Windows 10 typically displays a battery icon in the notification area, also known as the taskbar, when you're using a laptop or tablet. This symbol indicates the current battery percentage. To get it back when it disappears:
The battery icon may still be in the notification area, but it is "hidden." Click the up arrow to the left of the notification icons in the system tray to search for it. [1
If the battery icon does not appear in the Hidden Icons area, right-click on the taskbar and select "Taskbar Settings."
You can also go to Settings> Personalization> Taskbar instead.
In the settings window that appears, scroll down and under "Notification area", click on "Turn system icons on or off".
 Locate the "Power" icon in the list and turn it on by clicking "On". It will reappear in your taskbar.
You can also turn on or turn off other system icons, including time, volume, network, welcome screen, location, action center, touch keyboard, Windows Ink Workspace, and touchpad. 
CONNECTION: Adjust and optimize the Windows taskbar icons  If the Power option is dimmed here Windows 10 believes you are using a desktop PC without a battery. The power icon on the taskbar is not displayed on PCs without a battery.
Even after you restore the battery icon, it has won There is no estimate of remaining battery time displayed when using the mouse drive over it. Microsoft has disabled this feature – probably because it is generally inaccurate. You can still re-enable the battery life estimate with a registration hack.
RELATED: Enable remaining battery life in Windows 10