Who's bright idea was it to use Lithium-anything as a main battery on-board an aircraft, given all the problems of just transporting the things as cargo?
TNT have this to say:
TNT Express - Lithium Cells and Batteries
I guess the 787 is a flying dangerous goods?
Following several serious (fire) incidents during transport, the regulations for this product type were adjusted and the more stringent regulatory requirements were introduced in 2009.
...and in the 787 they are not only transporting them, but are connected to chargers and are in constant use!