Battery State Estimation Using Segmented SOH and SOC Modules

The battery state estimation system is segmented into two independent but interconnected modules: SOH estimation module and SOC estimation module. The SOH estimator uses degradation factors (temperature, charge/discharge cycles, current rate) to estimate battery health, while the SOC estimator uses the estimated SOH as input to improve SOC accuracy. This segmentation allows each module to specialize in specific degradation factors without requiring a complete redesign of the entire estimation system.

The system performs preliminary SOH estimation before SOC estimation. The SOH estimator first processes degradation data and outputs an estimated SOH value, which is then used as a prerequisite input for the SOC estimator. This preliminary action ensures that the SOC estimation accounts for battery degradation effects before calculating charge state, thereby improving overall accuracy without adding significant system complexity.

The estimated SOH acts as an intermediary that bridges the degradation factors and the final battery state estimation. Instead of directly incorporating complex interactions between temperature, cycle life, and current rate into the SOC model, the system uses the SOH estimator to process these degradation factors and produce an SOH value that serves as a mediator input for the SOC estimator. This intermediary approach simplifies the overall system architecture while maintaining reliability.

The system changes parameters dynamically based on degradation levels. The SOC estimator updates electrode parameters (such as electrode volume ratio, film resistance, and particle size) based on the estimated SOH and the state of degradation. This parameter adaptation allows the estimation model to account for degradation effects without requiring a completely complex degradation model, thereby improving reliability while controlling system complexity.