I'm really curious about what they've come up with. The only practical way I can think to do this given what we have today is to swap cars.
Elon alluded to it already: http://green.autoblog.com/2013/05/14/tesla-model-s-battery-s...
EDIT: now that I look at the link you added, I stand corrected. From the exploded diagrams, et. al., that I saw it didn't look like it could be swapped out in five minutes. Tesla's designers obviously disagree. :-)
And now that I view the link on a desktop browser, the one who posted it speculates that it's car sharing as well.