A joint estimation method of SOC and SOT for square lithium battery with multiple time scales

Abstract

The invention relates to a multi-time scale square lithium battery SOC and SOT joint estimation method, which belongs to the technical field of battery management. The method is based on a control-oriented electrical-thermal coupling model of a prismatic lithium battery combined with an advanced multi-time scale estimation algorithm. The heat production-related parameters in the electrical model are determined in advance through experiments, and other parameters of the electrical model are obtained through online parameter identification, and then combined with the observer to realize the SOC estimation at the current moment. According to the SOC and temperature values ​​at the previous moment, the heat production rate of each discrete volume unit of the battery is determined, and the temperature distribution at the current moment is obtained. Then use the current temperature and SOC value to update the electrical model parameters, determine the heat production rate of the discrete volume unit, and iteratively update the SOC and SOT values. This method can well balance the estimation accuracy and computing resource utilization, and realize the robust, high fault tolerance, accurate and efficient monitoring of the electrothermal characteristics of lithium batteries under different time scales.

Description

technical field [0001] The invention belongs to the technical field of battery management, and relates to a joint estimation method of SOC and SOT of a square lithium battery with multiple time scales. Background technique [0002] At present, there have been many studies on the estimation of SOC or SOT of lithium batteries alone. Common SOC estimation methods are mainly ampere-hour integration method, open circuit voltage method, data-driven method, model-based method and some hybrid methods. Due to the ease of implementation, the ampere-hour integration method, the model-based method, and some simple hybrid methods, such as the combination of the ampere-hour integration method and the open-circuit voltage method, are widely used now. Common SOT estimation methods mainly include methods based on EIS measurements, methods based on simplified thermal models, methods based on data-driven methods, and methods combining EIS measurements and simplified thermal models. The curre...

AI Technical Summary

Problems solved by technology

However, for square lithium batteries, the assumption of uniform heat generation or concentrated heat source will introduce a large model error, which is not conducive to the capture and monitoring of the thermal characteristics of lithium batteries

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