Consideration of graphene material in PCM with aluminium fin structure for improving the battery cooling performance

The inner resistance of the battery increases over time with using. This increase means reduced battery life. The inner resistance's growth rate can be slowed down by a better battery thermal management system (BTMS). This will also extend the cycle life of the battery. The battery's performance is directly related to BTMS. Phase change material (PCM) based BTMS provide even heat distribution and lower maximum temperature. There are three types of PCM materials. These are organic PCM, Inorganic PCM and eutectic PCM. Organic PCM material was used, which should not contain this because inorganic PCM materials have corrosion exposure and organic PCM materials have low volume change. Since PCMs have high latent thermal energy storage capacity, they trap a high rate of heat in solid-liquid phase transitions. However, due to the low thermal conductivity of PCM, it has been tried to increase its thermal conductivity by using carbon, copper, graphene materials mixed with it. Graphene is used in many fields due to its superior properties. It was used in this study because of its high thermal conductivity. The aluminum fin material has a high surface area thanks to the fins on it. This maximizes the cooling performance. It has a high surface area thanks to the fins on the aluminium fin material. This maximizes the cooling performance. Graphene is a material with superior thermal conductivity. It has a high surface area thanks to the fins on the aluminium fin material. This maximizes the cooling performance. The use of the aluminium fin structure together with the PCM accelerates the heat transfer, thus allowing the battery to cool faster and lowering the maximum temperature value. In this study, three experiments with different structures were formed and the impact of graphene additive besides alüminium fin structure on PCM was observed. In all experiments, the temperature of the battery was observed by applying 4 charge-discharge cycles to the battery. The result demonstrates that, while no positive impact of graphene additive was observed in the first and third structures, the PCM-graphene additive between the alüminium fins of the structure used in the second experiment significantly improved the battery heat transfer by allowing the battery to cool down 1500 seconds earlier than the graphene-free structure. During this study, the method has been validated both experimentally and analytically. A thermal equivalent circuit model is derived for the second structure due to its successful demonstrated performance. It is observed that the model works accurately and shows its ability to control not only temperature fluctuations but also transient behavior of the battery. Also, this model provides the results in a short time. Thanks to this model, battery temperature can be observed without experimentation for different charge-discharge scenarios in lithium-ion batteries.