Hmm that's a good question. I'm wondering if they have integrated the heatsink part into the conductor strips that connect the cells together. That's what it kind of looks like from the picture. Or maybe they're just tubes between the cells that create a large surface area of metal. The plastic case isn't really an ideal for heat esacpe, but it's probably good enough.
The rest of the 36V Litheon tools are supposed to be due out soon. They've had the drill/hammerdrills and SDS hammer out for a long time, but seem to have been really delaying on the circular and recip saws. The Litheon battery seems to have an actual exposed heatsink with fins on it. I thought too that their charger blows air over those fins too, but could be mistaken on that.
DeWalt's 36V battery is totally sealed and there's no heat conductor or air passage whatsoever. Neither is V28 or V18. Totally sealed batteries.
The 18V 2.4 Amp Hour BLUECORE™ Battery is 2.6lbs. and the 18V 2.4 Amp Hour standard Battery is 2.4lbs.
Each new Bosch BlueCore NiCad battery — 9.6, 12, 14.4, 18 and 24 volt — integrates advanced cooling rods positioned between the pack's individual cells. While other batteries would normally build up hot spots, which speed up chemical breakdown, slow the recharging process and eventually damage individual cells, the BlueCore cooling rods absorb the heat to dissipate it away from the cells. This keeps the battery cool and functioning at optimal levels.