18650 battery

An 18650 battery or 1865 cell is a cylindrical lithium-ion battery common in electronic devices. The batteries measure 18 mm in diameter by 65 mm in length, giving them the name 18650. The battery comes in many nominal voltages depending on the specific chemistry used.

Panasonic first developed the 18650 battery in 1994 "when there was a growing need for ever smaller and lighter storage batteries that could be used for ever longer periods of time". They are now commonly used in power tools, electric bicycles, laptops, and electric vehicles.

Chemistry
18650 batteries are most commonly lithium-based.

By 2023, some sodium-ion variants were available in the 18mm x 65 mm cylindrical cell form factor as well.

Packs


18650 batteries are commonly used in packs, where a battery management system (BMS) is required, especially once cells age and perform differently. BMS boards balance the voltage of cells in series and protect against over- and under-discharge.

Products using 18650 cells
18650 battery cells are used in a wide variety of products from the 1990s through the 2020s, and is widely regarded as the most produced lithium-ion cell size. 18650/1865 cells are used in many laptop computer batteries, cordless power tools, many electric cars, electric scooters, most e-bikes, older portable powerbanks, electronic cigarettes, portable fans, and LED flashlights. Nominal voltage is 3.6-3.7 V.

In the electric automobile sector, they are used in the first three vehicles manufactured by Tesla, the first-generation Roadster (late 2000s), Model S (2012+), and the Model X (2015+).