The Bagdad Battery
In 1936 near Bagdad, workers uncovered an ancient tomb while constructing a new railway for the city. Analyzing the relics, archeologists were able to identify the creators of the artifacts as the Parhian Empire (The Parthians ruled over the western half of Khorasan region in northeastern Iran.)
In 1938, Dr. Wilhelm Konig, a German archeologist, identified the clay jar as a possible battery. The jar was sealed with pitch at the top, an iron rod in the center, surrounded by a cylinder-shaped tube made from wrapped copper sheets. The height was approximately 14 cm, and the copper tube had somewhere around 4 cm in diameter and 12 cm in length. The jars have been named the "Baghdad Batteries".
The replicas made showed that when filled with a weak acidic solution like vinegar or lime juice, produced a current between 1.5 and 2 volts. It is believed that connecting one or more of these early batteries in series, could have been used to electroplate gold onto silver objects.
This 2000 year old jar would make the first battery invented and documented in history. There may have been even earlier similar technologies, like the Sumerian vases made of copper, but electroplated with silver, dating back to 2500 BC, but no evidence of Sumerian batteries has been found to date.
The voltaic pile (modern battery invention)
The first modern battery began its development in 1780 with Luigi Galvani while he was dissecting a frog fixed to a brass hook. When he touched the frog’s leg with his iron scalpel, the leg twitched. He believed that the moving leg was produced by the animal’s energy, and called it “animal electricity”.
A friend of Galvani, Alessandro Volta, started his own experiments trying to find another explication for the “leg twitch”. After he repeated Galvani's experiments many times and different materials he came to the conclusion that it was the two dissimilar metals, not the frog’s leg that produced the electricity. The frog’s leg was just a sign of presence of the electricity.
In 1980 Volta published the details of the first true battery, which came to be known as the voltaic pile. Consisting of discs of copper and zinc piled on top of each other and separated by an electrolyte solution (a layer of cloth or cardboard soaked in brine). Because of his invention he received recognition by naming the standard unit of electric potential as volt.