Thermal characteristics of ultrahigh power density lithium-ion battery

Ultrahigh power density lithium-ion batteries (LIBs) are widely applied in transportation and energy storage systems. However, the thermal characteristics of power lithium-ion batteries under high discharge rates remain unclear. In this work, a commercial lithium-ion battery with lithium titanate oxide (LTO) as the anode material is investigated under discharge rates up to 40C. The heat generation power and temperature rise ratio increase with the discharge rate. A maximum heat generation rate of 358 W is obtained under 40C discharge. Due to the limited discharge capacity with high discharge rates, the highest temperature rise appears under 25C discharge, which is 38.9 degrees C. The percentage of irreversible heat increases with the discharge rate, but it only accounts for 83% under 40C discharge. Furthermore, different internal resistance estimation methods are used to predict the heat generation of lithium-ion batteries. It is found that hybrid pulse power characteristic (HPPC) method is more accurate than electrochemical impedance spectroscopy (EIS) method, and heat generation in higher discharge rate can be estimated by HPPC with a shorter time scale.