Idea of Battery Level Icon
The logo for a "half-charged battery" is a battery on its side. When the battery is full it will have a number of vertical lines to fill up the space inside the battery. As the battery life drains, the lines representing the percentage of battery life are left. When the battery is half-charged, only half of the battery has these vertical lines.
This is the Battery Level icon for Windows 10
. Here we go. Optimized for 32x32 px, these are the simplest icons in the line style. Downloadable formats are PNG and SVG, among others. Icons8 icon pack is unique in providing a huge number of icons designed by the same team of four designers who create the new icons every working day in the same style and with the same quality. Same cool as the Bat Face, huh.