Balance control method for power battery pack of electric vehicle

Abstract

The invention relates to a balance control method for a power battery pack of an electric vehicle. The method comprises the steps of building a second-order thevenin model and an one-state hysteresis characteristics model of the single battery; performing charging / discharging test for single power battery; recording the ampere per hour of charging / discharging; calculating SOC theoretical value; performing current excitation on real time according to sampling time intervals; treating the actual end voltage of the single battery and the SOC theoretical value as the system input; performing the adaptive unscented kalman filter based SOC estimation method for the second-order thevenin model; performing the unscented kalman filter based SOC estimation method for the one-state hysteresis characteristics model; performing weighted summation and conversion for the two estimation results according to a model probability matrix to obtain interactive multi-model kalman filter; solving the optimal SOC estimation value; performing balance control for the battery pack through a Buck-boost circuit based on adjacent battery energy transfer and of a balance topological structure according to the SOC optimal estimation value. The method is simple and reliable, and high in practicability and performability.

Description

technical field [0001] The invention belongs to the field of electric energy management of power batteries of electric vehicles, in particular to a method for balancing control of power battery packs of electric vehicles. Background technique [0002] Due to the increasingly serious problems of energy shortage and environmental pollution, electric vehicles have attracted much attention due to their advantages such as low emissions and low fuel consumption. Vehicle-mounted power batteries will gradually replace non-renewable resources such as oil and natural gas as the main driving source for vehicles. In order to meet the voltage requirements of the electric vehicle drive system, dozens or even hundreds of power battery cells need to be connected in series to form a battery pack module. Due to the inevitable differences in the production process, the chemical composition ratio of the single batteries in the group is inconsistent, and there is a certain degree of difference i...

AI Technical Summary

Problems solved by technology

However, the capacity-based equalization method needs to accurately estimate the SOC of the single battery. If the accuracy of the SOC cannot be guaranteed, the reliability of the equalization will be greatly reduced.

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