How to control the consistency of lithium-ion batteries?
Inconsistencies in cell performance arise during the manufacturing process and worsen during use. Within the same lithium-ion battery pack, weaker cells remain weaker and accelerate their decline. The dispersion of parameters between individual cells increases with aging. Currently, engineers address individual cell inconsistencies primarily from three aspects: individual lithium-ion battery sorting, thermal management after pack assembly, and the battery management system's supply balancing function when minor inconsistencies occur.
1. Improve cell consistency: Minimize the number of material suppliers; larger batch sizes for materials and batteries are more conducive to improving consistency and reducing batch-to-batch variations; maximize the automation level of equipment; selecting high-precision, high-stability equipment is beneficial for improving battery consistency.
2. Strict consistency screening must be performed when matching batteries: the larger the batch size of products produced in the same batch, the more guaranteed the consistency. Strict control must be exercised over mixing batches; ensure accurate detection of lithium-ion battery matching data, accurate battery screening, and proper data storage and analysis.
3. Add a safety protection equalization detection circuit or install a device that can perform equalization maintenance: ensure that the equalization function of the battery protection system is truly effective and prevent overcharging and over-discharging; protection system failure is a very important factor among the causes of lithium-ion battery failure.
To control the consistency of lithium-ion batteries, it is recommended to use automated battery manufacturing equipment. Each process should have self-inspection capabilities and sound quality control capabilities. If the consistency of lithium-ion battery packs is to be controlled, the consistency of voltage, capacity, power supply internal resistance, self-discharge, etc. should be matched. This is usually achieved through screening functions.
