With the rise of EVs, researchers are focusing on optimizing busbar design to meet the demands of high energy density, fast charging, and compact battery packs. The busbar design starts by selecting the material and the cross-sectional area required based on the rated current requirement. The width matches or may exceed the battery cell terminal size, whereas the length is optimized such that it is packaged within the given space constraints. The research also highlights the risk of busbars to oxidation and corrosion, which increases resistance and decreases conductivity for which plating/coating techniques are applied to improve the surface finish, overall durability, conductivity and in some cases the surface hardness, while minimizing the heat loss. Using simulations and experimental validation, the study examines three key design parameters: the weld diameter for busbar welded joints, electrical resistance, and contact resistance. A detailed analysis investigates how the weld diameter influences the electrical resistance and temperature rise over ambient and the impact of contact resistance between busbars and battery cell terminals on energy efficiency and thermal behavior. The above parameters if not designed and optimized may create a bottleneck in achieving a higher performance which the cells can deliver but it will be limited because of an uneven current distribution, higher heat generation and busbar temperatures exceeding the limiting values. This makes the busbars a critical component in the battery pack design for achieving the desired performance as well as reducing concerns of overall battery safety. This study highlights the importance of an optimized busbar design for creating safer, more efficient, and reliable EV battery packs by addressing key thermal and electrical challenges.