Battery Equalizer Using State of Health to Prevent Premature Discharge Cutoff

The patent applies local quality by differentiating the equalization strategy based on the deterioration state of each battery. Instead of uniformly treating all batteries, the controller selectively performs equalization only on batteries with smaller deterioration, while excluding batteries with larger deterioration from equalization discharge. This localized approach prevents premature termination of overall battery discharge and maximizes dischargeable effective capacity.

The patent changes the control parameter from simple terminal voltage threshold to a composite criterion that includes both terminal voltage difference and deterioration state. By introducing deterioration state as an additional parameter, the system dynamically adjusts which batteries undergo equalization, thereby resolving the contradiction between voltage uniformity and dischargeable capacity.

The patent implements local quality by applying different equalization strategies to different subsets of batteries based on their deterioration states. Batteries with smaller deterioration undergo equalization discharge to maintain voltage consistency, while batteries with larger deterioration are excluded from equalization to allow them to discharge to their full capacity limits. This selective approach maintains voltage consistency where applicable while preserving overall dischargeable capacity.

The patent applies partial action by performing equalization only on a subset of batteries (those with smaller deterioration) rather than all batteries. This partial equalization is sufficient to control voltage variation among the equalized batteries while avoiding the harmful effect of prematurely stopping the discharge of the entire battery assembly.