Battery Pack DCIR Estimation Using Parallel Compensation Current

The patent segments the battery system into individual battery pack units, each with its own management system. This allows separate monitoring and estimation of each pack's internal resistance, enabling accurate measurement of old packs even when operated in parallel with new packs. The segmentation isolates measurement processes to eliminate interference from performance variations between different aged packs.

The patent introduces an intermediary calculation method using compensation current as a mediator. By measuring the compensation current that flows between battery packs with different states of charge, the system indirectly estimates internal resistance without direct measurement interference. This intermediary approach allows accurate resistance estimation of old packs while maintaining parallel operation with new packs.

The patent implements a feedback mechanism where the battery management system continuously monitors compensation current between battery packs and uses this information to iteratively estimate internal resistance. The system feeds back the estimated resistance values to adjust operational strategies, creating a closed-loop measurement process that maintains both simplicity and accuracy for old battery packs.

The patent replaces traditional direct electrical measurement methods with an indirect calculation approach based on compensation current analysis. Instead of using complex measurement instruments to directly measure internal resistance, the system substitutes mechanical/electrical measurement with computational estimation using readily available current data, maintaining operational simplicity while improving measurement precision.

The patent enables the battery system to perform self-diagnosis and self-monitoring through automated resistance estimation. The system uses its own operational data (compensation currents between packs) to continuously assess the health of old battery packs without external intervention or removal. This self-service capability maintains both measurement accuracy and system productivity simultaneously.

The patent performs preliminary resistance estimation continuously during normal operation, so that by the time inspection or replacement is needed, the system already has accumulated data about old battery pack degradation. This preliminary monitoring allows proactive operational strategy adjustment without requiring system downtime for measurement, maintaining both accuracy and productivity.