peter we:
I don't believe this. Every LI battery has protection against such possibilities because of the well known danger. A $16k battery in a critical safety situation with a revolutionary over/under charging system failed in its most basic task?
Comments have been made about this, and the only information I have seen is that there is undervoltage protection in the BMU at the cell level which will disconnect the battery and/or notify the BCU which will disconnect the battery.
But once that has been done, the battery is locked into this state and must be returned to Yuasa.
Based on more information since then, I suspect that part of the problem may be that the protective contactor inside the box is Normally Closed, so disconnecting the battery at that point requires constant power consumption which might take the battery from there down to the irreversible level for the cell or cells involved. Or at least requires Yuasa to evaluate its condition.
In the event of overcharge, using an NC protective contactor would be just fine.
Unless, of course, a failure inside the battery of one or more cells dropped the voltage below the operating point of the contactor.