@Lyman
I apologize for explaining things poorly. You help me to manage my posts better. Thank you.
By "Management" I refer to action it takes, to meet the objective of reliable and safe operation, irrespective on what takes the action.
Rather, by what we see, all boils down to inadequate management, on all levels.
- Primarily, of the cells, so they short. BMS fault
- Management of cells includes control, monitoring and balancing to assure reliable and safe operation.
- Control of battery charging
- Monitoring of cell voltages and battery current and temperature
- Real time determination of battery status and cell condition
- Battery voltage
- Battery current
- Battery temperature
- Cell voltage
- Cell voltage transients at individual cells. This is needed for cell short detection.
- As discussed earlier, cell pressure would be an interesting alternate way to detect cell shorts. This is optional.
- Balancing of cells by discharging cells at or above 4.025V
- Secondarily, of the cell short, leading to the conflagration BMS fault
- To prevent cascading failure after a cell short
- Disconnect battery
- Prevent charging .
- Prevent current flow into cells
- Apparently, at TAK, connections were found between APU and Main batteries (via Nav lights), which were not part of the design. Production QC fault?
- That 100+ batteries got line replaced Inaction?
- Problem persisted after a year in service until the grounding
A Nail is better than....What?
- A short by a nail is a bad test
- It is not realistic
- The short circuit resistance will be lower than a genuine cell short
- A good test would be representative of the smallest internal short, which could lead to damage to cell.