How Batteries Work

Strictly speaking, the term battery refers to an array of (i.e. a battery of) electrochemical cells. A number of cells are connected or assembled into such an array to amplify the maximum possible performance of just a single cell. In common language, even a single cell is however refered to as a battery. The operation of a battery is best understood by looking more closely at what goes on inside an electrochemical cell.

Each cell is made of three vital components: a postive electrode, a negative electrode, and an electrolyte. A cell's ability to generate electricity is the result of two simultaneous chemical reactions: one at the positive electrode, and another at the negative electrode. The electrolyte serves as an insulator between the two electrodes to avoid an internal short circuit, and also permits a flow of charge-carrying particles between the electrodes. During discharge (i.e. normal use) of the battery, the two chemical reactions result in negatively charge electrons collecting at one electrode, and positively charged ions collecting at the other. When an external load, such as a lamp, is now connected to both electrodes, the electrons flow from the negative electrode (or cathode) to the positve electrode (or anode) doing useful work (e.g. making our lamp light up).

A lot of research has gone into which are best materials or chemicals to use as electrodes and electrolytes, and numerous effective combinations have been discovered. These alternatives are called cell chemistries, and give rise to the labels such as "Alkaline" or "Lithium" that are commonly used today to distinguish between batteries.

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