Hello i think i found the link between what he said and reality...

When an electric charge is in motion it is called current, which is measured in amperes (A). One ampere is equal to one coulomb of e lectric charge per second past a defined reference point. The electric potential between two points, defined as voltage (V), is the work measured in joules per coulomb (or voltage) necessary to move a unit electric charge between the two points.

Voltage is the work measured in joules per coulomb necessary to move one coulomb between two points in a circuit.

So this mean that for every electron you need a bare copper ion for the current to flow...

http://www.vitatech.net/emf_fundamentals.php4