18650 is the originator of lithium-ion batteries - Japan's SONY company set a standard lithium-ion battery model in order to save costs, where 18 indicates that the diameter is 18mm, 65 indicates that the length is 65mm, and 0 indicates that the cylindrical battery. Common rechargeable 18650 lithium battery, the voltage is standard 3.6 or 3.7v, fully charged when 4.2v, which has little to do with the power (capacity), 18650 battery mainstream capacity from 1800mAh to 2600mAh, (18650 power battery capacity is more than 2200~2600mAh), The mainstream capacity even has a standard 3500 or 4000mAh above.
The production of 18650 lithium batteries requires a protection line to prevent the battery from being overcharged and resulting in discharge. Of course, this is necessary for lithium batteries, which is also a disadvantage of lithium batteries, because the materials used in lithium batteries are basically lithium cobalt acid materials, and lithium cobalt acid lithium batteries can not be large current discharge, and the safety is poor.
Compared with the general battery production, 18650 lithium batteries have high requirements for production conditions, which undoubtedly increases the production cost.