Battery Capacity Allocation Standard Analysis

1. Lithium battery consistency definition

The consistency of lithium batteries refers to the convergence of important characteristic parameters of a group of lithium batteries, which is a relative concept, not completely consistent, only close to consistent. Multiple series cells in the same battery pack, each parameter difference is in the smallest range is good for consistency.

Adding the time dimension, consistency refers to the consistency of all characteristic parameters during the life cycle of all cells in the battery pack. It is necessary to consider the inconsistency of capacity attenuation, internal resistance growth, and aging rate. The life of the entire battery pack is our focus on consistency.

The battery pack is composed of multiple cells (such as a single cell of 3.7V 2000mAh), such as to assemble into a battery pack 14.8V6000mAh: 4 cells in parallel with 3 cells in series.

Lithium battery pack assembly requires cell consistency, several cells or dozens of cells in series and parallel discharge at the same time, if the consistency is not good, it will lead to uneven discharge, a discharge is finished, a half has not been discharged, resulting in the battery can’t reach the maximum power discharge.

Lithium battery pack configuration requirements:

capacity difference ≤30mAh, 

voltage difference ≤3mV, 

internal resistance difference ≤3m Ω, of course, the model of the cell must be the same.

2. Lithium battery capacity allocation group standard

1) Detection of charge and discharge rate of lithium batteries

Cell capacity < 2000mAh: charge and discharge rate at 1C.

Cell capacity ≥2000mAh: 0.5C charge and discharge rate.

Cell capacity ≥4000mAh: charge and discharge rate at 0.2C.

Only in the same grade can the pair cells be carried out.

2) Lithium cell assembly standard

3) Cautions

During the testing process, attention must be paid to safety. After the battery is found to be hot or short-circuited, it should be kept away from personnel and inflammable and explosive products.

In the process of testing, different suppliers, models, specifications, quality levels, good and bad products must be distinguished and labeled.

For cells with a stock time of 2 or 3 months, please execute << Cell Activation Standard >>.

The detection voltage is based on the 4-digit and half-digit voltmeter