The new one on the right looks to be a simple open box (no top cover) - gotta wonder why it isn't in a flame-proof steel box that would help prevent fire. Perhaps better that than an explosion.
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 battery’s burned insides indicate it operated at a voltage above its design limit, a Japanese investigator said Friday. That’s 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 ...
If Boeing were forced to replace the batteries in the Dreamliner, that rigorous testing would be a fresh problem.
“The redesign is much smaller than the extensive testing that would go on, that would be time consuming. We’d be talking about months. Many months.”
The new one on the right looks to be a simple open box (no top cover) - gotta wonder why it isn't in a flame-proof steel box that would help prevent fire. Perhaps better that than an explosion.
Exa Rong Rife
Interesting. I wonder if aircraft testing included a scenario that simulated a ‘fully-loaded’ stress test over a long period of time..in other words, having every appliance turned on in the kitchens, cockpit, not to mention all the music ports, movies and computer users, etc.
I’ve seen larger metal cased battery packs oilcan before...and split metal, even along welds.
A power source, like a battery (meaning multiple cells), without the means to shut down the individual cells via a fuse or switch is simply asking for trouble.
Some batteries are safer than others like the good old, heavy, lead acid batteries in our cars but these newer batteries are KNOWN to overheat and to build a battery in a mission critical application like an aircraft is beyond stupid. From laptops to electric cars and now airplanes it should be obvious to anyone who knows which direction electrons actually flow, you need protective devices at the cell level.
Wrong. These are Japanese made batteries.
Sad to say!
Most people don’t understand this mess. Anything — ANYTHING — that is installed in an aircraft as equipment, has to be tested and paper-worked to death. It’s weight and effect on the CG envelope has to be discovered and then allowed per FAA regs. All — ALL — ops and maintenance manuals must be approved by the FAA and then supplied to all users. The supplier has to be officially blessed by the FAA and no — NO — non-approved device or part can be used or even mentioned. The part supplier has to undergo the equivalent of a military TS background check. The legal liability assumed by a supplier and builder is open-ended. You cannot add a four-pound GPS to your Cessna’s panel without a complete rework of the airplane’s paperwork. Then, after all that, there is public perception. Boeing is in deep trouble. So is the current battery supplier. Law suits will be ongoing for the next 15 years. The Lockheed L-188 Electra suffered four crashes before it was discovered that engine mounts were failing. It never recovered, although the Navy bought it as the P-3 with wing re-working.
Exa Wong Wife
Wurlitzer has one possible and obvious answer - "...the means to shut down the individual cells via a fuse or switch is simply asking for trouble."
Too, why not a built-in over-heating alarm.
A whole bunch of people haven't done due diligence here.
loads you mention are not suported by the batteries,wouldnt make a dif.
This was/is a design flaw and IMOP related to improper charge and discharge resulting in thermal runaway resulting in the battery case being consumed by intense heat
While I certainly cannot, nor should not, dispute a single thing you posted, it is amazing after all that GOVERNMENT paperwork, they would allow a battery design, with cells known to overheat in many other applications, on an aircraft.
The only semi-safe design for these batteries are to have every cell contain a thermal trip device such that on cell cannot generate enough heat to cascade other cells into a ignition source with NO internal off switch. Once they start to overheat they take on a life of their own.
These are balancing chargers -- at the cell level and 4X redundant. Still, even with the redundancy I think this was more likely a runaway charging problem, although the lithium cobalt oxide chemistry is more sensitive than lithium iron phosphate would be and only slightly higher in energy density.
True, the cobalts start to generate their own oxygen in a big way.
We got new sonobouys aboard the P-3 for a time that had lithium batteries. They were so dangerous that the Navy instituted special, new procedures for jettisoning the things if they caught fire.
Interesting comment! One has to wonder how these planes were certified by the FAA. Perhaps they were partially built in Japan, escaping some of the FAA regs?
Computer design is a tool. It is no replacement for human experience. The 787 relies on too much on technology, and not enough on basic aircraft design. Trying to squeeze every ounce of weight and inch of space has come back to haunt them.
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