Anisotropic Thermal Conductivity of Lithium‐Ion Batteries at the Full‐Cell Level: A Review of Methodology Advances, Data Analytics, and Future Applications

The knowledge of anisotropic thermal conductivity of lithium-ion batteries (LIBs) is paramount for accurate battery thermal modeling and diagnosis because of its decisive influence on the internal temperature distribution and overall thermal behaviors of LIBs. However, due to the complex materials, geometries, and dynamic state variations of LIBs, obtaining accurate anisotropic thermal conductivity at the full-cell level remains challenging. Here, a comprehensive review is provided on the latest methodologies and data analytics of the anisotropic thermal conductivity of battery cells with different chemistries and geometries under dynamic operating conditions. The applicability, uncertainty, advantages, and limitations of current measurement methods are examined, providing guidance for method selection and future improvement. The anisotropic thermal conductivity data across various cell formats and electrode materials are evaluated, and their variations with temperature, state of charge, state of health, and charge/discharge rates are analyzed. Additionally, future applications are highlighted for thermal conductivity to serve as a key input for thermal modeling and an indicator for battery diagnostics, with the development of in situ and real-time measurement methods and artificial-intelligence-driven models. These efforts collectively support an integrated framework for next-generation thermal management systems toward improving the performance, safety, and lifespan of LIBs and other emerging batteries.