there is the standard which i3 is using http://en.wikipedia.org/wiki/SAE_J1772 that in itself has (incompatible?) AC (2 levels) and DC (3 levels) variants
then there is this with a completely different plug http://en.wikipedia.org/wiki/CHAdeMO
and another standard http://en.wikipedia.org/wiki/VDE-AR-E_2623-2-2#VDE-AR-E_2623...
China will use yet another one http://www.longtailpipe.com/2014/02/chinas-electric-car-fast...
Oh and then there's Tesla's supercharger network