Lithium battery SOC estimation method of off-line data segmentation correction

Abstract

The invention discloses a lithium battery SOC estimation method of off-line data segmentation correction. The method is mainly applied to a battery management system of an electric vehicle and is used for correcting an actual capacity of a lithium battery and eliminating an accumulation error of a traditional ampere-hour integral method. The method comprises the following steps of establishing a battery equivalence circuit model; acquiring an OCV-SOC curve; using a terminal voltage response curve at the time that battery discharging is ended to carry out off-line parameter identification on the equivalence circuit model; calculating a battery health state SOH; using an ampere-hour integral method to calculate a current value of the SOC in real time; using the battery health state to correct a SOC value; using off-line data to carry out segmentation elimination on the accumulation error in the ampere-hour integral method. By using the method of the invention, the battery SOC can be accurately estimated and the accumulation error of battery SOC estimation performed through using the ampere-hour integral method is eliminated.

Description

technical field [0001] The invention relates to the field of battery management systems for electric vehicles, in particular to a method for estimating the SOC of a lithium battery with offline data segmentation correction. Background technique [0002] In the operation of electric vehicles, the state of charge (SOC) of the power battery is an important parameter of the battery state, which is used to directly reflect the remaining power of the battery. In the hybrid power system, the battery SOC is also the optimal energy management strategy for the vehicle control system. important basis. Accurately estimating the SOC value of the power battery has important research significance for prolonging battery life, improving battery safety and reliability, and improving the performance of electric vehicles. [0003] Battery SOC is affected by many factors and cannot be directly measured by sensors. It must be estimated by measuring physical quantities such as battery voltage, op...

AI Technical Summary

Problems solved by technology

[0004] The open circuit voltage method, used alone is only suitable for the parking state of electric vehicles, and cannot be estimated online and dynamically

[0005] In the ampere-hour integration method, the estimation accuracy largely depends on the current measurement accuracy, and the cumulative error cannot be eliminated

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