Probing the Anisotropic Thermal Conductivity in Lithium-Ion Polymer Batteries

Lithium-ion batteries (LIBs) play a pivotal role in the function of rechargeable battery systems and popular electronics like cell phones and electric vehicles. However, LIB cells encounter safety issues and can combust if they lack proper thermal management. Thermal conductivity is an essential measurement in designing batteries that mitigate safety concerns. In this experiment, data were collected to account for through-plane and in-plane thermal conductivity using a novel setup consisting of a Wheatstone Bridge, current source maintenance circuits, and a flexible h eater. Thermal conductivity m easurements were determined to be $1.57 \mathrm{~W} / \mathrm{mK}$ for through-plane and $24.88 \mathrm{~W} / \mathrm{mK}$ for in-plane, indicating that the layered structure of the throughplane of a battery significantly r educes t hermal conductivity. These results indicate the importance of prioritizing cooling and heating systems within the dimension of highest thermal conductivity, in-plane, for future thermal management strategies.