Evaluation of convective heat transfer coefficient and specific heat capacity of a lithium-ion battery using infrared camera and lumped capacitance method

The electrochemical performance of lithium-ion batteries is highly temperature dependent. An accurate determination of battery thermal parameters is crucial for research including cell thermal analysis, safety design, and multiphysics simulations. This work explores the possibility to use a lumped capacitance model based experimental approach to measure the battery convective heat transfer coefficient and specific heat capacity. In this approach, the transient temperature of the battery and its can (by removing the jellyroll) is measured with an infrared radiation camera. When the Biot number of the battery Bi << 1, the lumped capacitance model can be used to determine cell specific heat capacity through the measured battery surface temperature, where the convective heat transfer coefficients of both the can and the battery are the same and the specific heat capacity of the can is known. As an example, the specific heat capacity of LG G5 smartphone batteries is measured to demonstrate the proposed approach. The specimens are tested under both natural and forced convection conditions. The measured cell specific heat capacity is very consistent between these two convection conditions.