First of all, I'm not an electrical engineer and limited in my ability to discuss the advantages/disadvantages of NiCad vs. NiMH vs. lithium batteries. I'll certainly agree that most of the issues with lithium-ion have been in the charging systems and not the battery itself. The problem is when a fault occurs and an overheat or charging malfunction creates a fire, we have one serious problem. In flight, it could easily be a catastrophe.

I think that Boeing engineers were trying to save weight as well as provide batteries with a quicker re-charge time and larger capacity in selecting lithium-ion. After all, this aircraft is not only an "electric aircraft", it takes that concept to a new level. Any engineers on the forum please correct me if I'm wrong. The bottom line is that the containment box, no mater how well designed probably will not completely contain a lithium fire and therefore an extinguishing agent must be developed that will actually extinguish a lithium fire in-flight. Until that can be demonstrated, there is a risk in operating the 787. Obviously the FAA felt the same way.

I fly RC aircraft and the lithium-polymer batteries are commonly used. I have seen a li-po battery fire and it's not a pretty sight. Keep in mind, this was in an RC aircraft.

Y'all be careful out there !