The cars aren't dipped in paint at the factory. They are dipped in baths for cleaning and rust proofing but not final painting. Final painting is done by robots with built in "spray guns". But you are right about the electron charge. Factory paint has a chemical and electron property that allows it to adhere and dry quickly.
The process of spraying the paint in the factory is also very precise in terms of how well the paint is mixed and atomized before it hits the surface. Let face it, a guy waving a spray gun, even a very expensive spray gun in the hands of a pro, is never going to be as good or achieve the same result as a million dollar robot wielding a million dollar specialty nozzle that mixes, atomizes and electrolyzes the paint finer than the human eye can see.
Here is a little factoid I found....
OEM Auto Paint Finishes