Batteries :: essays research papers

BATTERIES There are many kinds of batteries which consist of different materials in order to produce an electric charge. Here are some of the most common batteries, what they consist of and how they work. Bichromate Cell (see picture # 1) A battery is a device which converts chemical energy into electrical energy. A battery usually consists of two or more cells connected in series or parallel, you can also have a single cell battery. All cells consist of a positive electrode, and a negative electrode. An electrolyte is a liquid substance capable of conducting electricity. In this substance one of the electrodes will react producing electrons, while the other will except electrons. When the electrodes are connected to a device to be powered, called a load, an electrical current flows. Batteries where the chemicals cannot be returned to their original form once the energy has been converted (that is, batteries that have been discharged) are called primary cells or voltaic cells. Batteries in which the chemicals can be returned to its original form by passing an electric current through them in the direction opposite that of normal cell operation are called secondary cells, rechargeable cells, storage cells, or accumulators. Dry Cell Battery(see picture # 2) This is the most common battery that people use today like Energizer or Duracle batteries. The most common form of a primary cell is the Leclanche cell, invented by a French chemist Georges Leclanche in the 1860s. The electrolyte for this battery consisted of a mixture of ammonium chloride and zinc chloride made into a paste. The negative electrode is zinc, and is the outside shell of the cell, and the positive electrode is a carbon rod that runs through the center of the cell. This rod is surrounded by a mixture of carbon and manganese dioxide. This battery produces about 1.5 volts. Another widely used primary cell is the zinc-mercuric-oxide cell, more commonly called a mercury battery. It can be made in the shape of a small flat disk and is used in this form in hearing aids, and electric wristwatches. The negative electrode consists of zinc, the positive electrode is of mercuric oxide, and the electrolyte is a solution of potassium hydroxide. The mercury battery produces about 1.34 volts. The fuel cell is another type of primary cell. It is unique in that the chemicals aren't contained within the cell but are supplied from outside of the cell.