hey @Shirtboy James, Batteries are an integral part of our everyday lives, if the shops stop stocking batteries for what ever reason we will still need them.
I think it would make a really good science workshop, the science is very simple to get your head round, just need two electrodes that should be different metals or a metal and carbon, and some acid or other suitable electrolyte. Different combinations of materials will define the performance characteristics of the cell. Put the device in a circuit and the electrons will flow.
Other very useful variations on the theme using almost the same kit would be devices for electroplating (could be good for jewellery makers) and also electrolysis (good for making hydrogen and oxygen)