Posted on 01/18/2013 12:56:33 PM PST by Ron C.
A charred lithium ion battery at the center of the worldwide grounding of the Boeing 787 Dreamliner showed evidence of thermal runaway -- which is indicative of a design problem, experts tell FoxNews.com.
The All Nippon Airways plane made an emergency landing Wednesday morning in western Japan after its pilots smelled something burning and received a cockpit warning of battery problems. Nearly all 50 of the 787s in use around the world have since been grounded.
The batterys burned insides indicate it operated at a voltage above its design limit, a Japanese investigator said Friday. Thats a clear sign of an out-of-control chemical reaction, explained Reginald Tomkins, a professor of chemical engineering at New Jersey Institute of Technology.
(Excerpt) Read more at foxnews.com ...
“....which is indicative of a design problem”
They were designed to last for the life of the aircraft, so technically, there is no design problem.
Yuasa. Well known in powersports applications and one of the most respected. Have to remember, they “built to specification”. These young engineers at Boeing now are far too biased toward the bleeding edge and now some of them won’t fly in their own airplanes.
Appreciate your response and the clarification. THose cables in that picture along with every other component are fried. There’s a lot of people in trouble right now..I wouldn’t want to be in their shoes. But I’m even more thankful that no one was hurt.
It will be interesting to see the failure analysis.
They were designed to last for the life of the aircraft, so technically, there is no design problem.
Much like the lifetime guarantee on pacemakers.
It’s my understanding that although the manufacturer certifies the aircraft safe, the individual nations operating it certify it separately for use in that country’s airspace. Such a system has been used to keep a competing country’s product out.
I am curious is this the Lithium-Ion Phosphate which are more geared towards aviation use (just got on my radar screen recently).
The L-188 Electra never recovered because the jet age had started. Many pilots say the Electra was the best plane that they had ever flown in their careers. The tv show Ice Pilots features them still flying for Buffalo Airways in Yellowknife, Canada.
Hmmm...
It sounds like Boeing is covering their butts.
I've been using these batteries for almost 10 years and when the batteries are manufactured, the nominal voltage is 3.7 volts per cell. The maximum per cell voltage in a fully charged state for a properly charged battery is 4.2 volts.
The only time they go into a thermal runaway state is when they are charged to a state above 4.2V per cell or if they are discharged at a rate higher than their designed to deliver.
In both cases (over-charge and over-discharge) they will develop internal shorts which trigger the thermal runaway.
I've never heard of a Li-Ion battery going into a thermal runaway all by itself.
One of the unique features of Li-Ion batteries is the ability to wire them in series and parallel at the same time. This allows the batteries to be formed into packs that deliver a higher voltage and capacity. When wired in parallel, each cell must be balanced before or during the charging process to ensure that each cell's voltage never rises above 4.2 volts.
If one cell resting voltage is higher than those of the rest of the pack, and each cell's voltage is not monitored during charge or if all the cells in a pack are not balanced with each other before charging, then it's possible to over-charge a single cell above it's maximum rated voltage, which will trigger a thermal runaway.
Once a cell goes into thermal runaway it can trigger other cells.
If you're talking about Lithium batteries, they have a maximum life of about 2-4 years, whether they're used or not. Depending on how they're used, this could be shorter.
They definitely won't last the life of the airplane, which is 20-30 years.
Why not just get a windmill from a wind farm bolted to the undercarriage. Voila! No toxic lithium and no overheating battery.
The batteries really don’t power anything unless ground power or on board generator power is not available. They are back-up/auxiliary power only.
“In the case of the 787, two 32-volt lithium-ion primary batteries provide power as key elements of the aircraft’s more-electric architecture. The main battery, located forward in the electric/electronic (E/E) equipment bay below the cabin floor by the front passenger doors, provides power for aircraft start-up, ground operations such as refueling and towing, and acts as backup power for the electrically actuated brake system. It can also assist the second battery, located in the aft E/E bay, in starting up the auxiliary power unit (APU) and, in the event of a power failure, energizes essential flight instruments in the flight deck until the drop-down ram air turbine spools up.
The battery that caught fire on the Japan Airlines 787 in Boston was the second main battery. This unit’s primary purpose is to electrically start the APU when neither of the engines is running and the aircraft is not connected to external ground power. In this case, the battery energizes the righthand of the two starter/generators connected to the APU. The aft battery also provides another minor role, namely to power navigation lights during battery-only towing operations.”
http://www.aviationweek.com/Article.aspx?id=/article-xml/AW_01_21_2013_p22-537845.xml
I should clarify that I was talking about Lithium Ion cells which are rechargeable and not Lithium cells which are not.
Lithium cells, such as watch batteries have a very long shelf life, whereas Lithium Ion cells have a limited life span, depending on their operating environment.
Now all they have to do is figure out why the windshield cracked ad the fuel leaked.
Airliners have electrically heated windshields. It’s not unusual for the outer pane to crack from the heating and cooling of the panel. Only the outer pane cracks. It’s alarming, but not too serious. The integrity of the windshield is not compromised when this happens.
Airliner windshield panes crack fairly regularly.
didn’t they learn from klinton and flight 800?
Were offending batteries made on the same day. Reminds me of Detroit production line scenerio...What was the BAD day? Hummm
Thanks for correcting my spelling.
No doubt the battery company followed Boeing’s specs...
Many of the problems with this airplane can be traced to so many outside suppliers in various countries.
I heard the other day that lithium batteries are not allowed as cargo on aircraft after a crash that was thought to have been caused by a number of such batteries having caught fire.
If they didn't, it would be almost criminal. I can't imagine why these flaws are just coming to light after the years and years this plane has been in development. It sure puts Boeing in a bad light.
Several years ago, there was a great deal of discussion on FR about the 787 vs. the hated A-380. Well, the latter did have some problems at start-up, but has become a noncontroversial part of the fleet. This business with the 787 is disheartening.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.