Sequino Luigi, Sebastianelli Gaetano, Vaglieco Bianca Maria
Istituto di Scienze e Tecnologie per l'Energia e la Mobilità Sostenibili-CNR, 80125 Napoli, Italy.
Materials (Basel). 2022 Nov 3;15(21):7744. doi: 10.3390/ma15217744.
The increment of battery temperature during the operation caused by internal heat generation is one of the main issues to face in the management of storage systems for automotive and power generation applications. The temperature strongly affects the battery efficiency, granting the best performance in a limited range. The investigation and testing of materials for the improvement of heat dissipation are crucial for modern battery systems that must provide high power and energy density. This study presents an analysis of the thermal behavior of a lithium-polymer cell, which can be stacked in a battery pack for electric vehicles. The cell is sheltered with layers of two different materials: carbon and graphene, used in turn, to dissipate the heat generated during the operation in natural convection. Optical diagnostics in the infrared band is used to evaluate the battery surface temperature and the effect of the coatings. Experiments are performed in two operating conditions varying the current demand. Moreover, two theoretical correlations are used to estimate the thermal parameters of the battery with a reverse-logic approach. The convective heat transfer coefficient h and the specific heat capacity c of the battery are evaluated and provided for the Li-ion battery under investigation for different coatings' conductivity. The results highlight the advantage of using a coating and the effect of the coating properties to reduce the battery temperature under operation. In particular, graphene is preferable because it provides the lowest battery temperature in the most intense operating condition.
运行过程中由内部发热导致的电池温度升高是汽车和发电应用储能系统管理中面临的主要问题之一。温度会强烈影响电池效率，电池在有限的温度范围内性能最佳。对于必须提供高功率和能量密度的现代电池系统而言，研究和测试用于改善散热的材料至关重要。本研究对一种锂聚合物电池的热行为进行了分析，这种电池可堆叠成电动汽车的电池组。电池用两层不同材料（依次为碳和石墨烯）进行包覆，以在自然对流中消散运行过程中产生的热量。利用红外波段的光学诊断技术来评估电池表面温度和涂层的效果。在两种不同电流需求的运行条件下进行了实验。此外，使用两种理论关联式通过反向逻辑方法估算电池的热参数。针对所研究的锂离子电池，评估并给出了不同涂层电导率下的对流换热系数h和比热容c。结果突出了使用涂层的优势以及涂层特性对降低运行中电池温度的影响。特别是，石墨烯更具优势，因为在最强烈的运行条件下它能使电池温度最低。
