Lithium ion battery pack is mainly used to test the electrical performance of the battery cells after screening, matching, packaging and assembly to determine whether the capacity and pressure difference are qualified.
The consistency between the series and parallel cells of the battery needs special consideration in the battery pack. Only with good capacity, state of charge, internal resistance and self discharge consistency can the capacity of the battery pack be fully developed and released. If the consistency is poor, the overall performance of the battery pack will be seriously affected, and even overcharge or overdischarge will be caused, resulting in potential safety hazards. And a good matching scheme is an effective way to improve the monomer consistency.

Charging mode

The proper charging system has an important effect on the discharge capacity of the battery. If the charging depth is shallow, the discharge capacity will be correspondingly reduced. If overcharged, the chemical active substances of the battery will be affected, causing irreversible damage, and reducing the capacity and life of the battery. Therefore, it is necessary to select appropriate charging rate, upper limit voltage and constant voltage cut-off current to ensure optimal charging efficiency and safety and stability while realizing charging capacity.
Lithium ion battery is restricted by the environmental temperature, and the battery capacity will be affected if the temperature is too high or too low. The cycle life of the battery may be affected if it works at high temperature for a long time. If the temperature is too low, the capacity is difficult to play.
The discharge rate reflects the high current charging and discharging capacity of the battery. The rate is too small and the charging and discharging speed is slow, which affects the test efficiency; If the rate is too large, the capacity will be reduced due to the polarization effect and thermal effect of the battery, so it is necessary to select a suitable charge and discharge rate.

discharge rate 

Discharge rate is a very important index for power type power battery. The high rate discharge of the battery is a test for the positive and negative materials and electrolyte. For the positive electrode material lithium iron phosphate, its structure is stable, the strain during charge and discharge is small, and it has the basic conditions for large current discharge. However, the unfavorable factor is the poor conductivity of lithium iron phosphate. The diffusion rate of lithium ions in the electrolyte is the main factor affecting the discharge rate of the battery, and the diffusion of ions in the battery is closely related to the structure of the battery and the electrolyte concentration. The available capacity of the battery decreases with the increase of the discharge current.

When the lithium-ion battery is discharged, the national standard 1C is generally selected, and the maximum discharge current is usually limited to 2-3c. When a large current is discharged, a large temperature rise and energy loss will occur. Therefore, it is necessary to monitor the temperature of the battery pack in real time to prevent damage to the battery caused by excessive temperature and reduce the service life of the battery.