Assessing Lithium-ion Battery Functionality Post-Thermal Management with Water Mist

The danger of lithium-ion batteries in electric vehicles (EVs) is intensified when they are used at inappropriate temperatures, leading to self-heating and eventually contributing to thermal runaway. Nevertheless, there is uncertainty through the safety of reusing batteries after they have been exposed to heat damage and water mist from fire extinguishers. To address these concerns, this study aimed to experimentally investigate the impact of temperature on batteries and introduce a thermal management using a water mist. Subjecting a battery to a temperature of 100°C for a duration of 39 minutes can immediately detect inoperability from a sudden drop in voltage. The use of water mist was proposed to rapidly mitigate the heat production inside the battery. The state of health (SOH) and the impedance were employed to confirm the battery’s functionality after exposure to thermal abuse and water spraying. The SOH of fresh cells was measured as a reference line for comparison to tested batteries. It was noted that new batteries had about 95% SOH after undergoing 50 cycle tests. Batteries subjected to thermal abuse and water mist following 10 test cycles exhibited a significantly accelerated deterioration rate, about 2.5 to 3.5 times higher than batteries undergoing regular cycle operations. Even through exposure to water mist may significantly impact the health of the battery, leading to noticeable deterioration, it remained functional. However, it is importance to investigate the long-term stability and reliability of such batteries over extended operation.