hi,
http://www.oplaadpalen.nl
This map shows charging points for BE and NL.
Notice that there are many owners (eigenaars) and payment methods (betaalmethode).
For many payment methods you will need a card (or even a yearly subscription) but some charging points are free (gratis), however none in belgium it seems (nothing free in BE, but we do have the highest taxes for EU...).
You can select your vehicle type (mijn voertuig) in the pop-up list on the right also.
In many cases you can also see if the charging point is occupied ot not (realtime).
I'm not a i3 owner yet and don't have any experience with these charging points myself. But maybe a warning, belgian charging infrastructure is lagging far behind compared to the Netherlands.
I would expect that you can find those charging points on your i3 navi also.
Good luck and have a nice trip !
PS: stay out of Brugge, you might get arrested !