Voltaic pile

The voltaic pile or column Volta is a 1799/1800 developed by Alessandro Volta and presented to the Royal Society in London to the public in 1800 arrangement, which had as a precursor of today's batteries in the 19th century a great importance as a source of power. It consists of many layered copper and zinc plates, between which there are in a certain regular sequence electrolyte-saturated cardboard or leather pieces. Instead of copper, silver and zinc instead of tin also was used.

A single element of the column is called voltaic Volta element. It comprises for example a copper foil, an electrolyte layer and a zinc foil. It provides only a low voltage, which is why many such elements are stacked in the column. This results in the stacking sequence of copper, electrolyte, zinc, copper, zinc electrolyte and again, that is, copper and zinc alternate and the electrolyte is in this example always between copper (bottom) and zinc (above).

Importance

The voltaic pile can be classified as one of the greatest inventions of all time, as they were first viable continuous power source, the study of electricity made ​​it possible - long before the invention of the electric generator. Thus, the voltaic pile has both electrical engineering and electronics and many other technical areas, such as electroplating, paved the way. Especially intensive research regarding the therapeutic use of the direct current ( galvanic current, galvanotherapy ) were immediately after the publication of Galvani - voltaic performed column by numerous doctors, such as John Wesley, England, Bischoff, CHE, Jena 1801 ( De Usu Galvanisimi in Arte Medica ), Grapengiesser, Martens, Berlin 1803, Golding Bird, London 1840, Duchenne, Paris 1855, or Remak, Berlin, 1858. the voltaic pile was the first major battery and enabled the discovery of electrolysis and thus the initial presentation of many noble elements, especially the metals sodium, potassium, barium, strontium, calcium and magnesium by Humphry Davy in 1807 and 1808. the first attempts at communication by the electric telegraph were enabled by the invention Voltas possible.

Application in the art

With the help of the voltaic pile or successors and thus arcs produced electric lighting was implemented with arc lamps. Arc lamps are the oldest electric light sources. Johann Samuel Halle ( 1792) and Briton Humphry Davy (1802 ) have observed the effect of the arc and used for illumination. It brass or graphite electrodes were used, the graphite electrodes burned down relatively quickly.

One of the first applications in the marine engineering were performed by Moritz Hermann von Jacobi, of using a lying voltaic pile and a developed and built by him electric motor powered the first electric boat in Saint Petersburg in 1839. The experiments were carried out on St. Petersburg's canals and the Neva and approved by a state commission.

Operation

The voltaic pile is a set of series-connected galvanic cells. At the negative pole, the anode is here, since the oxidation takes place, the less noble metal goes into solution: The zinc plate dissolves: Each zinc atom which goes as zinc ion in solution, are two electrons; there arises in the zinc electrode, a surplus of electrons, which is why it forms the negative pole.

On the positive electrode, the cathode, since the reduction takes place, a plurality of reactions are possible. If it is the copper plates, which have not been polished, they are covered with an oxide layer. Then, it performs the reduction. This may also take place when the copper is in solution due to the presence of atmospheric oxygen.

But the voltaic pile works even if polished copper or silver are used as the electrodes, that is, when no copper or silver ions are present. Then, oxygen is reduced from the air on the copper or silver: Using, (e.g., salt water), an acid (such as acetic or dilute sulfuric acid or hydrochloric acid ) so to reduce hydrogen ions in place of a neutral electrolyte on the copper or silver. Hydrogen evolution takes place not only at the zinc electrode, since hydrogen has a significantly greater on zinc Circuit as copper or silver.

A major disadvantage of voltaic pile is due to the vertical structure in the form of a column. The weight of the stacked metal plates between the metal plates inserted and soaked with electrolyte soft cardboard or leather pieces are pressed together. Thereby, the liquid electrolyte, especially in the lower region of the column, pressed outwards and reduces the battery capacity of the entire arrangement. The technical development of the voltaic pile from 1802 which avoids this drawback, represents the trough battery by William Cruickshank