Parametric investigation of partial incremental capacity analysis for Lithium-ion cells

The widespread deployment of Lithium-Ion Batteries in transport applications requires methods for accurate fault and degradation diagnostics. A popular electrochemical technique used for battery diagnostics is the Incremental Capacity Analysis. While effective, it ideally requires a low operating current, which is not feasible for real-life implementation. Therefore, a method called Partial Incremental Capacity was recently proposed. The method implements low current charging in a fixed voltage window during high current fast charging for Incremental Capacity Analysis, hence reducing the overall charging time. However, the implementation of Partial Incremental Capacity profile was limited to a unique set of parameters, thus providing limited evidence of its robustness. Hence, this communication experimentally investigates the effects of the low-current voltage window width and initial charging state on the features obtained using Partial Incremental Capacity. Results indicate that the voltage window width has a significant influence on the Partial Incremental Capacity results and therefore, requires careful consideration based on the diagnostic objectives. In addition, the results vary strongly between a partial and a full charge, revealing a novel path-dependence that was speculated to depend on phase equilibria and thermal conditions of the cell. Both results are relevant for general real-life implementation of battery diagnostics and hence require further exploration to develop detailed understanding and prevent misdiagnosis of battery degradation and faults. • Effect of voltage window and starting SOC on diagnostic capabilities of Partial Incremental Capacity (PIC) investigated. • Wider voltage window found to provide greater number of IC features useful for fault and degradation diagnosis. • Path-dependence observed in PIC results: partial charging resulted in disparate set of IC features compared to full charge. • Hysteresis and thermal condition of the cell speculated to cause the observed path-dependence.