Lithium ion battery three-order RC equivalent circuit model parameter identification method

Abstract

The invention discloses a method for identifying parameters of a three-order RC equivalent circuit model of a lithium ion battery. The method comprises the following steps: establishing the three-order RC equivalent circuit model of the lithium ion battery; obtaining the relationship between the open-circuit voltage Uoc of the lithium ion battery and the SOC; testing the lithium ion battery by adopting a novel parameter identification working condition to obtain lithium ion battery test data; according to lithium ion battery test data, battery model parameters are identified by using a recursive least square method based on specific constraint conditions. According to the method, the specific constraint condition is obtained under the novel parameter identification working condition, and the three-order RC equivalent circuit model parameters are identified by using the recursive least square method based on the specific constraint condition, so that the identification difficulty can be reduced, and the model parameters are accurately identified; compared with a second-order equivalent circuit model constructed based on HPPC test data identification by using a recursive least square method, the battery model constructed by the method has higher model precision.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a method for identifying parameters of a third-order RC equivalent circuit model of a lithium ion battery applied to a lithium ion battery management system. Background technique [0002] The state of charge of the battery is one of the important basis for the battery management system to formulate the balance strategy, but the electrochemical reaction inside the lithium-ion battery is complex and changeable, and its SOC (State of charge, state of charge) cannot be directly measured and obtained, only based on The battery-related physical quantities are estimated by a certain method. The model-based method is a commonly used SOC estimation method. This method uses a battery model with an appropriate estimation method to obtain the battery SOC, and its estimation accuracy is directly related to the battery model accuracy. [0003] The widely used battery models are ...

AI Technical Summary

Problems solved by technology

Usually, the number of RC links represents the order of the model. The increase of the order will improve the accuracy of the model, but the difficulty of parameter identification of the model will also increase significantly.

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