PPRuNe Forums - View Single Post - 787 Batteries and Chargers - Part 1
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Old 18th Feb 2013, 05:43
  #713 (permalink)  
Join Date: Aug 2011
Location: Grassy Valley
Posts: 2,123
From the first photo of the series connection of the eight single batteries, why speculate there was individual monitoring? What could be done? Only one thing, switch out the entire battery group, at least to prevent any aggravation from continued discharge/charge?

All the talk about sensing temperatures at each battery, and even separate locations within each battery's cells, is a red herring. There is no way to "shut down" any one of the eight batteries connected in series.
It appears attempts to insulate each individual from another were made. Even if one could be switched out, that leaves the remaining number to be vulnerable to abnormal current and voltages? I think this system works as a unit, or it shuts down. NTSB states that JAL started with a single cell failure; designed containment failed. ANA the same?

An argument could be made that containment did function satisfactorily. That is a judgment FAA makes. But then it remains to also argue there was no "thermal runaway", only something 'less'. That might be a tough sell.

Trying to improve 'containment only' does not meet the regs. That implies a thermal runaway is tolerable. If it was, it won't be now....

NTSB would have to clear the current manufacture as something it has shown itself not to be, 'resistant to flame/fire'.
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