Jiri Hvozda, Jan Bohacek, Alexander Vakhrushev, Ebrahim Karimi-Sibaki

Abstract: This study investigates the importance of considering the well-known spiral structure of cylindrical batteries in numerical models of heat transfer. Such models typically simplify the internal geometry by a concentric layout of electrodes and separators, resulting in an effective orthotropic thermal conductivity with radial, tangential, and axial components defined in a cylindrical coordinate system. However, the actual spiral structure suggests radius-dependent thermal conductivity. In this study, several thermal simulations were performed, comparing thermal fields obtained with the commonly used cylindrical orthotropy and a more realistic spiral structure. The results show that the spiral structure has a negligible effect on the overall temperature distribution for configurations with dense spirals and higher radial thermal conductivity (2 W·m−1·K−1). However, for lower radial thermal conductivity (0.2 W·m−1·K−1), considerable errors were observed even for dense spirals. These findings emphasize the need for studies to justify simplifications made in the thermal conductivity tensor.

Keywords: Battery thermal management systems, Li-Ion cylindrical batteries, orthotropic thermal conductivity, spiral structure.

Date Published: January 30, 2025
DOI: 10.11159/jffhmt.2025.003

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