21700-cell batteries from BMZ or Panasonic

That looks like new tech, not something that's going to filter down to Ebikes YET. Probably at least a couple of years away if not more.
Extremely doubtful that any of the big manufacturers will make them retro to older bikes when they can make you buy a brand new bike to get the new wonder battery.
I did the math for volume (pi*r^2*h). In raw numbers, a 21700 cell should have 1.49 times the volume of an 18650 cell. If you take into account chemistry improvements over the last few years, I suspect the actual power density should be better than that over time. The press releases are also talking about factor of 4 (at least) more recharge cycles from the 21700 (2000+ instead of 300-600), though I don't know where that comes from. I would think that the 21700 cell should work very well for bicycle batteries. However it is larger, so the example in the link above of 40 cells of 18650 vs. 40 cells of 21700, the 21700 battery will be larger.
I was looking at another site and noticed a release regarding superior battery technology on the way for 2017, and was wondering if anyone knew which manufacturers were looking at these - and most importantly, if an offering will be made is size compatible with existing setups from the Bosch, Brose and Yamaha mid-motor units


The Triton by BMZ cells won't make it to the E-bikes until 2018.
As a materials scientist, I was super keen on these cells but as you know US market lags way behind the EU market (currently).
500Whr will be the baseline when it comes to battery sizes for 2017.