Lithium-Ion Batteries Possible Culprit in Dreamliner
Lithium-Ion Batteries Emerge as Possible Culprit in Dreamliner Incidents
Federal Aviation Administration (FAA) officials grounded Boeing's high-tech Dreamliner after battery electrolytes reportedly leaked from a lithium-ion battery onboard an All Nippon Airways flight on Wednesday. The liquid reportedly traveled through an electrical room floor to the outside of the aircraft, leaving burn marks around damaged areas.
The latest incident followed on the heels of two battery-related problems encountered on Japan Airlines flights and another on a United flight earlier this month. Those incidents happened in parallel with multiple other episodes, including two fuel leaks. Since July, the 787 has also encountered a damaged cockpit window, an oil leak, and two cracked engines, according to multiple news reports.
What happens is that metallic lithium deposits on one of the electrodes during over-charge and then explodes when liquid electrolyte becomes too warm due to hot environment and/or over-discharge.
I recall this happened with a Chevy Volt battery which caught fire days after it was overcharged ... during safety testing. LiFeSO4 and even Li-polymer batteries are safer for vehicles.
P.S. A typical airplane will have hundreds of lithium-ion batteries on-board inside phones, laptops, cameras etc. But of course they are small and usually incorporate smart charging ICs.
P.S. A typical airplane will have hundreds of lithium-ion batteries on-board inside phones, laptops, cameras etc. But of course they are small and usually incorporate smart charging ICs.
I think the majority of Li-ion mishaps happen during either heavy charging or overcharging, or during heavy discharging. Anything checked in is probably not charging, and I assume that most devices are either turned off, hibernating, or at least in sleep mode, so barring some other failure causing a short, possibly even internal to the battery, heavy discharging is highly unlikely.
Personally, I think major Li-ion batteries should be put in a stainless steel enclosure -- should they leak or catch fire, the enclosure would at least localize and contain the mishap.
I do not think passengers are allowed to check anything with a Li-Ion battery just in case it starts on fire.
Not true, I check stuff with Li-Ion batteries all the time. While you cannot check loose batteries, batteries that are installed in devices are fine and loose batteries may be carried on. »safetravel.dot.gov/whats ··· ies.html
Yep.. all shipments of Lithium-Ion has to be ground service only..
Also not true. Small quantities of small batteries (<20Wh/cell and <100Wh/pack, and total weight of all batteries in the shipment <2.5Kg) are fine. Bigger or a larger quantity is ok with proper labeling and a Dangerous Goods contract. »www.ups.com/media/news/e ··· ries.pdf
Trial by fire: Boeing should have chosen a safer type of lithium-ion battery chemistry for its 787
quote:Boeing did not choose the safest battery type. The 787’s batteries use a material known as lithium cobalt oxide (LCO), which imparts excellent energy density. However, there are known LCO safety concerns, most notably that the material does not resist overheating well. Once started, Li-ion fires typically generate oxygen and are very difficult to extinguish: The first 787 battery blaze took 40 minutes to snuff out, injured one firefighter, and damaged the airplane’s equipment bay.Boeing should switch to a safer cathode material. In choosing LCO, Boeing eschewed safer alternatives such as lithium iron phosphate (LFP). Even when overcharged, LFP changes only slightly in structure, preventing oxygen release and resisting thermal runaway.
I have several friends who works at Boeing, so I guess I have to hit them up on this.
I don't know a whole lot about Li-ion either, but according this battery university page, Boeing definitely went with the highest capacity variant. And that's probably not the smartest idea in an application where safety is paramount. Wonder if going with LCO was primarily an engineer, project manager, joint, or 'forced' joint decision.
I've played around with a couple of Li-Poly and they are great but they scare me. These are small so any fire is containable
Unfortunately even the smallest li-poly or li-ion battery could create a really intense molten blob of lithium which can start a fire on some other stuff.
»www.luxresearchinc.com/n ··· 148.html - Boeing did not choose the safest battery type - Boeing should switch to a safer cathode material - Regulatory changes should be expected
P.S. My cousin, who ran a small solar/LED business back home, recently died when his laptop started a fire to his bedding/clothing etc. Mom says he was depressed (wife left him with son, lost day job, etc) so it is possible that he was suicidal but most probably he just fell asleep. Photo of his laptop here: »ns.bdnews24.com/details. ··· 59&cid=2
"It's a no-brainer," Elton Cairns, a professor of chemical engineering at the University of California and a nationally known battery expert, told us. "If they used a cobalt oxide chemistry, then the battery should use a cooling system."
The answer seems clear from observations in the 2nd page of this excellent article: Chevy Volt, for example, employs liquid coolant that circulates through 1-mm thick channels machined into 144 metal plates ... Prius PHV plug-in hybrid uses specialized fans, intake ducts, and 42 temperature sensors to actively monitor and cool its lithium-ion battery.
Lithium will react violently with any moisture/water content in a liquid coolant and the system will have more weight. So I think the Prius solution is better for airplanes since they can also make use of cold outside air.
So I think the Prius solution is better for airplanes since they can also make use of cold outside air.
Well, unless the plane is on a runway in 110F weather...
That is actually no different than a Prius owner enjoying air conditioning and sound system while idling on black asphalt in Death valley.
Getting serious about design possibilities, perhaps add thermo-electric cooling when ambient is above 40C and dissipate to lightweight heatsinks around the pack which are fan cooled to stay below 70C.
An inspection report says: "Airline safety inspectors have found no faults with the battery used on Boeing's 787 Dreamliner, Japan's transport ministry has said." »www.bbc.co.uk/news/busin ··· 21230940
One of the reasons I retired was that I got tired of arguing with my boss who loved numbers and everything was approached that way. I would go more on instinct.
I only mentioned this because it seems that things were done here that should not have been done (IMHO) regardless of the numbers.
My uninformed guess is that batteries are probably not the only cause of the 787 electrical problems but nevertheless battery fires are not something to treat lightly on an aircraft. One would like to see intrinsically safe systems not prone to thermal runaway.
Nikkei economic daily said they were looking into a company based in Fujisawa, southwest of Tokyo, which manufactures devices that monitor voltage and temperature in the batteries. That company my end up being the scapegoat for something GS Yuasa should have checked/fixed before supplying the "battery system" to Boeing.
»www.ainonline.com/aviati ··· atteries Jan 21 article says Since October last year there have been 132 incidents involving battery overheats or fires aboard aircraft, according to the FAA.
It look like it was due to battery cell failure not something external. Contrary to what I've seen in some of the MSM the NTSB is still investigating root cause.
I'm not sure what's exactly in those battery packs (aside from the obvious!), but I think the following will be mandated, unless the cells are inherently safe of thermal runaway: a) all individual cells should contain at least one embedded temperature sensor b) cells must have sufficient spacing and/or thermal insulation between them, so one faulty cell cannot overheat the neighboring cells even in case of a catastrophic failure
After looking at the internal photos of the good battery, I agree with you completely and I will add that they should also use insulated wiring harnesses from cells to the BMS PCB.
I think the damaged electrode (slide 11) shows some metallic lithium build-up discussed earlier.
quote:Airbus has started informing airlines that have ordered the new A350 that the new plane will have Nickel-Cadmium batteries, rather than lithium-ion batteries, the European plane maker told CNBC Thursday.
Airbus said the move is based entirely on reducing uncertainty in the program schedule -- not due to any safety concerns.
Airbus will continue working on eventually using lithium-ion batteries in A350 models, but until questions about the reliability of those batteries are resolved, the European plane maker will use nickel-cadmium batteries.
As an aside, why didn't they use at least NiMH? I think it's at least twice the capacity of NiCd.
)
they are buying Yuasa or as we used to call them Youasshole 
·
·