Challenges of the Measurement of the Effective Thermal Conductivity of Battery Electrodes with Laser Flash Analysis and Guarded Hot Plate Method

The thermal conductivity of battery components has become an important factor for predicting the temperature distribution within battery cells during their operation. The importance of this increases with a growing cell size and is especially important for prismatic hard case cells. However, its determination is still in an early stage, and different measurement approaches provide largely varying results. Herein, the thermal conductivity of electrode coatings is investigated by measuring the through‐plane thermal conductivity of electrode stacks. For this, the laser flash analysis (LFA) and guarded hot plate (GHP) method are used as common measuring approaches for battery components. A comparison of the different methods for different active materials, porosities, and electrode thicknesses is conducted and confirmed the strong variations between the two methods seen in the literature. Both methods have their challenges and limitations, where the most important is that LFA is best for thin and low‐porous electrodes and that the GHP is best for thick and high‐porous electrodes. The study discusses these and other effects around in greater detail.