Energy cells (also called Energy Projectors) could be equipped to certain melee weapons, allowing the weapon to inflict energy based damage in addition to slashing damage.
This made the weapon more powerful and more versatile. The best energy cells (Mark III & IV) could provide extremely high energy damage that rivaled the amount dealt by a a lightsaber, in addition to the slashing damage, making a vibro weapon with an energy cell incredibly deadly. This energy could take up a number of forms, the Mark IV Energy Cell produced a sheath of lightning on the blade, which could be turned on and off at will.
- Star Wars: Knights of the Old Republic (First appearance)
- Star Wars: Knights of the Old Republic II: The Sith Lords