Hybrid modeling method of retired power lithium battery

Abstract

The invention discloses a hybrid modeling method of a retired power lithium battery, and belongs to the field of power lithium battery application. The method comprises the following steps: establishing a first-order equivalent circuit model of a retired power lithium battery, and obtaining model parameters; performing secondary fitting on an error formed by the first-order equivalent circuit model by adopting a partial least square method, and establishing a deviation compensation model of the retired power lithium battery; and combining the first-order equivalent circuit model and the deviation compensation model to establish a hybrid model of the retired power lithium battery. According to the retired battery with the external characteristics changed to a certain degree, the basic external characteristics of the battery are described through the first-order equivalent circuit model, and the deviation compensation model based on partial least squares is established, so that the retired power battery modeling precision can be effectively improved; accurate estimation of battery state parameters and efficient energy management of a battery pack can be conveniently realized by a subsequent battery management system, and echelon utilization of retired power batteries is facilitated.

Description

technical field [0001] The invention relates to the application field of power lithium batteries, in particular to a hybrid modeling method for decommissioned power lithium batteries. Background technique [0002] Lithium batteries have become the most important energy storage components of current new energy vehicles. However, with the daily use of new energy vehicles, power lithium batteries will inevitably gradually age. Lithium batteries decommissioned from vehicles still have the potential value of continuing to be used in occasions with lower performance requirements, that is, decommissioned batteries still have cascade utilization value. The battery model is an important basis for system energy management in cascade utilization, and the acquisition of battery core state parameters (such as State of Charge (SOC), State of Health (SOH), etc.) also requires accurate battery models . [0003] Compared with brand-new batteries, retired lithium batteries have been used b...

AI Technical Summary

Problems solved by technology

However, historical data is missing during the initial use of lithium batteries, which makes it impossible to directly use a large amount of data to establish a data-driven battery model

The traditional empirical model only describes the external characteristics of the battery through mathematical functions, which obviously cannot meet the complex needs of decommissioned battery modeling

The electrochemical model has a large amount of calculation, many parameters and difficult to obtain

Commonly used equivalent circuit models generally need to increase the number of parallel resistor-capacitor networks in order to improve modeling accuracy. When applied to decommissioned power lithium batteries, it is likely to cause problems such as complex model structure and difficulty in online parameter identification.

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