A method and system for equalization-induced maintenance of segmented converter terminals for power batteries

Abstract

This invention discloses a method and system for segmented converter-end equalization induced maintenance of power batteries. It triggers a mid-stage induced maintenance mode by monitoring the quiescent time and average state of charge (SOC). A bidirectional converter device applies a converter disturbance containing at least two disturbance frequencies to the battery pack, simultaneously acquiring the dynamic response information of each individual cell and constructing impedance characteristics. The impedance characteristics of each individual cell are compared with a preset reference impedance model. Based on the deviation, the cell to be maintained is determined. A restorative microcurrent waveform is generated with the goal of reducing the deviation and applied to the battery pack, causing the cell to be maintained to produce an impedance convergence response. Maintenance stops when the deviation meets a preset exit condition. This invention does not rely on the full-charge high-voltage range or the static voltage difference criterion, and can achieve online induced maintenance in the mid-stage SOC range. It is suitable for battery systems operating at a long-term partial state of charge, such as energy storage and backup power systems.

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