@OpenCirrus619: do not underestimate Boeing
Don't be so sure Boeing has not identified the cause, or at least some likely cause(s).
I think they have clues, but prefer not to tell, partly because they are not quite sure it is cell damage by deep discharge, water condensation leading to damage by electrolysis, internal cell short by some foreign material, or something else; partly because that would make more painfully apparent that the reasoning in the original certification was bogus, and passengers at (some, likely moderate) risk in previous flights.
So they take steps to mitigate the consequences of a thermal-runaway(-at-the-cell-or-battery-level as they call it), with this (not-a-)fire box, and frankly I think it is a sound safety measure given that they keep the same chemistry (perhaps, because of the peak power and relatively high voltage needed). And they take measures to operate the cells in a reduced voltage range, to less stress them. And they implement some (untold) improvement in the cell construction or/and screening. And use better fasteners, just in case. I only wish we had more details on the identified possible root cause(s) and how the measures resolve them. I do not despair that it will come.
Last edited by fgrieu; 20th Mar 2013 at 19:47.
Reason: Change the possible reason for not using Ni-Cad