The characterisation of lithium-ion battery cells is becoming an increasingly prominent area of focus within both academic and industrial sectors. This reflects the growing reliance on this technology for a diverse range of applications, including the storage of green energy and the advancement of electric mobility. The determination of the thermal behaviour of batteries is crucial for their safe, reliable and long-term operation. Furthermore, variation in temperatures within the battery cell is reported to induce internal mechanical stresses. Cell manufacturers typically design and construct cells based on the known thermal characteristics of the battery components. The currently used simulation technologies and material models are mostly based on phenomenological observations of the whole cell and can only reproduce the complex behaviour of battery cells under multiaxial mechanical and thermal load effects to a certain degree. To be able to predict the behaviour of the battery cell more accurately, detailed layer-resolved battery models should incorporate anisotropic mechanical and thermal material properties to account for the differences in behaviour along different axes. However, such detailed models need comprehensive material data of the individual battery cell components.
This study focuses on the measurement and evaluation of thermo-physical properties of the anode and cathode layers of a Li-ion battery cell; namely the in-plane coefficient of thermal expansion (CTE) and the thermal diffusivity of each layer using the Dantec Q400 system and a Laser Flash Analyzer (LFA), respectively. Varying behavior has been observed depending on the location of the cut specimen in the CTE measurements conducted for the anode and cathode materials. Therefore, a grid of nine samples has directly been cut from the extracted material foils of a commercial Li-ion battery cell and the CTE of the respective material has been determined by a least-squares fit to the measured data. Thermal diffusivity of each material has also been evaluated as a function of temperature.