A correction method and device for power battery SOC estimation based on ocv-soc curve characteristics

Abstract

The invention discloses an OCV-SOC curve characteristic-based power battery SOC (state of charge) estimation correction method and device. The correction method mainly comprises two parts, namely, boot-up correction and dynamic correction. According to the boot-up correction, coefficient SOC estimates are corrected based on the ranges of the plateau region, non-plateau region and transition region of an OCV-SOC curve where boot-up average voltage is located, and practical experiences. According to the dynamic correction, under a condition that charging and discharging current is low, and lasting time is long, correction is performed when the average voltage of batteries is high or low, or when the difference of a currently estimated and reported SOC value and an SOC value obtained through OCV table lookup is large. The SOC estimation device mainly comprises an acquisition module of a slave board, a judgment module of a high-voltage board, and a stratagem and execution module of a master board. With the correction method and device of the invention adopted, the correction opportunities of the SOC are increased, and the estimation accuracy of the SOC is improved. The correction method and device are of practical significance for the SOC estimation of power batteries.

Description

technical field [0001] The invention relates to the research field of power batteries, in particular to a correction method and device for power battery SOC estimation based on OCV-SOC curve characteristics. Background technique [0002] In the lithium-powered battery management system for electric vehicles, the estimation of the battery state of charge (SOC) is the core content of the battery management system. Whether the SOC estimation is accurate or not will directly affect the decision-making of the battery management system. Accurate SOC estimation can improve battery performance, improve battery reliability, prolong battery life, and provide a basis for electric vehicle vehicle control, and accurate SOC estimation It can also provide accurate mileage information for the driver, so how to accurately estimate the SOC is one of the key technologies of the battery management system. [0003] The estimation of SOC is related to parameters such as battery open circuit volt...

AI Technical Summary

Problems solved by technology

At present, a lot of research has been done on the accurate estimation of the SOC of the battery at home and abroad. However, due to the limitation of the hardware conditions of the battery management system in the actual management system, the commonly used method is still the combination of the simple and effective open-circuit integration method and the ampere-hour integration method.

The open circuit voltage method requires the battery to stand for a long enough time, and the SOC value changes significantly with the open circuit voltage, and cannot be estimated online, while the initial value of the ampere-hour integral method cannot be determined and there is a cumulative error of the sensor

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