Method and system for estimating open-circuit voltage on line based on gas-liquid dynamic battery model

Abstract

The invention provides a method and a system for estimating an open-circuit voltage on line based on a gas-liquid dynamics battery model. The method comprises the following steps: estimating a first open-circuit voltage of a battery through a gas-liquid dynamics open-circuit voltage battery model; looking up an open-circuit voltage-capacity table according to the first open-circuit voltage to obtain a first capacity; taking the first capacity as an initial value, and obtaining a second capacity by using a micro-step ampere-hour integral method; looking up a capacity-open-circuit voltage tableaccording to the second capacity to obtain a second open-circuit voltage; estimating a end voltage of the battery through a gas-liquid dynamics end voltage battery model; calculating a coefficient matrix and a covariance matrix of an extended Kalman filtering algorithm of the gas-liquid dynamics open-circuit voltage battery model; and updating the coefficient matrix and the covariance matrix of the extended Kalman filtering algorithm of the gas-liquid dynamics open-circuit voltage battery model, and then circulating to finish online identification of model parameters and online estimation of the open-circuit voltage of the battery. According to the method, model parameters and initial values do not need to be identified or recognized before the open-circuit voltage of the battery is estimated.

Description

technical field [0001] The invention relates to the field of online estimation of the open circuit voltage of a power battery, in particular to a method and system for online estimation of the open circuit voltage based on a gas-hydrodynamic battery model. Background technique [0002] With the rapid development of the national economy and continuous social progress, the material living standards of the public have been continuously improved. At the same time, as the main means of transportation for people to travel - the automobile is developing rapidly, and the global oil storage is decreasing. Therefore, countries all over the world are making great efforts Encourage the development of new energy vehicles, especially electric vehicles. As the core power component of hybrid and electric vehicles, the power battery directly determines the vehicle performance of new energy vehicles, not only restricts its development from scientific research to industrialization, but also de...

AI Technical Summary

Problems solved by technology

The equivalent circuit model takes the simplest first-order RC circuit model as an example. Although it is simple and intuitive, its estimation accuracy is low. Although the estimation accuracy of the high-order RC circuit model has been improved to a certain extent, the corresponding calculation The complexity and calculation time are also significantly increased, and it is difficult to realize the online estimation of the open circuit voltage on the vehicle

The electrochemical model mainly reflects the internal chemical mechanism of the power battery from a microscopic point of view. At the same time, it uses quite complex partial differential equations to describe the relationship between microscopic information (ion concentration, distribution) and battery macroscopic information (voltage, current, resistance). Although fairly accurate, it requires complex calculations, making it difficult to achieve online estimation of circuit voltages on electric vehicles

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