Sankar has been saying very confidently that their batteries are better than Tesla/Panasonic's. It might be because he's had that "confirmation" from another entity that used both for a while.
That "tip of the iceberg" talk and some other quotes such as "small deal" and saying that they only gave the batteries and modules to select customers for testing has me thinking that there is most likely one especially huge deal in the works.
If Daimler is it, I wouldn't be surprised.
Also, as far as I remember from what I read, Daimler said they were going with LG for the 2016 generation of the Smart EV. That was quite specific. They didn't say they were going with them for all their battery needs until further notice...