Sorting method for batteries

Abstract

The invention brings forward a sorting method for batteries. The method comprises the following steps: respectively acquiring electrochemical impedance spectrums of n to-be-sorted batteries under a plurality of preset sorting conditions, wherein the preset sorting conditions comprise preset temperature and a preset charged state, and n is a positive integer; acquiring an equivalent circuit model and carrying out fitting on the electrochemical impedance spectrums by using the equivalent circuit model so as to obtain circuit parameter values corresponding to the electrochemical impedance spectrums; screening the plurality of preset sorting conditions according to the electrochemical impedance spectrums and the circuit parameter values so as to obtain a first sorting condition; constructing impedance vectors corresponding to each battery according to the circuit parameter values corresponding to the first sorting condition; and carrying out cluster analysis on the n batteries according to the impedance vectors so as to realize sorting of the n batteries. According to the method provided by embodiments in the invention, the first sorting condition applicable to sorting of lithium ion secondary batteries is screened, then the batteries are sorted according to physical quantity of battery internal information under the first sorting condition, so accuracy of battery sorting is substantially improved.

Description

technical field [0001] The invention relates to the technical field of batteries, in particular to a battery sorting method. Background technique [0002] Due to the limited energy density and volume density of lithium-ion secondary batteries at this stage, in practical applications, such as using lithium-ion secondary batteries as energy storage media to drive battery cars and other devices that require high power and high energy, often need Many lithium ion secondary batteries of the same type are used in groups. However, due to the inconsistency between the cells, the performance of the battery pack is often lower than that of the cells in terms of lifespan and so on. Among them, the inconsistency of single cells in the battery pack often comes from two aspects: on the one hand, the initial internal inconsistency caused by factors such as materials and the manufacturing environment in the manufacturing process; Epigenetic extrinsic inconsistencies caused by factors such...

AI Technical Summary

Problems solved by technology

However, in related technologies, EIS is measured at room temperature and at full state of charge (FSOC). At this time, the battery impedance is very small. For example, the impedance of a large battery is at the milliohm level. The difference between them is difficult to observe, and even the noise in the measurement process will seriously affect the sorting results, so the sorting results are not accurate

Images