Battery state of health (SOH) evaluation method and evaluation system

Abstract

The invention discloses a battery SOH evaluation method, which comprises the steps of performing charging and discharging test on a battery, and recording test data; performing data processing on thetest data to obtain a V-dQ / dV data point set, and performing filtering and noise reduction; identifying a peak value of the data point set, carrying out segmenting according to the peak value point, and performing polynomial regression on each segment of the V-dQ / dV to obtain an IC curve for qualitatively analyzing a battery attenuation mode; and integrating and then converting the IC curve to obtain a Q-V curve numerical model, performing data verification, and quantitatively analyzing the battery attenuation behavior by calculating optimal voltage curve reconstruction model parameters. According to the method, filtering and nonlinear regression operations are carried out on test data and a calculation result; influence of measurement noise on an analysis result is reduced, the method ishigh in adaptability and is used for various types of lithium ion battery systems, the battery attenuation mode is analyzed in a set and quantitative mode, a reasonable independent variable step length can be set for quantitative analysis, and the calculated amount is greatly reduced. The invention further provides a battery SOH evaluation system.

Description

technical field [0001] The invention belongs to the technical field of battery state of health evaluation, in particular to a battery state of health evaluation method and an evaluation system. Background technique [0002] The energy shortage and the aggravation of the environmental crisis have made the search for renewable energy sources to replace fossil fuels become the focus of the world. Chemical batteries for energy storage have been widely used in consumer electronics, new energy vehicles, large-scale energy storage power stations and other fields. [0003] Electrochemical power sources such as lithium-ion batteries will gradually age with the battery during use, manifesting as capacity decay, power loss, etc., until the functional requirements specified by the battery when it leaves the factory are lost. In order to ensure the stable and reliable operation of the battery system, it is necessary to accurately evaluate the state of health and the degree of attenuatio...

AI Technical Summary

Problems solved by technology

However, since the voltage curve characteristics of different types of batteries are very different, and the capacity of the battery will decay as the number of cycles increases, and the voltage curve will also be deformed, making the method of empirical formula fitting poor in adaptability and reliability

[0008] The Chinese invention patent application and document (J Cleaner Production, 2018, 193-379) with the publication number CN103576097B introduces a method based on the balance potential curve of positive and negative electrodes, using genetic algorithm, particle swarm algorithm and other algorithms to reconstruct the full battery voltage curve , to obtain a set of optimal key parameters, and then evaluate the battery attenuation mechanism, and obtain the attenuation value of the internal components of the battery. However, in the calculation process of this method, the test data is not preprocessed, but the error corresponding to each test data point is required , the amount of calculation is large, and if the points are taken at intervals in the test data, the influence of noise cannot be avoided

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