Inconsistency of lithium ion batteries will affect the service life of the battery pack and reduce the performance of the battery pack. Inconsistency of lithium-ion battery groups refers to differences in capacity, voltage, internal resistance, self discharge rate and other parameters of single battery, which is caused by different combination structure, operating conditions, operating environment and battery management of lithium-ion battery groups. Inconsistency of single battery is an important factor affecting the performance of the battery pack, which can reduce the available capacity of the battery pack and reduce the cycle life of the battery pack.

The consistency of lithium-ion battery pack refers to the differences in capacity, internal resistance, SOC, etc. between single batteries in series in the battery pack, which directly determines the service performance of the whole battery pack, thus affecting the power performance and range of electric vehicles. The main reasons for the inconsistency of lithium-ion batteries in groups are the initial differences of single batteries and the differences in the structure, service conditions and environment after the batteries are grouped.

In order to alleviate the problems of performance degradation and life reduction caused by battery grouping, the manufacturing process of the battery can be optimized to reduce the initial difference of the battery; Screening shall be carried out before the batteries are grouped to group the batteries with less inconsistency; When assembling the battery pack system, the influence of connection mode and structure on inconsistency shall be fully considered; Reasonable battery management, effective balance and thermal management shall be carried out in the use process to reduce the inconsistency caused by different use conditions.