Batteries are like piggy banks. Cell is the basic unit of energy. Two or more cells connected together is called battery. They are our energy storehouse. A Battery converts chemical energy into electrical energy. They are mobile or portable source of power. They are used in alarm clocks, watches, remotes, smartphones, hearing aids, etc. They can be compared to a tin of chemicals with two terminals, negative terminal or the cathode and a positive terminal or a anode.
As chemical reactions aggregate electrons at the anode, the cathode devoid of electrons, gets positively charged.
Connecting the anode and the cathode creates the flow of electricity—lighting an LED or moving a toy.
Batteries can be classified as Primary batteries or secondary:
Primary batteries are disposable batteries that produce electricity immediately. Once they get drained, they cannot be recharged. They are cheap, safe to use and easily available. They are commonly used in constructing hobby projects.
Secondary batteries are rechargeable. They require another power source to charge them up. They can be charged many times during their lifespan.
Batteries are also categorized according to their shape, size, terminal layout, voltage and chemical reactions.