Experimental investigation of a passive battery thermal management system using phase change material and aluminium enhancements

Abstract

Efficient thermal regulation is critical for the safety and longevity of high-power energy storage systems. This study investigates the performance of a passive battery thermal management system (BTMS) for a 18650 module having 1200 mAh capacity at a nominal voltage of 3.7 V utilising OM42 phase change material (PCM) integrated with a high-conductivity aluminium fin structure. The experimental setup comprised a battery simulator enclosed in a transparent polycarbonate tube, with an automated data acquisition system controlled via Arduino UNO microcontroller. The thermal behaviour was evaluated across a range of discharge rates from 0.5 to 3C. To ensure statistical robustness, temperature data were recorded as the average of three internal thermocouples over three independent trials for each condition. The results demonstrate that PCM-fin integration effectively modulates peak temperatures, maintaining the system below critical thresholds, even at a maximum 3C rate (64 °C). A distinct phase change plateau was observed, confirming the PCM’s ability to absorb significant latent heat during exothermic operation. Post-operation cooling cycles showed consistent recovery to ambient levels within 80 min, validating the reliability of the system for cyclic use. These findings suggest that the proposed BTMS provides a sustainable and effective solution for mitigating peak temperatures, delaying thermal escalation, and enhancing the operational stability of high-power battery modules.