Battery Electric Vehicle Energy Efficiency: Systematic Review and Meta-Analysis of Enabling Technologies

Improving the energy efficiency of electric vehicles (EVs) remains a critical pathway to enhancing driving range, reducing battery size, and minimizing upstream emissions. This study presents a comprehensive review and meta-analysis of emerging and commercialized EV technologies, evaluating their impact on energy efficiency across five domains: vehicle body modifications, energy recuperation, thermal management, energy storage systems, and powertrain efficiency. A structured methodology was employed using the DerSimonian-Laird random-effects model, supported by hypothesis-based moderator variables, to synthesize effect sizes from simulation studies, real-world data, and industry claims. Results indicate that vehicle lightweighting and aerodynamic optimization yield average efficiency gains of 9% and 7%, respectively. Regenerative braking and vibrational energy harvesting contribute 4% and 5% improvements, while thermal management strategies such as cabin conditioning show up to 10% enhancement potential. Advances in battery technology—specifically solid-state and new chemistries have demonstrated gravimetric energy densities exceeding 400 Wh/kg. Powertrain advancements using wide-bandgap semiconductors and high-efficiency motors further elevate drivetrain efficiency beyond 90%. The heterogeneity across studies, captured via \((\tau^2)\), was addressed through moderator-based variance assignment. This paper delivers a scientific synthesis of energy optimization strategies for EVs and provides a robust foundation for selecting technologies based on impact, readiness, and implementation feasibility. These findings support stakeholders and policymakers in prioritizing investments that promote sustainable transportation outcomes.