Lithium battery SOC estimation method and system

Abstract

The invention discloses a lithium battery SOC (State of Charge) estimation method and system. The lithium battery SOC estimation method comprises determining the function relationship between each circuit parameter and the SOC in a lithium battery equivalent circuit; establishing an off-line model based on the function relationship; based on the off-line model, establishing a non-linear state space model for SOC on-line estimation; and utilizing a non-linear rolling horizon estimation method to perform on-line estimation for the SOC in the non-linear state space model so as to acquire the SOC estimated value. The lithium battery SOC estimation method and system utilize the non-linear rolling horizon estimation method to estimate the SOC of the lithium battery, can quickly reduce the influence of the SOC initial error on SOC estimation and reduce the influence of the accumulated error for current measurement on SOC estimation, performs explicit constraint on the SOC estimation range so as to guarantee the accuracy and feasibility for lithium battery SOC on-line estimation, and can greatly improve the effectiveness and reliability of a battery management system.

Description

technical field [0001] The present invention relates to a battery management system, in particular to a lithium battery SOC (State of Charge, state of charge) estimation method and system. Background technique [0002] With the rise of information technology and new energy, lithium-ion batteries are increasingly used in portable electronic devices, electric vehicles, home energy storage and space due to their advantages such as high energy density, high output power, and long charge and discharge life. technology and other emerging technology fields. Estimation of battery state of charge is one of the key functions of Li-ion battery management systems, which is crucial for improving battery utilization and extending battery life. At present, the current integration method is mainly used in the SOC estimation of the battery management system. Since the current integration method is a pure integration link, the initial error of the SOC cannot be eliminated, and the cumulative...

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Problems solved by technology

[0003] The technical problem to be solved by the present invention is to overcome the inability to eliminate the initial error of the SOC when the current integration method is used to estimate the SOC of the lithium battery in the prior art, and the cumulative error generated in the current measurement will continue to increase with the increase of the running time. Adding defects such as increasing, providing a lithium battery SOC estimation method and system, the method uses a nonlinear rolling time domain estimation method to conduct online real-time estimation of lithium battery SOC

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