It's the other way around.
Bigger units have the space for smarter chips onboard the battery module, especially in laptop battery designs you need balancing chips to make sure no individual cells are getting out of sync with the others.

The NITs have no ICs in the batteries. There's mechanical thermal and overcurrent protection in the battery. (often missing or defective on third party batteries since it's a cost saving the consumer wont notice with their eyes until it all goes boom). The charging logic is in the tablet. There is a resistor in the battery for signaling the design capacity. The battery meter software uses that information for estimating remaining capacity and presenting battery low warning. It seems to ultimately make shutdown decision based on voltage though, not on calculated remaining capacity. The same applies when charging, it charges the battery to full (except if you use a "Special" charger, then it takes it up to slightly less than full and holds it there). Full is detected by charge current and battery voltage. It's essentially the only sensible way of charging Li-Ion (and Li-Polymer).