Most would say that it was invented by Allesandro Volta in the very early 1800's. Volta discovered the fact that within a given object the voltage and charge are proportional, and this led to his “law of capacitance”. This work with capacitance and voltage caused the unit of potential difference to be named after Volta. After this Volta began studying something that a physicist named Galvani had discovered. Galvani had connected two different metals with a frogs leg, and noticed that current could flow through it. Volta was the one who recognized that the frog leg was a conductor of the electricity, and that the same phenomenon could be repeated without using the frog leg, and that the current could be sustained. Volta created a new design for this that was known as the voltaic pile. This pile was constructed using copper and zinc disks, acidsoaked cardboard pieces, hydrogen, and sulfuric acid. The copper and zinc disks were stacked on top of each other with a piece of acid soaked cardboard in between each one. The battery created a potential difference in the circuit and made current flow consistently through the circuit. This was the first real battery, and created the potential for basically all future discoveries in the field of electronics. however there has been another battery found that was made of a clay pot with an iron rod sticking out and it was filled with an acidic fluid. This was made around 350 B.C.E.