Method and device for evaluating uniformity of cascaded battery packs

Abstract

The embodiment of the invention discloses a method and device for evaluating the uniformity of cascaded battery packs. According to the method and the device, the disadvantages that the difference of intrinsic parameters (such as open-circuit voltage, available capacity and internal resistance) of single batteries in the battery packs is difficult to be truly described, evaluation indexes are not comprehensive enough, and the applicability is relatively poor in an existing uniformity online evaluation technique are solved. A distance similarity index calculation method based on a dynamic time warping strategy is developed based on a measured voltage curve of the single batteries, influence factors which cause the voltage difference of the single batteries due to different SOCs can be eliminated in a self-adaption manner, the evaluation of operational characteristic difference of the single batteries in charging-discharging processes is realized, and compared with an existing uniformity extraction method based on voltage difference of each discrete moment, intrinsic information of the batteries is assisted to be excavated; and on this basis, an abnormal battery statistics recognition method based on a stepwise iteration strategy is developed, the uniformity evolution of the cascaded battery packs is realized, and the effective technical support is provided for operation maintenance.

Description

technical field [0001] The invention relates to the field of series-structured battery packs, in particular to a consistency evaluation method and device for series-structured battery packs. Background technique [0002] Lithium-ion batteries have been widely used in new energy vehicles and large-scale energy storage due to their advantages such as high energy density, long cycle life, low self-discharge rate, no memory effect and no pollution. Factors such as the operating environment, operating time, and operating conditions of lithium-ion batteries will significantly affect the performance of the battery. With the cycle of charge and discharge, the inconsistency between single cells will increase, and the performance of the battery pack will decline accordingly, thereby reducing the overall service life. life. Therefore, the development of real-time online consistency evaluation technology is the key to ensuring good consistency of the battery pack during use, and it pla...

AI Technical Summary

Problems solved by technology

[0004] The embodiment of the present invention provides a consistency evaluation method and device for a battery pack with a series structure, which solves the problem of the existing online consistency evaluation technology, which often only simply evaluates the voltage difference between each single battery at each discrete time, and extracts the average value , variance, slope and other statistical indicators, although it can characterize the consistency of each single battery to a certain extent, it is greatly affected by the inconsistency of SOC, which makes it difficult to truly describe the intrinsic parameters of the single battery in the battery pack (such as open circuit Voltage, usable capacity, internal resistance, etc.), the calculated consistency evaluation index is not comprehensive enough, the error is large, and the technical problems of poor applicability

Images