I looked at the next video in the series and he took the innards out and it wasnt a pouch at all. It was two REALLY long flattened jellyrolls with aluminum and copper tabs spaced along it that were gathered up to make the tabs. The edges weren't sealed just open to the case so what he poured out was the actual operating electrolyte. He found on one of the jellyrolls that the copper anode (cathode?) wasnt covered in the LFP material and evidently shorted to something.If it was electrolyte he poured out of the case in the video, then one or more of the pouches leaked.