18650 battery

For other uses, see 18650 (disambiguation).

An 18650 battery^[1] or 1865 cell^[2] is a cylindrical battery size (often lithium-ion battery or sodium ion battery) common in electronic devices. The batteries measure 18 mm (0.71 in) in diameter by 65 mm (2.56 in) in length, giving them the name 18650.^[3] The battery comes in many nominal voltages depending on the specific chemistry used.

• 18650 battery
• 1865 cell

Panasonic 18650 batteries inside a laptop. Each cell has a capacity of 2450 mAh.
Type	Power source
Working principle‍	Electrochemical reactions, Electromotive force
First production	1994
Pin names	Anode and Cathode
Electronic symbol

Sony developed the 18650 in 1991,^[4][5] though Panasonic claims to have done so in 1994.^[6] They are now commonly used in power tools, electric bicycles, laptops, and electric vehicles.^[7]

Chemistry

18650 batteries are most commonly lithium-based.^{[citation needed]}

NMC811 can be doped with ZrO₂ to produce a cathode for these batteries^[8]

By 2023, some sodium-ion variants were available in the 18mm x 65 mm cylindrical cell form factor as well.^{[9][better source needed]}

In 2024, a potassium-ion variant was unveiled in the 18650 format that utilizes a proprietary 4V Potassium Prussian White cathode and a commercially available graphite anode.^[10]

Packs

A generic BMS for 4 series lithium-ion cells ('4s BMS')

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 are widely regarded as the most produced lithium-ion cell size.^[11] 18650/1865 cells are used in many laptop computer batteries, cordless power tools, many electric cars, electric scooters,^[12] most e-bikes, older portable powerbanks, electronic cigarettes,^[13][14] portable fans, and LED flashlights. Nominal voltage is 3.6-3.7 V.^[15][7]

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+).^[16]

See also

• List of battery sizes