I understand that, but did the cell fail from being overheated, or did it become hot because it had failed? The folks at Tesla and others have said that this type of pack requires active cooling. If that's true will an overheated cell fail by shorting, or was the cell poorly constructed, shorted and then caused the thermal runaway?
the cell presented is not the one from 787 but the technology should be similar.
The 787 battery pack has 8 cells serial hard connected. The cells can not be individual switched off in case of failure. The damaged cell still getting power from the good cells and aggravate the issue.
The classic question. Was it a manufacturing problem in the battery pack that caused the cell to short or did the pack overheat and then a cell failed, as so many people looking from the outside have suggested?