Idea of Low Battery Icon
This shape is basically a rectangle with rounded edges. On the right center of the shape, is what looks like the right side of a regular rectangle protruding outwards. On the inside are two vertical lines on the left.
This page contains the Low Battery vector icon, as well as variations of this icon in different visual styles, and related icons. All icons are in the flat vector style, however, differ by the line thickness, fill, and corner radius.