The Tesla energy cell was one of the discoveries made by Doctors Von Essen and Fassenbiender when they were working for the German government during the Great War. Using the research (and named after) Nikola Tesla, the Tesla energy cell generates and stores vast amounts of electrical power. The Tesla energy cell, however, is extremely volatile. It was never deployed by the German military during the war because a single stray round would cause the cell to suffer a catastrophic exothermic breakdown.