Lithium ion power battery state-of-health estimation method based on machine learning

Abstract

The invention discloses a lithium ion power battery state-of-health estimation method based on machine learning. The method is used for estimating the state-of-charge (SOC) and the state-of-health ofa power battery in real time. Parameter identification is performed on an equivalent circuit model by establishing the equivalent circuit model of the lithium ion battery, and then a Uoc-SOC model isestablished, and the SOC is estimated. Training is carried out by using a large amount of offline data to obtain a neural network model which takes Uoc-SOC model parameters as input and takes the maximum available capacity as output. The method further has the following steps: performing curve fitting on Uoc and the SOC at the same moment to obtain to-be-identified parameters in the model, inputting the to-be-identified parameters into the neural network model obtained by training to obtain the maximum available capacity, returning the obtained Uoc-SOC model parameters and the maximum available capacity to the SOC estimation step, and updating the parameters of a state equation and an observation equation. According to the lithium ion battery state-of-health estimation method provided by the invention, online estimation is carried out for the battery health state, parameter updating is carried out on SOC estimation, and the estimation precision is improved.

Description

Technical field [0001] The invention relates to the technical field of state estimation of electric vehicle power battery management systems, and specifically to the joint estimation of the state of charge and health state of the power battery. Background technique [0002] With the depletion of global oil resources and the increasingly serious environmental pollution, electric vehicles have attracted people's attention as an energy-saving, environmentally friendly and sustainable means of transportation. As the power source of electric vehicles, the performance of power battery packs has always been the focus of research. When the battery of an electric vehicle is used, it needs to work within a reasonable range of voltage, current, and temperature. Therefore, the use of electric batteries in electric vehicles needs to be effectively managed. The specific equipment for battery management in electric vehicles is the Battery Management System (BMS). It not only ensures the...

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