How batteries work


All batteries — whether early sealed dry cells or alkaline batteries of the mid-20th century or more contemporary lithium batteries — have the same purpose and share many of the same characteristics. Batteries store chemical energy which is then converted into electrical energy used to power a device. Indeed, the need for portable power continues to grow in the modern world.

A battery consists of two different electrodes, either metal or metallic compounds. These are connected by an ion-conducting solution known as an electrolyte. Ions are an atom or molecule that has an electric charge, positive or negative. Basic to all batteries is that one electrode attracts electrons more strongly than the other, the cathode and anode, respectively. The difference in the attraction is the voltage of the cell. In most batteries the anode is zinc and the cathode is manganese dioxide. When the two electrodes are connected by an electrolyte, chemical reactions can occur between the electrodes and the electrolyte. When a wire is externally connected to the two electrodes, the manganese dioxide's stronger attraction for electrons pulls the electrons from the zinc electrode, through the wire, to the manganese dioxide electrode. This process produces a flow of current to power devices.

The processes by which batteries work and the basic construction has not changed in over a hundred years. New research is aimed at producing smaller, longer-lasting batteries that produce more energy to power ever smaller electronic devices: digital cameras, telephones, and portable computers. One obvious and dramatic change in batteries is size. The Columbia dry cell was six inches long; modern batteries for hearing aids and watches measure are smaller than 1/4 inch by 1/8 inch.


 

next | back | home

 

History of the battery | Columbia dry cell | Innovation meets industry and location
How batteries work | Landmark designation and acknowledgments

Copyright ©2005 American Chemical Society. All Rights Reserved. 1155 16th Street NW, Washington DC 20036
202-872-4600, 800-227-5558