best thing to do is to try and reduce the temperature, which is hard to do with large cells. This is what the first responders did in Boston with marginal success. The reaction essentially ran to completion in several of the 8 cells, although the cooling that was applied probably shut down the reaction in the remaining cells.
I am puzzled by the Seattle worry about Boeing expanding anywhere but there. You have 85,000+ employees in the Seattle area. You have more aerospace projects than you can handle, the cost of Northwest land and labor is sky high (expansion negatives), there are mfg. Space issues and yet you don’t want Boeing to expand anywhere but in Seattle. Is this just part of the entitlement mentality? Maybe it’s the realization that the labor costs in the NW are outweighing the benifits of experience for new projects. Remember that aircraft are built in Atlanta, Fort Worth and St. Louis every day and the workforce in the industry have proven to be very willing to move with the job.
I don’t know if it’s an “entitlement mentality”, people are afraid for their jobs and don’t want to move to the South (who would?). The newspaper has an interest in provoking those worries because it will help them get pageviews, and the Company has an interest in stirring up those worries because it will help them drive a wedge between the union and the employees (probably more effective with the engineers, who like me wonder why we even have a union when our counterparts industry-wide do fine without one) and extort money from the taxpayers. Finally, local and state politicians provoke these fears so that when the aforementioned bad things do not happen, they’re able to take credit. I am looking into the future…I see Jay Inslee making a speech about how he kept the 777X in Everett! I see…state financing! I see…union votes for Jay Inslee!
“Finally, local and state politicians provoke these fears so that when the aforementioned bad things do not happen, they’re able to take credit. I am looking into the future…I see Jay Inslee making a speech about how he kept the 777X in Everett! I see…state financing! I see…union votes for Jay Inslee!”
Such a cynic. 🙂
It is a grammar problem 😉
Mostly about “my” and what relation (relational, posessive, .. ) it actually describes.
( My sister, my house, my wife, my headache, my problem, … See Larry Niven : Draco Tavern : Grammar Lesson 😉
FAL job slots drag a tail of 20 or more jobs in preparatory work behind them.
Even if half of these jobs are abroad that still is quite a bit of a jobmarket cookie.
Attn Mr Bohnet,
“The electrolyte/anode/cathode decomposition reactions that occur during a Li-ion battery thermal runaway failure do NOT produce oxygen”
See http: //spectrum.ieee.org/green-tech/fuel-cells/can-signal-processing-stop-battery-fires
The real issue is nano-FOD introduced in the build process, which deposits on the cathode during charge-discharge cycles enabling the anode-cathode short. Pre-shipping NDI may not detect this FOD, and that may be the demise of this Li ion chemistry.
3 LixCoO2 (Lithium ions intercalcated into Cobalt-diOxyde ) decomposes under Lithium depletion (x } 0) and heat to 1 x Co3O4 and 1 x O2.
Oxygen may exothermically form CO, Co2 with the carbon from the anode.
Uwe, you’re stating the O2 release for a fully delithiated cathode, x=0. This is only the case if the battery is grossly overcharged.
Assuming a full charge voltage of 4.0V, x is more like 0.5. This means that the amount of O2 produced during cathode decomposition will be about half of what you stated, or:
6 Li(0.5)CoO2 = 3 LiCoO2 + Co3O4 + O2
This makes a huge difference in the results of abuse testing. Doh and Veluchamy state that changing x from 0.4 to 0.5 changes the result of spot weld tests from violent gas venting to no gas venting (pg 39, section 3.3). Oxygen is still produced but in much less quantity.
The combustion of this O2 produced via cathode decomposition does not produce a flame. It seems to be more of smoldering type combustion reaction involving a solid oxidizer (cathode particulate Material) and liquid fuel (hydrocarbon electrolyte solvent. This is consistent with measured internal temps (600C) and the fact that Sandia observed no flame during their experiments in Argon.
I expect the postulated “trigger by overcharge” to be true. Even if only for a reduced part of a cell. timing would indicate that imho.
Anyway, whatever oxygen is available will go into partial oxydation of other cell components. View into the deceased batteries shew a foamy coked melange of “stuff”.
Outside you should get traces or more of O2, CO, CO2, F* ( from LiPF6, LiBF4 or LiClO4 salts) and a range of partly decomposed organic carbonates ( flamable electrolyte solvent )
finally: where in the bomb calorimeter any of the available exothermic reactions happen is irrelevant to what happens on the outside of this box. There only the net released energy is of relevance. ( if energy is sufficient to heat the plain battery to 5..600°C the trippled mass should limit that for the complete box to 200..250°C )
What I dislike in the official Boeing information presentation is the reduction to semantics “nonfire” ( but a fire by any other name, limiting the problem by limiting the available vocabulary, a method of bad faith IMHO ) and pushing the most positive outcome to the forefront. This is “marketing ways” and not “engineering ways”.
I agree that a grossly overcharged cell is possible. That is the precise reason why Boeing spent so much time on that very issue. They had to show to the FAA that the chances of overcharge was less than once in 1 billion flight hours. So while it is possible, it was also the failure trigger that got the lions share of the attention.
Again, I want to emphasize that x=0 is only for the case where the battery was grossly overcharged and mistreated by the circuitry. In hindsight, its easy to disagree with their safety design philosophy, but I believe they thought they were handling the worst case through their design of quad redundancy monitoring circuitry.
My point about the O2 is that when it is produced, it is in intimate contact with something. It will not, except perhaps under the worst possible overcharge conditions, produce a flame in the classic sense, imho another reason why Boeing payed close attention to overcharge. This is also, imho, what Boeing was trying to explain when they made the botched statements about how a battery fire is only caused by overcharge. Well, it all depends on what people think a fire really is.
Finally, it is trivial to criticize they way Boeing has handled this with the public. While I do not agree with the way they handled it, I do realize I’m listening to them with the benefit of an extensive technical background. The majority of their audience does not have or has minimal technical background, and to them, fire means flames and something hot enough to at least melt aluminum. It is plain to me that that is not what happened in the JAL battery incident. How do you describe to the public what really happened in a way that is understandable without using inflammatory language (groan) that will get average travelers worried?
Do not make the mistake of thinking, even for a second, that the way Boeing leadership is communicating with the public, represents at all what their engineers and scientists really know about the technical issues.
Hi there again Uwe,
You are right about the relative thermal masses of the battery and the containment box. However, I do think it is important where the heat release occurs within the containment box. For example, if hot reacting material is allowed to contact the seals around the connector feedthroughs, say by splashing or jetting out of the cell case, then the seals could burn through and the gas containment aspect of the box would be compromised. That is why it is a good idea to have the battery case box within the containment box with a moderately sized gap in between.
Mike, you write:
“I agree that a grossly overcharged cell is possible. That is the precise reason why Boeing spent so much time on that very issue. They had to show to the FAA that the chances of overcharge was less than once in 1 billion flight hours. So while it is possible, it was also the failure trigger that got the lions share of the attention.”
The FAA mandated afair in their special condidtions 1/10million hours for a significant battery failure. ( i.e. reduced from “does not happen in the products accumulated lifetime” )
Let me give a dissenting impression then ( which I have been thoroughly flamed for ;-):
The superficially observeable information imho indicates a disinterested procurement decission going by marketing tags “highest energy density”, “highest power density”, “not in Airbus products” that was rubberstamped into compliance with the FAA special conditions.
I would be very surprised if there was spent any significant amount of time on this item before the January grounding. Also for the other electrical problems activity towards solutions seems to have only started in recent time. Most of the design features scream NiCd copy imho. ( also on PPrune someone pointed out strong similarities to the 777 battery connections.)
For a professional entity ( that most everybody wants to asure me Boeing is ) i find this absolutely strange. Like all the 787 problems are just rain squalls that will pass in a short time.
Well, I was wrong about this.
Even though the vent gasses (gasses that escape the battery container) from a Li-ion battery suffering thermal runaway contain no oxygen, as measured by researchers at Sandia, oxygen is indeed produced internal to the battery during the decomposition of the cathode material under high heat conditions, when fully charged or overcharged.
Thank you Ken and Uwe for challenging my erroneous statement. I had the Doh and Veluchamy paper already, but had not read it yet. After chewing through it yesterday, I gained a new appreciation for just how different the wide variety of combustion forms can be.
“.. I gained a new appreciation for just how different the wide variety of combustion forms can be.”
It is a PITA of an ill defined mess. IMHO one would have to design more for worst case than the most benign or the typical situation.
“The Box” appears coarse, unsophisticated but will do its job on the propagation side.
“NTSB Battery Forum” has some interesting reading fodder:
The Processes/QA thing from Saft is noteworthy.
Seems to retrace the MIL / Commercial qualification evolution in semiconductors?
“It is a PITA of an ill defined mess.”
While I’m not a combustion expert by any stretch, I have had to deal with several “issues” on a few systems during my career where I’ve had to sift through the results of complicated unintended and unanticipated chemical reactions. From my experience, given some time these types of things can get properly sorted out and understood. Trying to understand this battery failure for myself is just the first time I’ve had to really think about smoldering types of reactions. The stuff I normally deal with is over in a few milliseconds.
A view from over the fence in programmer land: