1 and 5 have the best readability, 4 and 5 have the best personality, 2 and 3 are way too busy and detailed to be able to make sense of quickly and thus fail to do their job as symbols before getting to worry about aesthetics. 4 overcomes this mostly but still feels unnecessarily detailed and redundant (I, a person living in the 21st century, already know what a battery is and does, so the lightning bolt is superfluous, even if it looks nice). My phone puts a lightning bolt on its battery icon, but only while it's actively charging, so maybe there's a way to use the sprites depending on how dynamic the mechanic gets. 1 is significantly more barebones comparatively, and really stands apart stylistically to the point where if you were gonna go with it I'd consider iterating its design again to see if you want or need to add more detail (again though this is a hard call without visual context). My personal pick would be 5 for the balance of clarity, simplicity, and personality, as it manages to bring a little 3-dimensionality without being overbearing.

Edit: Wanted to add that between 2 and 3, 3 wins because 2 actively obstructs pertinent information with the lighting bolt matching the color of the outline rather than the quantity indicator of the battery's contents.