Voltage is the potential difference between the terminals of the battery,and this potential difference is created by the work that the chemicals inside the battery had done.
Also, work done is determined by the force between the charges and the distance through which they are separated. That is, work done by the battery is given by the Force (between charges of both terminals) multiplied (or integrated) with the distance of separation.
Now, if I take a 1.5 volt cell (with its electrons concentrated at the negative terminal) and pull it and elongate it (supposing it still works) and move the electrons away from the positive terminal, with my external force, then will my work get stored as potential energy and hence increase the voltage of the cell?