Influence of latent heat based passive cooling on the performance of EV battery under automotive drive cycles

The utilisation of passive cooling techniques involving Phase change materials (PCMs) represents a promising approach in the realm of battery thermal management systems (BTMS). Specifically, this study delves into the examination of a single cylindrical Panasonic 18650 battery cell, employing a circumferential Latent Heat (LH) jacket, under various real-world automotive drive cycles. The challenge addressed in this research revolves around understanding the impact of haphazard behaviour in the battery’s performance and thermal stability in the presence of proposed passive cooling. While drive cycle data, encompassing aggressive to casual driving scenarios, has been collected, there remains a need to evaluate how these driving behaviours affect the battery’s performance and longevity. To address this issue, this study uses conjugated thermo-chemical and electrical models of the battery. These models are informed by numerically simulated results based on real-world driving scenarios that account for varying routes, driving styles, and distances. The simulations were conducted at an ambient temperature of 25 °C and a 1C-rate to assess the impact of LH jacket usage on the battery’s performance under diverse drive cycles. The results reveal that the implementation of a LH jacket can significantly enhance the battery’s performance across multiple drive cycles. The data indicates an improvement of over 50% in the performance of the majority of drive cycles assessed. This enhancement is most remarkable in aggressive drive cycles, with battery life extending 2.2x to 2.4x times. The findings demonstrate that LH jackets maintain the battery’s thermal stability within the optimal range for more extended periods, mitigating sensible heat dominance until the PCM material reaches its full melting point. The study reports over a 45% thermal performance enhancement for all drive cycles examined, from aggressive to casual, and a life extension of more than 200% due to the delayed effect of the LH jacket. This methodological approach is of utmost importance as it significantly contributes to understanding and improving BTMS in real-world drive scenarios, especially concerning passive cooling through LH jackets.