What is an 18500 lithium battery?

1.What is an 18500 lithium battery?

The 18500 battery is a widely used cylindrical lithium battery, commonly employed in electronic cigarettes, toys, security systems, and automotive electronics.

2.Basic introduction to the 18500 lithium battery:

In China, there are many companies with mature battery cell technologies, offering products with stable performance. The naming convention follows the pattern of 18650, where the battery’s diameter is 18mm and length is 65mm. Similarly, the 18500 battery has a diameter of 18mm and a length of 50mm, and it belongs to the cylindrical type of battery.

3.Parameters of the 18500 lithium battery:

Voltage: 3.6V (conventional general-purpose battery for low-power electronic devices, maximum 1C discharge; discharge conditions can be adjusted as needed)
Charging parameters: 4.2V
Minimum discharge termination voltage: typically 2.75V
Maximum charging termination voltage: 4.20V
Capacity: Currently up to 1900mAh for 3.6V lithium cobalt oxide (LiCoO2) technology
Diameter: 18±0.2mm
Height: 50±0.3mm

4.Common configurations of the 18500 lithium battery:

Configuration: 4S2P
Nominal voltage: 14.8V
Output voltage range: 10~16.8V
Nominal capacity: 3000mAh
Standard continuous discharge current: 0.2C
Maximum continuous discharge current: 1C
Operating temperature: Charging: 045°C, Discharging: -2060°C
Product dimensions: MAX 355483mm
Internal resistance of finished product: ≤250mΩ
Wire type: National standard wire UL1007/18#, wire length 150mm

5.Protection parameters of the 18500 lithium battery:

Overcharge protection voltage: Per series 4.25±0.025V
Over-discharge protection voltage: 2.5±0.08V
Overcurrent value: 4~8A

6.Selection of chargers for 18500 lithium batteries:

Standard charging: Initially charge the battery at a constant current of 0.5C5A (1.5A) until reaching 4.2V, then switch to constant voltage charging at 4.2V until the charging current gradually decreases to 0.01C5A. Charging time is approximately 3 hours. Charging the battery within 0~45°C should not cause permanent damage.
Standard discharging: After the fully charged 18500 battery is left for 30 minutes at an ambient temperature of 20±5°C, discharge it at a constant current of 0.2C5A until reaching 6.0V. Discharge time is approximately 5 hours. Therefore, a 4.2V/1A lithium battery charger is suitable for this purpose.