Secondary Battery Deterioration Evaluation Using Dynamic Current Control

The patent changes the evaluation parameter from simple voltage drop to voltage drop per unit current ((V1-V2)/A1). This parameter transformation compensates for the effects of temperature and resistance variations, as the current-normalized voltage drop remains relatively stable across different operating conditions. The control map stores threshold values RO for this normalized parameter, enabling accurate deterioration determination regardless of temperature or resistance changes.

The patent introduces dynamic adaptation by determining the discharge current A1 based on real-time battery information (capacity, temperature, resistance) rather than using a fixed constant current. The control map provides different current values A1 corresponding to different battery states, allowing the evaluation to adapt to varying battery conditions while maintaining operational simplicity through automated current selection.

The patent introduces an intermediary control map that mediates between the simple voltage measurement and the complex battery state (temperature, resistance, capacity). The control map stores pre-calculated threshold values RO and corresponding current values A1 that account for temperature and resistance effects. This intermediary structure enables the system to achieve high accuracy without directly measuring temperature or resistance, as the control map encapsulates these factors.