An 18650 battery or 1865 cell is a cylindrical battery size (often lithium-ion battery or sodium ion battery) common in electronic devices. The batteries measure in diameter by in length, giving them the name 18650. The battery comes in many nominal voltages depending on the specific chemistry used.
Sony developed the 18650 in 1991,O. Kazunori and M. Yokokawa, Cycle performance of lithium ion rechargeable battery, 10th Int. Seminar of Primary and Secondary Battery Technology Applications, 1-4 Mar. 1993, Deerfield Beach, FL, USA, Florida Educational Seminars, Boca Raton, FL. though Panasonic claims to have done so in 1994. They are commonly used in power tools, electric bicycles, laptops, and electric vehicles.
Chemistry The 18650 designation refers only to the physical dimensions of the cell and does not specify its electrochemistry. Most 18650 cells are lithium-ion batteries and have been manufactured using several cathode chemistries, including lithium cobalt oxide (LCO),Electronic transport properties in lithium cobalt oxide battery electrode material studied in ion-gated transistor configuration manganese dioxide (LMO Lithium ion manganese oxide battery), lithium nickel manganese cobalt oxide (NMC),NMC Battery vs. LCO Battery: What’s the Difference? lithium nickel cobalt aluminum oxide (NCA),Fast–charging lithium–ion batteries: Review on enhancing lithium nickel cobalt aluminum oxide cathodes with additives and lithium iron phosphate (LFP Lithium iron phosphate battery). Different chemistries offer trade-offs between energy density, power output, cycle life, cost, and thermal stability.
NCA and NMC chemistries have been widely used in high-energy applications such as electric vehicles and power tools, while LFP cells are valued for their long cycle life and improved thermal stability.
By the early 2020s, manufacturers had also introduced sodium-ion cells in the 18650 form factor. In 2024, a potassium-ion battery in the 18650 format was announced, demonstrating that the form factor can accommodate emerging battery chemistries in addition to lithium-ion technologies.
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 are widely regarded as the most produced lithium-ion cell size. 18650 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 .
In the electric vehicle sector, they are used in three vehicles manufactured by Tesla: the first-generation Roadster (2008-2012), Model S (2012-2026), and the Model X (2015-2026).
See also
List of battery sizes
References