A method for evaluating the state of health of power batteries for rail transit

Abstract

The invention relates to a track traffic power battery state of health (SOH) evaluation method. The method comprises the following steps: step one, based on a battery state of charge-open circuit voltage (SOC-OCV) model, extracting battery SOC-OCV model parameters a, b, c and d; step two, counting change trends of the SOC-OCV model parameters of more than five batteries along with aging, and obtaining development rules of battery SOC-OCV model key parameter values as the batteries age; step three, based on the development rules of the battery SOC-OCV model parameters as the batteries age, establishing function relations between SOHs and the model parameters in the first step by use of a linear regression method and obtaining a new SOH definition formula; and step four, evaluating the SOHs of the batteries based on the new SOH definition formula obtained in the third step. The rack traffic power battery SOH evaluation method provided by the invention can reflect the fundamental cause of battery aging and is quite high in precision.

Description

technical field [0001] The invention relates to the technical field of battery SOH (state of health, state of health) evaluation methods, in particular to a method for evaluating the state of health of power batteries used in rail transit. In particular, it refers to the evaluation of battery health status based on the battery SOC-OCV model parameter evolution law. SOC is the state of charge, state of charge; OCV is the open circuit voltage, open circuit voltage. Background technique [0002] In the past research, the SOC evaluation of the state of charge of the power battery has always been a research hotspot, but the SOH evaluation as a measure of the state of health of the power battery has not been extensively studied. The power battery state of health SOH reflects the ability of the battery to provide power and energy in the current state. When the SOH is at a low level, the battery is likely to fail suddenly during the working process, so the accurate evaluation of S...

AI Technical Summary

Problems solved by technology

[0004] The electrochemical model requires a detailed understanding of each electrochemical reaction of the battery during use, and accurately describes these electrochemical projections with electrochemical equations. Therefore, the accuracy of SOH evaluation depends on the use path of the battery. Not only that, the establishment of electrochemical equations requires Setting boundary conditions and initial conditions, so the complexity is high, it is difficult to apply this method in practice;

[0005] The combination of intelligent algorithms and historical data has achieved satisfactory evaluation accuracy in the laboratory, but the current changes in actual use are complex, so this accuracy cannot be guaranteed in practical applications. Not only that, the intelligent algorithm Models combined with historical data are often implemented offline, so there is still a distance from practical applications

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