Uğur Morali

Phase change material (PCM)‐based thermal management systems have attracted considerable attention for controlling the thermal behaviour of lithium‐ion batteries operating under high discharge‐rate conditions. However, the inherently low thermal conductivity of conventional PCMs limits their thermal regulation capability, while previous studies on expanded graphite (EG)‐enhanced composite PCMs have mainly focused on thermal conductivity enhancement and maximum temperature reduction. Limited attention has been paid to the combined effects of EG concentration and CPCM thickness on temperature uniformity, volumetric energy density, and techno‐economic optimization under different operating conditions. In this study, an EG‐integrated composite phase change material (CPCM) based on RT44HC was numerically investigated for the thermal management of cylindrical lithium‐ion batteries. A comprehensive parametric analysis was conducted to evaluate the coupled influences of EG concentration, CPCM thickness, and discharge rate on battery thermal behaviour. The results showed that increasing CPCM thickness significantly reduced battery temperature, whereas the influence of EG concentration exhibited a more complex thermal response due to the competing effects of enhanced thermal conductivity and reduced latent heat capacity. RT44HC20 with the 12.5 mm thickness was identified as the optimum configuration based on a multi‐objective evaluation considering thermal performance, temperature uniformity, volumetric energy density, system mass, and economic feasibility simultaneously. RT44HC20 maintained the battery temperature below the critical threshold of 40°C while also providing improved temperature uniformity and lower material cost. The findings provide practical design guidance for the development of lightweight, cost‐effective, and thermally efficient CPCM‐based battery thermal management systems for high‐power lithium‐ion battery applications.

Lithium-ion batteries, widely used in electric vehicles, play a complex yet overall positive role in mitigating global warming [1,2]. One of their primary advantages is the ability to significantly...

Lithium‐ion batteries play a crucial role in reducing carbon emissions and promoting the use of electric vehicles. There are numerous input variables influencing the thermal profile of lithium‐ion batteries. Therefore, a precise assessment of the relative contributions of various factors is essential for optimizing thermal management and control processes. In this study, we tested a lithium‐ion battery pack composed of five 14.6 Ah prismatic cells connected in series under different discharge rates (2C, 3C, 4C, and 5C), ambient temperatures (30, 35, 40, and 45°C), and convective heat transfer coefficients (5, 10, 20, and 40 ). Results showed that the ambient temperature with a contribution of 58.01% had a strong influence on the maximum battery pack temperature. Furthermore, the influences of discharge C‐rate and convective heat transfer coefficient on the maximum battery pack temperature were identical. Moreover, it was found that the homogeneousness of the battery pack was very sensitive to the discharge C‐rate, contributing 71.07% to the increase in temperature difference. To ensure battery pack temperature and temperature uniformity at the same time, moderate ambient temperatures, low discharge C‐rates, and high convective heat transfer coefficients can be preferred. Consequently, the statistically obtained results in this study may contribute towards performance optimization and improved thermal safety of lithium‐ion battery packs.

Phase change material cooling method as a zero energy consumption cooling system has a good prospect in battery thermal management systems. Therefore, the thermal response of the lithium‐ion battery in the presence of a phase change material was explored in this study. The lithium‐ion battery was subjected to high discharge conditions (5 C‐rate) at high ambient temperatures (35°C and 40°C). The results showed that the usage of phase change materials with a thickness of 1 mm can reduce battery temperature and deliver a better temperature difference in a lithium‐ion battery. Results also revealed that for a 14.6 Ah lithium‐ion battery under a 5 C discharge rate, a phase change material cooling system with a thickness of 1 mm can reduce the maximum temperature from 51.64°C at 35°C and 55.85°C at 40°C ambient temperatures (without phase change material) to 43.04°C and 43.81°C, respectively. It was concluded that the phase change material system with a thickness of 1 mm can manage the maximum battery temperature and temperature difference in the desirable range at an extreme discharge rate of 5 C. The results obtained from this study can be used as guidance in the design of battery thermal management systems including phase change materials.

In the current study, the impact of C-ratio, convective heat transfer coefficient, and free stream temperature on the maximal cell temperature and temperature uniformity was computationally and statistically examined. Results revealed that the free stream temperature was the main influential factor for the maximal cell temperature for both natural and forced convection conditions while the C-ratio was the most effective parameter for the temperature uniformity for both natural and forced convections. On the other hand, the contribution of the free stream temperature to the maximum battery temperature increased from 63% to 94% when the conditions were changed from natural convection to forced convection. Moreover, the contribution of the C-rate to the temperature uniformity decreased from 89% to 79% when the conditions were changed from natural convection to forced convection. The results obtained from this study are significant in terms of determining which factor should be given more importance under natural and forced convection conditions.

In this study, a comprehensive simulation study was carried out to obtain detailed battery temperature behaviors. The influences of air inlet temperature, air flow rate, C‐rate, and free stream temperature were investigated on the temperature uniformity and maximal battery temperature. Taguchi design is implemented to investigate the main effects of four control parameters in the battery thermal management process. Results indicated that as the free stream temperature (delta = 7.3366) was the most influential factor for the temperature uniformity, the air inlet temperature (delta = 0.2679) was the most efficient factor for the maximal battery temperature. The contribution of the air inlet temperature was 28% and 38% for temperature uniformity and maximal battery temperature, respectively. Additionally, the free stream temperature contributed 32% to temperature uniformity and 25% to the maximum battery temperature. The airflow rate was found to be the least effective factor for temperature uniformity (delta = 2.8672) and maximal battery temperature (delta = 0.0506). The results could be helpful in the design of a lithium‐ion battery thermal management process to improve temperature uniformity and maximal battery temperature.