Battery

A battery (also called a cell) is a device that stores chemical energy and converts it into electrical current when a circuit is closed. It consists of one or more connected units, each containing two electrodes—a positive terminal (cathode) and a negative terminal (anode)—and an electrolyte, through which ions can move.

When a battery is connected to a device, a chemical reaction within the cell causes electrons to be released at the negative terminal and flow through the circuit to the positive terminal. This flow of electrons is what powers lights, motors, and other electrical devices. Key specifications include voltage, storage capacity (typically measured in ampere-hours), and the number of charge cycles a rechargeable battery can undergo.

Types

Batteries are divided into two main categories. Primary batteries are used once and then discarded, such as those in watches and remote controls. Secondary batteries are rechargeable and are found in mobile phones, laptop computers, and electric vehicles. Common examples include alkaline batteries, lead-acid batteries used in ordinary vehicles, and lithium-ion batteries.

Brief history

The earliest battery to produce a steady electric current is attributed to Italian scientist Alessandro Volta, who in the early 19th century demonstrated a device consisting of alternating discs of different metals separated by a salt solution. This is the origin of the term for battery in several languages (for example, Italian "

Uses and challenges

Batteries are fundamental to portable devices and electric vehicles, and are also used to store energy from solar and wind power. Major challenges include the extraction of materials such as lithium and cobalt, which have environmental and social impacts from mining, the risk of fire and explosion if a battery ruptures, and the need for a recycling system for spent batteries before they enter landfills.