The secret of the 18650 lithium battery you don't know -part 1

A history of 18650 batteries?

18650 is the originator of the lithium-ion battery, a standard lithium-ion battery model that Japan SONY Company set in order to save cost. Among them, 18 means diameter 18mm, 65 means length is 65mm, 0 means cylindrical battery. The common 18650 battery is divided into a lithium-ion battery and a lithium iron phosphate battery. The lithium-ion battery voltage is 3.7V, the charge cut-off voltage is 4.2v, the lithium iron phosphate battery has a nominal voltage of 3.2V, the charge cut-off voltage is 3.6v, the capacity is usually 1200mAh-3350mAh, and the common capacity is 2200mAh-2600mAh.

The 18650 means 18 mm in diameter and 65 mm in length. The model number of the No. 5 battery is 14,500, 14 mm in diameter and 50 mm in length. Generally, the 18650 rechargeable battery is used in the industry, and the common ones are used in notebook batteries and high-end flashlights. According to the type of battery can be divided into 18650 lithium ion, 18650 lithium iron phosphate, 18650 nickel hydrogen (rare), the common 18650 is lithium ion.

What is a lithium battery?

Lithium-Ion Battery: Lithium-ion batteries are widely used because of their lightweight, large capacity, and no memory effect. Many digital devices use lithium-ion batteries as power supplies, despite their prices are relatively expensive. Lithium-ion batteries have a high energy density, and their capacity is 1.5 to 2 times that of nickel-hydrogen batteries of the same weight and has a very low self-discharge rate. In addition, the lithium-ion battery has almost no "memory effect" and does not contain toxic substances, which is also an important reason for its wide application.

In addition, please note that the external lithium battery is generally marked with English 4.2V lithium-ion battery (lithium battery) or 4.2V lithium secondary battery (lithium secondary battery), 4.2V lithium-ion rechargeable battery (charged lithium battery), so users who purchase the battery must look at the signs on the outside of the battery block to prevent the cadmium-nickel and nickel hydride batteries from being mistaken for lithium batteries because they do not see the battery type.