An electric battery is a device consisting of two or more electrochemical cellsthat convert stored chemical energy into electrical energy. Each cell has a positive terminal, or cathode, and a negative terminal, or anode.
Batteries convert chemical energy directly to electrical energy. A battery consists of some number of voltaic cells. Each cell consists of two half-cells connected in series by a conductive electrolyte containing anions and cations.
Batteries are classified into primary and secondary forms.
a) Primary batteries irreversibly transform chemical energy to electrical energy. When the supply of reactants is exhausted, energy cannot be readily restored to the battery.
- Zinc-Carbon Batteries
- Alkaline Batteries
b) Secondary batteries can be recharged; that is, they can have their chemical reactions reversed by supplying electrical energy to the cell, approximately restoring their original composition.
- Lead-Acid Batteries
- Sealed Valve Regulated Lead-Acid Batteries
- Gel batteries (or "gel cell") use a semi-solid electrolyte.
- Absorbed Glass Mat (AGM) batteries absorb the electrolyte in a special fiberglass matting.