You mean the status bar battery icon? There is none. The only thing you can do is hiding the percentage number from inside the battery icon but you can't change the shape or size of the battery icon.
Yeah I wish they had an option to change the battery icon to circle or an option to remove the icon altogether and just keep the percentage (like 90% without the battery icon). I do not like the new battery icon at all. It's way too big for no apparent reason.
