A review on Lithium-ion battery failure risks and mitigation indices for electric vehicle applications

Electric vehicles (EVs) are leading the way towards a more sustainable and eco-friendly future, helping the transportation sector moving closer to the carbon neutrality. Batteries hold a pivotal role in EVs due to their substantial influence on the vehicles' cost, performance, and safety. Lithium-ion batteries (LIBs), commonly used in EVs, are valued for their relatively longer lifespan, high energy storage density and no memory-effects; however, these batteries can pose safety risks in case of their failure. This study comprehensively overviews various LIBs used in EVs. It focuses primarily on the internal faults within LIBs covering their types, abusive scenarios, key feature indicators, safety enhancements, and fire characteristics. Any of the mechanical or electrical or thermal abusive scenarios is observed to eventually cause internal short circuit and hence, thermal runaway in LIBs. Overcharging is found to alter the porosity of cathode, anode and separators of LIBs whereas, over dis-charging is reported to degrade its capacity. LIBs, when exposed to abnormal working scenarios would face increase in temperature, swelling and gas release; Analysing these vent gases is reported as an effective way to corroborate the failure mechanism of LIBs. This work sheds light on LIB failure mechanisms behind the specific fault cases, highlights the battery characteristics that signal faults, and their instrumentation techniques. Furthermore, this review reports several challenges in the existing literature, provides insights and guidance for researchers to create safer and more durable EV batteries.