B787 battery
Cell failure - multi current paths involving metal cased cells & metal battery case all resulting in further cell failures currents via earth straps bonding, heat etc. If need to stay with the same cells. Answer redesign battery case for temps above 800 degs C without metal. Material- basalt internal with kevlar external safety outer. Basalt & kevlar dividers between cells. Good for over 1600 degs C. No shorts, no ground loops, light weight.
Most batteries changed because they had been discharged too far. (ground handling?) It is most likely to be found the underlying reason for the two major failures. State of charge indications as a percentage comes to mind. If it at the present displayed as a percentage, then the low end should be recalabrated. If it is voltage it is just wrong. ( don't have how it is displayed & could not find ref in the thread.) The voltage indication of Li-Ion batteries between good & bad are too close for voltage readings anyhow. (coulomb counting for short term indicating)
Regards
Last edited by bill good; 11th Feb 2013 at 09:30.
Reason: ps