A battery is a device that stores electrical energy and converts it into usable power. It consists of one or more electrochemical cells, which generate electricity through chemical reactions. Common types of batteries include alkaline, lithium-ion, and lead-acid, each with specific applications and characteristics. Batteries are widely used in everyday items, such as remote controls, smartphones, and electric vehicles. They provide a portable source of energy, making it possible to power devices without being connected to an electrical outlet. The efficiency and lifespan of a battery depend on its design and usage conditions.