Surprisingly, I have to say that the battery releases the energy stored when needed and as electronic devices such as the Samsung Galaxy S4 drives. The Oberhammer is that when the power source is used, it can be recharged. Over and over again. Simply brilliant.
One could call this energy source (ie that housing) also use as a doorstop or paperweight. Would not as effective but nevertheless conceivable. There are certainly other ways so creative since.