Single point diagnosis of short circuit abuse condition in lithium-ion battery through impedance data

Lithium-ion batteries have a confined frame of stability features in context to voltage and temperature. Abrupt attenuation in the above features may result in safety concerns. The present work provides an imperative experimental single point impedance diagnostic for analysis of external (soft) short-circuit abusiveness as per IEC 62660-2(3) of PANASONIC NCR 18650PF 3.6 V 2750 mAh lithium-ion battery using 5 m omega resistance applied externally across battery terminals using BK Precision 8510 programmable DC load. Characterization of the abusiveness of the test battery has been performed through the electrochemical AC impedance for single point impedance measurement at 1 KHz. Variations in the battery parameters during the test condition were also measured and analysed. Results reveal that the test battery experiences a rapid increase in the temperature rise where anodic reactions in the battery crop up at an initial temperature of 60 degrees C with a sudden clamp in temperature around 85(o)C to 100(o)C indicating breakdown occurring at sold-electrolyte interphase (SEI) layer. Cathode side reactions have initiated at 100 degrees C resulting in oxidation of the electrolyte and thermal runaway has been observed with a steep temperature rise of 45 degrees C/min. AC impedance data for abused battery showed a drastic increase in equivalent series resistance (ESR) up to 78.1 omega and diffusion constant (W) up to 200 omega/s compared to the fresh battery. These changes show the kinetic effects, due to the impact of high-frequency on the anode and low-frequency effects on mass transportation, inside the battery. Finally, the battery AC impedance data were validated through data available in published work and KK-transformation. The results shed light on a detailed study of the various electrochemical phenomenon in a lithium-ion battery that occurred during short-circuit (external) abuse condition.