Novel hybrid polymer composites for optimized thermal performance in electric vehicle battery cases

Electric vehicles are essential for ensuring the sustainability of transportation and have the advantage of emitting no environmentally harmful gases due to their non-reliance on fossil fuels, such as internal combustion engines. However, battery performance remains a significant barrier to wider use of electric cars, as the joule effect increases temperature, negatively impacting battery efficiency. The objective of this study is to create polymer-based hybrid composite materials that enhance the thermal conductivity and impact strength of the battery module. Polyamide 6 (PA6) was chosen as the matrix material because of its extensive usage and ease of fabrication. Hexagonal boron nitride (h-BN) and graphene nanoplatelets (GnPs) were used to enhance thermal conductivity. Furthermore, a Styrene-ethylene-butylene-styrene (SEBS) elastomer supplement has been included to enhance protection against probable ground impact damage. After production, samples underwent mechanical and thermal testing. The addition of GnPs led to an 8.9% enhancement in the elastic modulus and a 4.97% improvement in the tensile strength value. The results demonstrate that the thermal conductivity had a significant rise of 194.3% when 30% h-BN was incorporated based on weight. Subsequently, fracture surfaces were examined using a scanning electron microscope (SEM) to analyze the mechanisms that caused the damage. Afterwards, the thermal conductivity of the compositions was determined utilizing analytical methods and by creating a representative volume element (RVE). In the end, the compositions were evaluated based on several qualities, resulting in the selection of the most suitable composition by using the response surface method (RSM) and python-based optimization code. Highlights: Incorporating 30% h-BN into the neat matrix increased the thermal conductivity by 194.3%. Optimization studies showed that 30% h-BN reinforcement led to the most preferred results. GnP addition improved mechanical properties. GnP and h-BN reinforcements improve the composites' glass transition temperature.