I think "vettore elettrico" is likely to be the same as "vettore energetico". The Italian Wikipedia article for this term links to the English "energy carrier".

"An energy carrier is a substance (energy form) or sometimes a phenomenon (energy system) that contains energy that can be later converted to other forms such as mechanical work or heat or to operate chemical or physical processes. Such carriers include springs, electrical batteries, capacitors, pressurized air, dammed water, hydrogen, petroleum, coal, wood, and natural gas."

I'm guessing that in this context, the carriers/storage devices are batteries.