Battery

A battery is a device that converts potential chemical energy into electrical energy through irreversible or reversible electrochemical reactions. Modern batteries consist of one or more cells, each containing two terminals (anode and cathode) separated by a chemical medium called an electrolyte, which facilitates the flow of ions and creates electrical current.

Batteries power everything from smartphones to electric vehicles, making them essential to contemporary life. The earliest batteries, like the Voltaic pile, were invented in the early 1800s. Today's common types include alkaline batteries (single-use), lithium-ion batteries (rechargeable, dominant in electronics), and lead-acid batteries (found in cars).

A battery's capacity is measured in units like milliamp-hours (mAh) or watt-hours (Wh), indicating how long it can deliver current. Efficiency varies by chemistry and discharge rate. The search for better batteries—higher capacity, faster charging, longer lifespan, safer materials—is central to Renewable energy and transportation technology.

Beyond portable power sources, "battery" also refers to a coordinated group of artillery pieces or, in law, a form of assault. The term itself derives from military formations.

Related

Electrolyte, Electrochemistry, Energy storage, Renewable energy, Charging (electrical), Electrical current