This study is centered on exploring the characteristics of lithium cobalt oxide (LCO) batteries under low-temperature conditions and investigating the temperature fluctuations associated with thermal runaway events. Firstly, capacity tests were conducted at varying temperatures to compare the capacity retention rates of ternary lithium-ion batteries and LCO batteries at ?30 ℃. These tests revealed that LCO batteries nearly doubled their discharge capacity in comparison to ternary lithium-ion batteries at this temperature. Secondly, the internal resistance of the batteries was obtained by using the mixed-power pulse characterization test at different temperatures. Then, testing was conducted on the electrochemical impedance of LCO batteries under low-temperature conditions, revealing that at ?10 ℃, ?20 ℃, and ?30 ℃, the charge transfer impedance increases by 180%, 702%, and 2400%, respectively, compared to 0 ℃. Finally, a nail penetration experiment was executed on the LCO batteries and found that the maximum temperature of the battery surface was not more than 530 ℃ after a steel needle pierces the back of the battery, which was accompanied by a small amount of sparks. Subsequently, substantial smoke generation occurred without any indication of a fire event.