Lab-to-field gap in battery aging studies: Mismatch of operating conditions between laboratory environments and real-world automotive applications

In response to the growing demand for electric vehicles, ensuring the longevity of traction batteries has become a central focus of scientific research. While most aging studies rely on accelerated aging testing with tightened stress factors, real-world battery operation reveals fundamentally different load profiles and aging conditions. To disclose the gap between the laboratory and the real-world application, we collected and assessed almost 2600 stress factor combinations from 201 different calendar and cycle aging studies. Moreover, we gathered and analyzed vehicle data from over 72 000 km of everyday usage of seven vehicles in public road traffic in Germany and extracted the related battery-specific load spectra. The stress factor combinations chosen in the literature show a trend towards high temperatures and state of charges (SOCs) during storage in calendar aging studies. In contrast, cycle aging tests are predominantly performed at full depth of discharge (DOD) or elevated average SOC levels, with current rates of primarily ± 1 C at 25 °C or slightly elevated temperatures. Contrary to this, the field data analysis reveals the following main findings: Driving events rarely exceed 30 km in distance or 40 min in duration, with an average driving speed of 61.1 km h − 1 . This leads to average current rates of − 0.2 C in discharging and 0.1C in charging direction and average cycle depths of less than 30%, while the average battery pack temperature ranges around 17 °C. Comparing laboratory test conditions with stress conditions in field applications reveals three major discrepancies: First, the stress levels applied are substantially higher than the stresses acting in real-world operation. Second, the dynamic load characteristic of real-world vehicle operation is rarely reflected; most studies work with synthetic constant current load cycles. Third, intermediate rest periods, which are predominant in real-world use, are omitted in most studies. This raises concerns about the transferability and applicability of findings from accelerated aging tests to automotive real-world applications. • Review and analysis of 2600 test points from 200 + accelerated aging studies. • Analysis of 72 000 km of field data from 4821 vehicle operations over 38 months. • Revealing a substantial mismatch between laboratory test and real-world stresses. • Full dataset available open access, including HV battery, drivetrain, and odometry.