The vehicle only has about 5k miles, the battery didn’t fail, it was killed!
The vehicle was towed to the dealer for a stalling/misfire issue. A series of errors in diagnosis eventually led to the dead battery.
In the end the root cause of the original problem was a gas tank full of water. The water didn’t kill the battery, just started the chain of events.
There’s no protections circuits in the modules themselves. The LBC (Lithium-Ion Battery Controller) was removed prior to photos. The LBC monitors pack voltage, current, temperature and the voltage of each cell. Target cell voltage deviation is 200mV.
If I have the time I may open a module, I’ve seen pictures of the cells but haven’t had my hands on one yet. They’re flat cells, similar looking to Li-Poly cells but much larger.
Considering the cost I doubt I’ll have one in my basement any time soon.