Hi,
RetiredF4:
If the "runaway risk" isn´t eliminated...
The idea is based on:
Cell failure MUST not generate battery dangerous heat: Cell separation (physically) could brings this "feature" (Larger case due this) and "Fault tolerance"
Cell failure MUST not degrade abruptly DC battery supply: Two batteries brings "fault tolerance"
Battery management system revision: this could improve cells / battery reliability through derating, better monitoring (per cell temperature, etc.) Statistics vs previous version tend to improve.
Sturdier, vented and AIR CIRCULATION case brings benefits on mitigation and reliability.
then there will be the double amount of non normal events.
Suppose the worst case: Cell´s still fail much more than expected. The likelihood of excessive battery heat leading to thermal runaway is lower than presently. (due better packaging: cell separation, circulating air and venting to outside of a/c.)
Bad for statistics.
Why:
Statistically (at a/c system level) this config. could even improve the a/c. The chance of non availability of battery supply for Bus (MAIN) or APU start will be lower.
The built in benefit is: Certification bureaucracy could led to faster 787 return to commercial operation.
PS
119.4:
Thanks news. Will look for details