A Novel Method for Determining the Specific Heat Capacity of Cylindrical Li-Ion Batteries

This study presents a novel and accessible method for determining the specific heat capacity of cylindrical lithium-ion batteries without the need for specialized equipment for cell disassembly, climatic chambers, or expensive calorimeters. The proposed approach does not require disassembly of the cell. Since specific heat capacity is a key parameter in thermal modeling and is often unavailable in manufacturer datasheets, the method addresses an important practical gap. The measurement principle is based on recording the change in surface temperature caused by a short 30 s discharge pulse of 9 A. A thermographic camera captures infrared images at fixed time intervals, while an electromechanical module rotates the battery around its longitudinal axis, providing an accurate estimation of the average surface temperature during and after the pulse. The resulting temperature–time profiles are used to evaluate heat losses and compute the specific heat capacity. To validate the methodology, experiments were conducted on an aluminum cylinder of identical dimensions to an 18650 cell, made of Al 6082-T6 (Cp ≈ 896 J·kg−1·K−1). The results show a maximum deviation of 2.68% from the reference value, confirming the reliability of the proposed method for determining the specific heat capacity of cylindrical Li-ion batteries.