RR NDB writes:
My comment is because considering certainly there is no discharge control (perhaps will be required for Li Ion in aviation) the analysis is concentrating in:
I'm pretty sure there is, it would be inconceivable to connect an uncontrolled load (ie DC starter motor, etc) directly to any Li battery. All of the "big" loads on the 787 are AC or driven from the +/- 270V DC bus and have no direct connection to the battery buses. The APU starter is a starter/generator which has its own (load-limiting) controller when using the APU battery for start power.
The simplified graphic in this post shows high-power distribution.
We're getting closer to the reason for at least one of the failures. Flightglobal writes that a short was found in cell # 5 of the JAL battery.
Story with pix here.