Boosted Board V2 Battery Type?

[s28400]

So I'm trying to figure out what types of cells the new boosted board uses. The first one uses a123's 26650 cells which are 2.4Ah and LiFePO4. They have somehow managed to double the capacity (199Wh vs 99Wh) while only adding on 340g and a few mm of height. I really want to know what cells they used.
Here is what I know:
Pack is 12s
Cells are about 28 grams each
Cells are about 2.4Ah each
Probably Isn't lipo as they are too dangerous
Full pack has to provide at least 60A continuously
The only cells I know that are close are the 26650's and lipos, but the 26650's are too big and the lipos don't meet safety standards. So what are they using?

 

[Ohbse]

It's definitely lipo. Nothing else approaches the power and energy density. Lipo isn't dangerous if you're using high quality cells, adequately protected from physical harm as well as stringent controls around voltage. It gets a bad rep from shitty products.