O Greenify one of the best and best known apps for controlling battery usage by apps. It does this by hibernating background applications. With the last update, this made it even easier to do this, even on non-rooted devices.

Application hibernation. / Greenify
Since last week Greenify has been able to automatically hibernate applications even on non-rooted devices, ie it is no longer necessary to manually hibernate. To do this, you only need to enable the function in "Experimental Functions …"; however, this does not work if Screen Lock is enabled. In this case, you can create a "Hibernate and Lock Screen" shortcut, which hibernates the selected apps and turns off the display. This function is available in the free version of the app..