Experimental investigation of the design and performance of shaped-stable composite phase-change materials for the thermal management of lithium-ion batteries

With the development of technology, the need for energy is increasing day by day. The limited lifespan of fossil fuels, the environmental effects resulting from their use, and the lack of a uniform distribution of fossil resources around the world have led human beings to search for new ones. While this situation contributes to the spread of energy systems based on renewable energy sources, it is limited by the continuity problem that arises especially in systems based on solar and wind energy. In order to solve this problem, the use of energy storage technologies has attracted attention as an important alternative in recent years. The use of energy by storing allows use depending on the emergence of the need. In this context, latent thermal energy storage is one of the promising energy storage methods. With the new generation smart energy materials called phase change materials, energy can be stored in the form of latent heat. Another important option among energy storage technologies is power batteries that allow electrochemical storage. One of the factors affecting the operation of batteries, which have an important place in life, is temperature and therefore battery thermal management. In this thesis, it is aimed to design composite phase change materials to be used in the thermal management of Lithium batteries used in many fields including electric and hybrid vehicles. Thus, it is aimed to operate two known energy storage technologies as hybrids. Within the scope of the study, phase change materials compatible with the operating conditions of the batteries will be prepared and the production of composite energy materials compatible with the operating conditions will be realized. In addition, the designed composite energy materials was tested by preparing an experimental system and thermal performance of an Lithium ion battery was investigated. Among the capric acid/kaolinite composite PCMs obtained by one-step impregnation with different recipes, the highest thermal energy storage capacity was achieved with the composite PCM prepared by using 40% capric acid and 60% kaolinite, called CK40, and no leakage occurred in the obtained composite PCM. According to the analysis results, the peak melting temperature of the produced CK40 composite PCM was found to be Tpeak-melting= 33.47 ºC, and the thermal energy storage capacity was ΔHmelting= 73.07 J/g. Consequently, it has been experimentally shown that capric acid/kaolinite (CK40) composite PCM can be a suitable candidate for the thermal management of Lithium-ion batteries used in electric vehicles and can provide significant performance.