Chemical limit of the materials. If you go out to buy battery bigger than 12v, for example 24v, then you will see that it is actually made of 2 12v or may be ev

Chemical limit of the materials. If you go out to buy battery bigger than 12v, for example 24v, then you will see that it is actually made of 2 12v or may be even 16 1.5v, depends on what material they use to make a battery. I have asked your question about Tesla and low voltage batteries to my friend who was studying as Physics Teaching, he explained me these things.