Batteries are compact energy storage devices that power countless everyday electronics. They come in multiple types and sizes, from common AA and AAA batteries used in household items to lithium-ion batteries found in smartphones and laptops, and lead-acid batteries for vehicles and backup power systems. Batteries convert stored chemical energy into electrical energy, allowing devices to operate without a direct power source.

The versatility of batteries makes them indispensable in modern life. For instance, alkaline batteries are affordable, disposable options for low-power devices like clocks and flashlights, while rechargeable batteries, such as lithium-ion, are used for devices requiring frequent charging. Some batteries, like nickel-cadmium and nickel-metal hydride, offer longer life and higher durability, ideal for power tools and medical equipment. Batteries are available in various capacities to suit specific energy demands, ensuring reliable performance across applications.