One of our latest studies, Modeling Heat Transfer in Cylindrical Batteries: Spiral-Based Thermal Conductivity Tensor, explores how the internal spiral-shaped structure of Li-ion batteries affects the temperature field — and whether the commonly used simplifications in thermal models hold up under scrutiny.
Many models assume a concentric cylindrical layout of electrodes and separators, leading to orthotropic thermal conductivity with constant radial, tangential, and axial components.
But in reality, a tightly wound spiral is present inside the battery, suggesting position-dependent thermal behaviour.
What we found:
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At low radial conductivity (0.2 W·m⁻¹·K⁻¹), temperature deviations reached up to 7 °C compared to the spiral model
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With higher values (e.g., 2 W·m⁻¹·K⁻¹), the spiral had a negligible effect
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Simplified models are valid — but only when their limitations are understood
This study was conducted in collaboration with the Christian-Doppler Laboratory for Metallurgical Applications of Magnetohydrodynamics, Montanuniversitaet Leoben, Austria.
📖 Full article (Open Access):
https://jffhmt.avestia.com/2025/PDF/003.pdf
📌 Funding acknowledgement
The projects supported this work:
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“The Energy Conversion and Storage”, funded as project No. CZ.02.01.01/00/22_008/0004617 by Programme Johannes Amos Comenius, call Excellent Research
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“Hollow Fiber Heat Exchangers with Reduced Permeability for Smart Cities”, funded as project No. 8I24002 by Programme EIG CONCERT by the Ministry of Education, Youth and Sports