In FO3 and NV (and before if you get down to it), all energy weapon cells are pretty much treated like individual bullets, instead of containers of electricity or electricity-producing materials
I'm kinda hoping that they implement a system where a cell is stated to have X charge points in it, Y maximum charge points it can hold, any given E-weap uses Z charge points per shot, and the cells are rechargeable. It would give energy weapons a different paradigm to keeping them properly fed compared to Guns.