The basic building block of a battery.
1Now both of them knew that, once the source of power was used up, that was the end of that energy cell.
2We had to replace the energy cells, but it still functions".
3She waited, as the energy cells of her memory began to charge like complex batteries.
4Husband and wife checked each other out: oxygen, tools, lights, energy cells all in place.
5The main energy cells are dead.'
6The battle escalated into a full conflict, and soon, both sides no longer had any power left in their energy cells.