Inspired by frogs, the voltaic stack battery was born, the interesting story behind the invention of the voltaic stack

Today, we need to use a variety of batteries in our lives, ranging from new energy vehicles, such as Tesla and BYD. The starting batteries of various vehicles, the smartphones, notebook computers, portable electronic products we use, etc., are inseparable from the invention of batteries.

Some are disposable, such as AAA batteries. There are also rechargeable lithium-ion, nickel-chromium batteries that can be discharged multiple times.

So, what is a battery? It is actually a device that generates electricity through a chemical reaction. 1748 - Benjamin Franklin coined the term "battery" to describe an electrified sheet of glass.

Luigi Galvani was an Italian physician, physicist, and biologist. In 1780, Galvani was peeling a frog on a table. He and his wife had been experimenting with static electricity by rubbing the frog's skin. Galvani's assistant touched the frog's bare sciatic nerve with a charged metal scalpel. Just then, they saw sparks, and the legs of the dead frog seemed to be alive. This was one of the first attempts at bioelectricity research, and he discovered animal electricity, recognized as a pioneer of bioelectromagnetics.

A friend of Galvani's, physicist Alessandro Volta (aka Volta) disagreed with Galvani's theory of bioelectrical effects, arguing that contractions depended on the metal wires used to connect nerves and muscles. Volta believed that animal electricity was a type of metallic electricity, caused by the interaction between the two metals involved in the experiment.

Alessandro Volta was born in Como, Italy in 1745. At the age of 29, he became a professor of physics at Como Royal School, and while working at Como, he studied and experimented with air electricity by igniting electrostatic sparks, one of his inventions, the electrophoresis apparatus. At the age of 34, he became a professor of physics at the University of Pavia.

He set out to prove that electricity did not come from animal tissue, but was produced by the contact of dissimilar metals, brass and iron, in a humid environment. Ironically, both scientists were right.

Volta tested this hypothesis through experiments, and in 1800, Volta invented the real battery, which was later called the Voltaic pile. A voltaic stack consists of pairs of copper and zinc discs stacked on top of each other, separated by a layer of cloth or cardboard soaked in salt water (i.e. electrolyte). Unlike the Leiden jar, the voltaic pile produces a constant power and a steady current, and loses little charge when left for long periods of time when not in use, although his early models could not produce a voltage strong enough to generate a spark. He experimented with various metals and found that zinc and silver worked best. Volta coined the term "current" to refer to the direct current produced by chemical action.

Another problem with voltaic batteries is their short battery life (up to an hour), which is caused by two phenomena. The first is that the resulting current electrolyzes the electrolyte solution, causing a film of hydrogen bubbles to form on the copper, thereby steadily increasing the internal resistance of the battery (this effect, called polarization, is counteracted in modern batteries by additional measures). The other is a phenomenon called localization, where tiny short circuits form around impurities in zinc, causing zinc to degrade. The latter problem was solved in 1835 by the British inventor William Sturgeon, who found that amalgamated zinc, whose surface had been treated with some mercury, would not be affected by local action.

Despite its flaws, voltaic batteries provided a more stable current than Leiden jars and enabled many new experiments and discoveries. It also laid the foundation for modern battery technology.

An English professor of chemistry named John Frederick Daniel, who found a solution to the problem of hydrogen bubbles in a voltaic pile, invented the Daniel battery in 1836, which consisted of a cell filled with a copper sulfate solution. consists of a copper pot in which an unglazed earthenware vessel filled with sulfuric acid and a zinc electrode are immersed. The pottery barrier is porous, which allows the passage of ions but prevents the solution from mixing.

The Daniel battery was a major improvement over the voltaic battery and became a practical battery. It provides longer and more reliable current than voltaic batteries. It's also safer and less corrosive, and it operates on about 1.1 volts. It quickly became the industry standard for battery usage, especially in the telegraph network.

In 1859, French inventor Gaston Plant developed a practical rechargeable lead-acid battery. This type of battery is currently mainly used in cars as starting batteries.