Enhanced Current Control and Preheating System for Tesla 4680 Battery Fast Charging: Multi-Temperature Performance Analysis and Energy Efficiency Validation

Fast charging of electric vehicle batteries faces significant thermal management challenges that limit charging speeds and battery longevity, particularly under extreme ambient conditions. This study develops and validates an enhanced electrothermal simulation framework for Tesla 4680 lithium-ion battery packs that integrates adaptive current control with temperature-dependent derating, state-of-charge tapering, and cold-weather preheating strategies. The framework employs a physics-informed equivalent circuit model with comprehensive temperature and SOC-dependent parameters, implementing realistic charging currents of 250A compared to the baseline 4-47A range. Validation across cold (-10°C), moderate (25°C), and hot (40°C) conditions demonstrates dramatic performance improvements: up to 2,430% increase in SOC gain under cold conditions without preheating, and 240% improvement at optimal temperatures, while maintaining peak cell temperatures below 60°C safety limits. The preheating system achieves positive energy economics with a 2.18:1 return ratio, enabling 40.84% SOC gain in 15 minutes during cold weather operation. Advanced current control delivers commercially viable charging speeds (86.63% SOC in 15 minutes at 25°C) that align with Tesla Supercharger specifications. The thermal analysis reveals excellent temperature uniformity (2-3K cell-to-cell variation) across the 65s2p pack configuration, with peak temperatures of 57°C under challenging hot weather conditions. The sophisticated multi-stage current tapering (250A→180A→120A→45A) effectively manages thermal stress while maximizing energy transfer efficiency. These results demonstrate the framework's potential to significantly reduce EV charging times, enhance battery longevity, and enable reliable fast charging across diverse climate conditions, supporting broader electric vehicle adoption and efficient high-power charging infrastructure integration into electricity grids.