Battery Pack SOC Monitoring for Internal Short Detection

The patent changes the detection parameter from voltage difference or current integral to state of charge (SOC) change. SOC is calculated by integrating current over time and normalizing by capacity, transforming the raw current data into a meaningful state parameter that directly reflects battery charge status. This parameter transformation enables accurate fault detection by comparing SOC changes across battery cells, resolving the contradiction between simple detection methods and accurate fault identification.

The patent performs preliminary SOC calculation and comparison during the charging or discharging process itself, rather than waiting for the battery to reach a resting state. By continuously monitoring and comparing SOC changes of individual battery cells against the average SOC change during active operation, the system can detect internal short circuit faults in real-time, eliminating the need for prolonged rest periods while maintaining detection reliability.

The patent segments the overall battery pack monitoring into individual cell-level SOC calculations. By calculating SOC for each battery cell separately using its own capacity and the common charge/discharge current, then comparing individual SOC changes against the average, the system extracts individual cell fault information from the series connection structure. This segmentation approach maintains the system's voltage and capacity benefits while enabling precise individual cell fault detection.