Battery Cells
- PDF / 2,286,446 Bytes
- 4 Pages / 576 x 777.6 pts Page_size
- 48 Downloads / 192 Views
Battery Cells
a disk of zinc (the anode), then a second disk of silver, and so on. The voltage of the battery could be increased by adding more layers; after connecting a wire from the top We are accustomed to bringing compact rials are depleted, the battery can no longer disk of silver to the bottom disk of zinc, an and portable energy sources along with us electrical current would flow. produce electricity. A battery that cannot to power all our technological devices. be recharged is called a primary battery; in a Another form of the same battery was These energy sources—batteries—are secondary battery, the active materials can called a "crown of cups" in which the indigrowing smaller and smaller, with inbe regenerated, allowing it to be used over vidual cells were assembled in separate creased power outputs and increased lifeand over again. vessels. Other variations of the "voltaic times. pile" used tin instead of zinc, or copper inCrude primary batteries may have been A battery is a device that converts chemistead of silver; sometimes vinegar was used thousands of years ago. From about cal energy directly into electrical energy. As 250 B.C., the Parthians possibly used bat- used as the electrolyte. Volta's battery caused a revolution in science because, for such, batteries are inherently highteries to gold-plate some of their jewelry. efficiency devices (about 60%), while methe first time ever, relatively large amounts The commonly recognized discovery of of electric current became available for use. chanical conversion devices—such as the electrical battery, however, took place internal combustion engines—must burn a in Italy in the 1790s with the work of AlesIn following years, many other scientists fuel to expand a gas to do work, resulting sandro Volta, a professor of natural philosexperimented with variations on the volin efficiencies of 40% or less. ophy at the University of Pavia. Volta put taic pile, many of which were attempts to the difference in potential of metals in con- reduce the drastic corrosion that occurred Within a battery the constituent chemitact with an electrolyte. In 1800 he wrote a on the electrodes when the battery was not cals are arranged so that the electrons repaper describing his "Volta pile," consistin use. As early as a year after Volta's first leased from one material flow through an ing of a disk of silver (the cathode), upon description of his battery, it was discovered external circuit to another part. This chemiwhich he stacked a disk of paper, doth, or cal reaction consumes the active materials that coating the electrodes with mercury hide soaked in a salt solution (electrolyte), within a battery cell and, when such matehelped reduce the corrosion and thus increase the shelf life of batteries. In 1836 in England, the chemist John Daniell made a great improvement to the voltaic pile by reducing the severe polarization that occurred in the electrodes. He treated his zinc cathodes with zinc sulfate, and his copper anodes with copper sulfate, then placed a porous earthenware
Data Loading...
