Battery charge times
It doesn't work that way.  One of these two issues will get you:

You "spilt" the original batteries into smaller batteries, maintaining the overall battery capacity.  The smaller batteries now have lower capacity and lower maximum allowed charging current.  If a original battery can be charged at 1 mAh/minute, then a battery resulting from a 1:2 split could only be charged at &frac12; mAh/minute.

With the batteries split to conserve overall capacity, a larger fraction of the whole volume would be taken up by interrconnects, so the overall battery pack would now be larger and a little heavier.

You use more of the same size batteries.  Each can now be charged at the original rate, but the battery pack has become proportionally heavier and larger.

The cell phone maker has already picked a tradeoff between size and weight on one side and longevity of charge on the other.  For the same battery technology, you can't cheat this tradeoff.  By adding more batteries, you increase longevity of charge, but you can't get away from the proportionally larger size and weight of the resulting battery pack.



If it were really so simple, they'd be doing it.