Dry cell
A dry cell is a type of electric battery, commonly used for portable electrical devices. Unlike wet cell batteries, which have a liquid electrolyte, dry cells use an electrolyte in the form of a paste, and are thus less susceptible to leakage. The dry cell was developed in 1886 by the German scientist Carl Gassner, after development of wet zinc–carbon batteries by Georges Leclanché in 1866. A type of dry cell was also developed by the Japanese Sakizō Yai in 1887. Many experimenters tried to immobilize the electrolyte of an electrochemical cell to make it more convenient to use. The Zamboni pile of 1812 is a high-voltage dry battery but capable of delivering only minute currents. Various experiments were made with cellulose, sawdust, spun glass, asbestos fibers, and gelatine. In 1886, Carl Gassner obtained a German patent (No. 37,758) on a variant of the (wet) Leclanché cell, which came to be known as the dry cell because it did not have a free liquid electrolyte. Instead, the ammonium chloride was mixed with Plaster of Paris to create a paste, with a small amount of zinc chloride added in to extend the shelf life. The manganese dioxide cathode was dipped in this paste, and both were sealed in a zinc shell, which also acts as the anode. In November 1887, he obtained for the same device. A dry-battery was invented in Japan during the Meiji Era in 1887. The inventor was Sakizō Yai. However, Yai didn't have enough money to file the patent, the first patent holder of a battery in Japan was not Yai, but Takahashi Ichisaburo. Wilhelm Hellesen also invented a dry-battery and obtained in 1890. Unlike previous wet cells, Gassner's dry cell is more solid, does not require maintenance, does not spill, and can be used in any orientation. It provides a potential of 1.5 volts. The first mass-produced model was the Columbia dry cell, first marketed by the National Carbon Company in 1896. The NCC improved Gassner's model by replacing the plaster of Paris with coiled cardboard, an innovation that leaves more space for the cathode and makes the battery easier to assemble.