Method for estimating SOC (State of Charge) of lithium battery under consideration of drift current value in sensor

Abstract

The invention relates to a method for estimating the SOC (State of Charge) of a lithium battery under the consideration of drift current value in a sensor. The method comprises the following steps: fitting the relationship between different temperatures and actual discharge capacity, and fitting the relationship between different discharge rates and the actual discharge capacity; estimating a current SOC with a Drift-Ah integral method as a state module, establishing a battery voltage-SOC-current function relationship, and discretizing the function relationship to obtain a system state equation; and carrying out a discharge experiment on the battery in an environment of 20+ / 2 DEG C, and estimating the SOC with an SCKF algorithm. The SOC can be estimated more accurately under the consideration of the influences of the two parameters of different temperatures and different discharge rates on battery capacity. Low, medium and high models are set under the consideration of the changes of SOC model parameters, so that the estimation accuracy is improved. The influence of drift current on the estimation accuracy can be reduced effectively, and the SOC of a power battery can be estimatedmore accurately.

Description

technical field [0001] The invention relates to the technical field of state-of-charge estimation of lithium batteries, in particular to a method for estimating the SOC of a lithium battery considering the drift current value in a sensor. Background technique [0002] As the core component and main power source of new energy vehicles, the power battery is very important to carry out reasonable and perfect monitoring and management. At present, the classic SOC estimation strategies include the ampere-hour integral method, the neural network method, the discharge experiment method, the open circuit voltage method, and the Kalman filter. However, the experimental data of current battery models and estimation methods are all detected by idealized sensors. Due to the limited accuracy of the sensor in actual use, there is a drift current value during actual measurement, that is, non-zero mean noise. If the drift current value is not considered, the estimated value of SOC will be ...

AI Technical Summary

Problems solved by technology

In the actual use process, due to the limited accuracy of the sensor, there is a drift current value in actual measurement, that is, non-zero mean noise. If the drift current value is not considered, the estimated value of SOC will be far from the actual value.

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