lithium ion batteries have a tendency to overheat when charged continuously because they don't develop memories. Quick fix tell the CPU to stop the charge at 80% and or cool the batteries.
PS: recommend a Halon Fire suppression system for the luggage area on the 787.
Most cargo bays use halon already. It doesn't work on Li batteries. See cut and paste from an article shown below. Maybe something has changed since 2006.
" in the interview with Reuters, Leon said he raised concerns about the safety of the lithium-ion battery that he was using for testing about two weeks before it suddenly exploded in November 2006.
Leon said he tried to put out the fire using halon, a liquefied compressed gas, but parts of the battery kept reigniting."