The 18650 is the originator of the lithium ion battery -- a standard lithium ion battery model set by the Japanese SONY company in order to save costs, of which 18 represents a diameter of 18mm, 65 represents a length of 65mm, and 0 represents a cylindrical battery 18650 common batteries are divided into lithium-ion batteries, lithium iron phosphate batteries, lithium-ion battery voltage is nominal voltage of 3.