Early Detection of Thermal Runaway of Lithium-Ion Battery-An Experimental Study

Lithium-ion batteries (LIBs) are widely used in various industries, especially in electric vehicles (EVs), due to their high energy density and exceptional cycle life. However, the sensitivity of their performance to cell temperature and thermal runaway issues pose challenges to their reliable and easy implementation, necessitating the early detection of thermal runaway. This experimental study investigates the early detection of thermal runaway triggered by overcharging at different charging rates. Throughout the entire process of thermal runaway under overcharge conditions, sensors were employed to assess various physical attributes such as surface temperature, voltage levels, and gas leakage from the batteries. The results indicate that thermal runaway occurs for all 1C, 1.5C, and 2C charging rates, with thermal runaway times at 2056 s, 1487 s, and 1037 s, respectively from the intial time. The surface temperature of the battery reaches its maximum peak at a charging rate of 2C, indicating that higher charging rates can lead to a faster and more severe thermal runaway. The charging rates also affect the gases (CO and CO2) produced during thermal runaway. During thermal runaway, a high-speed camera was used to capture the events. Finally, by closely monitoring the gas emissions during the initial phase of thermal runaway, the early detection of thermal runaway becomes attainable. When the battery was operating under a 1 C charging rate, sudden spikes in the CO2curve were observed about 500s before the thermal runaway, indicating that thermal runaway is about to occur. With successful identification of thermal runaway, a relay module or certain cooling strategies can be used to mitigate the thermal runaway.