Simultaneous diagnosis of cell aging and internal short circuit faults in lithium-ion batteries using average leakage interval

Accurate health diagnostics of lithium-ion batteries are indispensable for efficient utilization. A decrease in battery capacity not only diminishes the energy efficiency but also causes several detrimental effects, such as an internal short circuit (ISC) fault; these fault can lead to thermal runaway. However, the simultaneous impact of aging and ISC faults complicates the ability to distinguish between two factors within a singular discharging or charging process. This study focuses on the co-diagnosis of battery capacity and ISC faults, emphasizing that the amount of leakage current attributable to an ISC fault remains consistent at intervals where the average voltage is identical during discharging and charging procedures. To perform this analysis, different equivalent circuit models and parameter tables are employed for the discharging and charging processes separately. Subsequently, the ISC fault and capacity are estimated using the estimated state of charge (SOC) of intervals. The practicality of the proposed method is evaluated through experiments under various dynamic profiles, ISC fault severities, aging degrees, and temperature conditions. The results substantiate the proposed method’s efficacy in co-diagnosing the capacity and ISC faults. Therefore, this method represents an advancement in the ongoing efforts to ensure the safe and effective deployment of lithium-ion batteries. •Method can quantitatively diagnose both li-ion battery capacity and internal short circuit faults.•Different circuit models and parameter tables separately used for charging and discharging.•Battery capacity can be estimated regardless of internal short circuit fault.•Method can be applied at different temperatures, fault severities and aging.•Battery safety is improved by accurately estimating internal short circuit fault and capacity.