For what purpose are all those circuit boards
In that bottom card rack next to the APU battery location? Looks like some sort of VME chassis with a shedload of cards...
If Boeing and subs understood the Lithium charging procedure there would be no need for the bigass containment box, just like the little 28VDC backup Lithium pack on the second shelf near the bill of the inspector's hat--iirc that short box has a 7-cell lithium pack with lid openings at all the corners, and it's not going into a vault. Why do you suppose that is the case?
The Aft EE looks like a hail-mary parts bin sale at radio shack--just throw some stuff up on the racks, run some wires and hope it works. Left hand doesn't know what the right hand is doing...Sad