Apparently the 9v battery runs enough current through the metallic case of the battery to melt and release the adhesive so you can pull the old battery out. See

Apparently the 9v battery runs enough current through the metallic case of the battery to melt and release the adhesive so you can pull the old battery out. Seems like a pretty clever solution, if not a bit over-engineered: https://www.macrumors.com/2024/06/28/new-battery-replacement-method-with-iphone-16/ https://www.macrumors.com/2024/06/28/new-battery-replacement...