14.8V 20Ah 18650 Lithium Battery for Security Communication

Cell model: 18650/3.7V/2.5Ah
Battery specification: 18650-4S8P/14.8V/20Ah
Nominal voltage: 14.8V
Nominal capacity: 20Ah
Charging voltage: 16.8V
Charging current: ≤4A
Discharge current: 4A
Instant discharge current: 5A
Discharge cut-off voltage: 12.0V
Internal resistance of finished product: ≤250mΩ
Battery weight: 1.6Kg
Product size: 170*90*78mm (Max)
Charging temperature: 0～45℃
Discharge temperature: -20～60℃
Storage temperature: -20～35℃
Battery Packing: Blue PVC
Lithium battery protection: short circuit protection, overcharge protection, over-discharge protection, over current protection, etc.
Application areas: wireless monitoring terminal, detection and control instruments, etc.

Effects of lithium-ion battery self-discharge:

1. Self-discharge leads to a decrease in capacity during storage Several typical problems caused by excessive self-discharge 

   A. The car has been parked for too long and cannot be started;
   B. The voltage of the battery before storage is normal, and the low voltage or even zero voltage is found when it is shipped;
   C. In summer, the car GPS is placed on the car, and after a period of time, it feels that the power or use time is obviously insufficient, and even the battery is bulging.

2. Metal impurity type self-discharge leads to blockage of the diaphragm aperture, and even pierces the diaphragm to cause a partial short circuit, endangering the safety of the battery; 
3. Self-discharge leads to an increase in the SOC difference between cells and a decrease in the capacity of the battery pack; 
4. Large differences in SOC can easily lead to overcharge and over-discharge of the battery;

lithium battery self-discharge test method:

• Voltage drop methodThe magnitude of self-discharge is characterized by the rate of voltage reduction during storage. This method is simple to operate, but the disadvantage is that the voltage drop cannot intuitively reflect the loss of capacity. The voltage drop method is the simplest and most practical, and is the method commonly used in current production.
• Capacity decay methodThat is, the percentage of capacity reduction per unit time is expressed.
• Self-discharge current method IsdAccording to the relationship between capacity loss and time, the self-discharge current Isd during battery storage is calculated.