Comparative Analysis of EV Battery Degradation: Real-World Data vs. Lab Simulations

This paper investigates discrepancies between electric vehicle (EV) battery degradation observed in real-world usage and predictions from lab simulations. While lab testing typically assumes consistent, full charge-discharge cycles under controlled conditions, real-world EV operation introduces variable charge states, sporadic Depth of Discharge (DoD), and temperature fluctuations due to driving behaviors such as acceleration and braking. Using real-world data from Stanford University [1] alongside lab simulation data, this study analyzes how these factors accelerate degradation in actual usage scenarios compared to lab predictions. Findings reveal that real-world factors significantly reduce battery lifespan and performance, challenging the reliability of lab-based models for predicting EV battery longevity. This work suggests adaptations in lab methodologies to incorporate variable State of Charge (SoC), DoD, and temperature fluctuations, which could improve the accuracy of battery management systems and extend practical battery life in EV applications.

I. Introduction

Electric vehicles (EVs) rely on lithium-ion batteries for power storage, making battery health a critical factor in the performance, range, and lifecycle of EVs [2]. As the adoption of EVs grows, understanding and accurately predicting battery degradation has become essential for both manufacturers and end-users [3], [4]. Battery degradation not only affects the capacity and efficiency of the vehicle but also impacts the cost of ownership and the sustainability of EV technology. Consequently, the development of reliable models to forecast battery lifespan and manage its health is a high priority in EV research [5]. The transition to electric vehicles (EVs) is rapidly advancing across the globe, driven by rising concerns over climate change, government regulations on emissions, and shifting consumer preferences toward cleaner, more sustainable transportation. In recent years, EV adoption rates have surged, with global EV sales exceeding expectations across major markets like the United States, Europe, and China. This growth has been fueled by both policy incentives, such as tax rebates, EV purchase subsidies, and stricter emission standards, and technological advancements that have increased EV affordability, efficiency, and range. As EVs continue to move from niche products to mainstream transportation options, their penetration into the global market is expected to accelerate even further.