Help-me
 

How does the process of recharging of the batteries? and why the submarine it is on surface during charging?

Batteries are recharged by electric generators powered by one of the diesel engines, so the sub must be on the surface, or using a snorkel, to supply the air needed to run the diesel engine.

But when the submarine is submerged, and not the electric motor that works?

The batteries are used to power the electric generators to provide propulsion and power the submarine.

Yes I understand, but what I didn't understand and that when they are using the Snorckel the submarine is submerged and as it is loading the batteries if the diesel engine is stopped

When the snorkel is used they are running the Diesel engines drawing in air through the snorkel.