A succession of problems has plagued Boeing's 787 Dreamliner, but investigators are now most concerned about incidents involving overheating of lithium-ion batteries.
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.
Auxiliary power batteries onboard a Japan Airlines Dreamliner 787 caught fire at Boston's Logan Airport on January 7. The battery was taken back to the National Transportation Safety Board's Materials Laboratory in Washington for further examination. (Source: NTSB)
Aviation experts said most of the problems are unrelated. "I tend not to believe that there's a single root cause behind all of this," David Freiwald, an assistant professor of aerospace at Embry-Riddle Aeronautical University, told Design News. "Any new system has teething or growing pains. A few issues are to be expected."
The incidents did motivate aviation authorities around the world to order stoppage of Boeing 787 flights, however. The FAA also announced it will work with Boeing engineers to conduct a comprehensive review of the 787's design and manufacture, with an emphasis on the aircraft's electrical power and distribution systems.
On its website, Boeing emphasized the safety of its new aircraft, releasing a statement saying, "The airplane has logged 50,000 hours of flight and there are more than 150 flights occurring daily. Its service is on par with the industry's best-ever introduction into service -- the Boeing 777. Like the 777, at 15 months of service, we are seeing the 787's fleet wide dispatch reliability well above 90 percent."
Most of the concern around the 787 involves the use of lithium-ion batteries. The 787 is the first commercial aircraft to employ them. Its electrical architecture also operates at a higher voltages than predecessors, experts told us. "In terms of the ancillary systems, almost everything on the 787 is electrical," Freiwald said. "Most aircraft systems operate at 115V AC, whereas this is a 230V system. It's a pretty substantial amount of power and current."
Freiwald added that the lithium-ion batteries are used for auxiliary power back-up. In the past, he said, commercial airliners have typically used nickel-cadmium chemistries.
Battery experts told Design News that the choice of a lithium-ion chemistry shouldn't be a problem, but it does call for tighter control. "Lithium-ion is a pretty energetic material," Eric Dietz, a professor of computer and information science at Purdue University, told us. "You've got oxidation and reduction reactions happening in close proximity to one another, so it's important to maintain engineering control around the battery."
At first all the failures may look unrelated due to the fact they all perform different functions on the Airbus.
But before a general comment can be made as in the article, as an engineer, I would investigate the specifications requirements from all these peice parts and check in- fact they have been enviromentaly accepted for high altitude low atmospheric pressure, Vibration of jet engine frequency and air turbulance of sympathetic oscillations, and extreme temperature changes mostly cold temps.
Now if we take all these into effects, I bet we might find a common thread. It cost $$$ for screens like this and BOEING could have cut cost by using "COTS" of the shelf items.
The Lithium batteries were once not allowed on board plane in laptops because of inherient design issues that caused a possible fire. What has changed with Lithium batteries to make them safe???
Someone in BOEING is an Engineer of poor judgement....Not the structure of the aircraft but selected components not purchased properly for the job is whats at fault.
I bought a Cadillac and the dealer gives me a Chevrolet...get my point
I find it ironic that the 787 uses high capacity Lithium Ion batteries for its standby/startup power when such batteries onboard as cargo have had severe restrictions placed upon them in the past. For example UPS considers batteries with a watt/hour capacity greater than 20 but less than 100 to be shippable but only when handled as hazardous material. Anything above 100 Wh is not shippable by air according to UPS. This for a disconnected, not in service battery!
The IATA bans cargo shipments of primary cell Lithium Metal batteries from all passenger planes. Obviously, the button cell in your wristwatch is okay as long as it isn't part of a cargo shipment.
The IATA regulation of 100 Wh or less for secondary Lithium Ion batteries has been the limiting factor for available run time for professional video cameras.
Overcharging is well known to cause overheating. The charging system and overheating protection system need to wwork to prevent this. Apparently this has not been completely effective. I would look carefully at the charging system to see what unusual conditions may exist. Perhaps the intense cold in the exterior environment could trick the charging system into overcharging.
SystemsGuy, my understanding is that this battery came into play only on the ground, i.e. something to do with landing gear controls or something. So high altitude cold air doesn't help that situation much.
In any case, flight controls probably get their biggest workout getting to altitude or landing, all lower altitude issues, and must be designed for the worst case.
Liaison engineers have commented previously that Boeing may have done too much too soon with this aircraft.
We have had lithium systems problems in E scooters where thermal overload shut down the 48V system via the batteries management software. We concluded that heavy current draw during acceleration was causing the problem and tried conditioning that by tweaking the controller
Very good point, davemiga. I've heard -- unofficially -- that it was cobalt, but haven't been able to verify it. And, yes, a cobalt chemistry is slightly more susceptible to overheating, although all lithium-ion chemistries are on the edge (with the possible exception of the so-called "nanophophate" chemistries).
The description of the meltdown seems that they might be using lithium cobalt, not a good design choice if that is the case. Lithium iron phosphate LiFeP04 would be the only safe choice. Anyone know what Boeing used?
Lithium-Ion chemistry is also used in the Chevy Volt, the Fisker and other electric vehicles (but notably not in the Toyota Prius). Li-ion is a very energetic chemistry, which is necessary to pack so much energy in a limited volume. Gasoline is even more efficient, so much so that it can explode in situations where Li-ion batteries would only burn.
By experimenting with the photovoltaic reaction in solar cells, researchers at MIT have made a breakthrough in energy efficiency that significantly pushes the boundaries of current commercial cells on the market.
In a world that's going green, industrial operations have a problem: Their processes involve materials that are potentially toxic, flammable, corrosive, or reactive. If improperly managed, this can precipitate dangerous health and environmental consequences.
With LEDs dropping in price virtually every year, automakers have begun employing them, not only on luxury vehicles, but on entry-level models, as well.
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