Identifying Heat-Critical Zones in EV Power Cable Systems Under Load Conditions

The increasing power demand and fast-charging requirements of electric vehicles (EVs) intensify the need for robust thermal management, particularly in high-current power cable systems. This study aims to explore which cable components are most susceptible to thermal stress under operational loads. A full-scale laboratory test bench was developed, featuring a brushless DC motor, battery pack, controller, and digital monitoring system. Thermal data were collected using a thermal imaging camera across key components including the motor cable, main switch, and connectors, while electrical data such as current, voltage ratio, and battery capacity ratio were also recorded. The results identified the connector as the most thermally critical component, reaching a maximum of 47°C, followed by the Power cable (+) after Main switch at 41.2°C, the Motor cable at 39.7°C and Main switch at 36.5°C. Electric current was found to be the primary driver of temperature rise, with Pearson correlation coefficients of 0.82 for the motor cable, 0.78 for the main switch, and 0.76 for the connector. Meanwhile, battery capacity ratio and voltage ratio values were moderately correlated with higher temperatures, showing inverse correlations ranging from -0.55 to -0.71. These findings validate electro-thermal theory and underscore the role of resistive heating in EV cable components. The study offers a structured diagnostic framework to prioritize thermal risk in cable systems and informs future efforts in thermal modelling and system design. It contributes actionable insights for improving thermal resilience in electric powertrains and sets the stage for further exploration of active cooling strategies and material innovations.