After looking at the picture of the exemplar battery in the NTSB report, one thing puzzles me about the smaller monitoring wires. There appear to be 3 wires that are attached to electrically potential-equivalent points on each inter-cell junction.
One on a cell connector on one side of a battery cell, one on the interconnector that connects to the next cell, and one on the cell connector on the other side of of the interconector. (Hope that is clear)
I cannot believe that these wires are all measuring potential. Some of them are either shunt wires or serving some other function such as temperature monitoring (although how that might happen is not obvious)