SOC (state of charge) estimation method

Abstract

The present invention discloses an SOC (state of charge) estimation method. According to the method, a battery OCV-SOC relationship module, a parameter acquisition module, an offline identification parameter value, a parameter discrete state space model, a battery parameter online identification module, a battery dynamic parameter update module and a battery SOC estimation module. The method includes the following specific steps that: 1, a discharge-standing experiment is performed, an OCV-SOC relationship expression is obtained through fitting, parameter values in an equivalent circuit model are identified; 2, a battery second-order RC system discrete state space model is established, and the battery model parameters are identified online and dynamically updated; and 3, the SOC of a battery is estimated online. With the method of the invention adopted, the defects of inaccuracy and accumulative error of the initial value of the SOC of a battery of in an ampere-hour integration method can be eliminated. The method is applicable to the dynamic change of the characteristics of the battery, can improve the accuracy of SOC online estimation and can be widely applied to the electric vehicles and storage battery management system field. The method has the advantages of high battery model precision, fast convergence, high stability and high reliability.

Description

technical field [0001] The invention relates to the field of electric vehicle battery management systems, in particular to an SOC estimation method. Background technique [0002] Smart grid, photovoltaic power generation, wind power generation, electric vehicles and other new energy industries, the basic common key technology is essentially the application technology of battery group integration and control system. The battery management system is responsible for coordinating battery status detection, power balance, thermal management, energy distribution and many other aspects, which is of great significance to prolonging battery life, improving battery safety, efficient operation, and reducing the cost of full life cycle use. The state of charge is an important indicator that reflects the battery's remaining power and power output capability, and is an important basis for battery charge and discharge control, health status detection, energy distribution, and power balance....

AI Technical Summary

Problems solved by technology

[0004] In summary, the existing battery SOC estimation methods have certain inconveniences and defects to varying degrees in practical applications, so it is necessary to make further improvements

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