So i was watching a teardown of a charge 5 and saw that there are screws that need to be unscrewed in order for the ,,skin'' of the speaker to come off,
JBL Xtreme 3 Review - RTINGS.com
For JBL Charge 3 Battery 3.7V 6000mAh JBL Xtreme Battery GSP1029102A for JBL Speaker Bluetooth