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Adry cell is a type ofelectric 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 toleakage.
The dry cell was developed in 1886 by the German scientistCarl Gassner, after the development of wetzinc–carbon batteries byGeorges Leclanché in 1866. A type of dry cell was also developed by the Japanese inventorSakizō Yai in 1887.
Many experimenters tried to immobilize the electrolyte of an electrochemical cell to make it more convenient to use. TheZamboni 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.[1]
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 withPlaster of Paris to create a paste, with a small amount ofzinc chloride added in to extend the shelf life. Themanganese 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 obtainedU.S. patent 373,064 for the same device.[2] A dry-battery was invented in Japan during theMeiji Era in 1887. The inventor wasSakizō Yai.[3] However, Yai didn't have enough money to file the patent,[4] the first patent holder of a battery in Japan was not Yai, butTakahashi Ichisaburo.Wilhelm Hellesen also invented a dry-battery in 1887 and obtainedU.S. patent 439,151 in 1890.[3]
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 theNational Carbon Company in 1896.[5] 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. It was the first convenient battery for the masses and made portable electrical devices practical.
Thezinc–carbon cell (as it came to be known) is still manufactured today.
A dry cell uses a pasteelectrolyte, with only enoughmoisture to allow current to flow. Unlike awet cell, a dry cell can operate in any orientation without spilling, as it contains no free liquid, making it suitable for portable equipment. By comparison, the first wet cells were typically fragile glass containers with lead rods hanging from the open top and needed careful handling to avoidspillage.Lead–acid batteries did not achieve the safety and portability of the dry cell until the development of thegel battery. Wet cells have continued to be used for high-drain applications, such as startinginternal combustion engines, because inhibiting the electrolyte flow tends to reduce the current capability.
A common dry cell is thezinc–carbon cell, sometimes called the dryLeclanché cell, with a nominal voltage of 1.5volts, the same as thealkaline cell (since both use the samezinc–manganese dioxide combination).
A standard dry cell comprises azincanode, usually in the form of a cylindrical pot, with acarboncathode in the form of a central rod. Theelectrolyte isammonium chloride in the form of a paste next to the zinc anode. The remaining space between the electrolyte and carbon cathode is taken up by a second paste consisting ofammonium chloride andmanganese dioxide, the latter acting as adepolariser. In some designs, often marketed as "heavy duty", the ammonium chloride is replaced withzinc chloride.
Primary cells are notrechargeable and are generally disposed of after the cell's internal reaction has consumed the reactive starting chemicals.
Secondary cells are rechargeable, and may be reused multiple times.
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