Pack-Level Artificial Ageing of Automotive Pouch Cells: Electrical and Mechanical Comparison with Real Aged References

This study evaluated whether artificial ageing at the complete-pack level can reproduce selected electrical and mechanical characteristics of pouch cells aged in vehicle operation. A two-phase procedure combined Worldwide Harmonized Light Vehicles Test Cycle (WLTC)-derived loads with commanded 2C recharging under active BMS current limitation while retaining the original battery management and liquid-cooling systems. Across 300 charging events, 1860 WLTC-based profiles were completed, corresponding to an estimated 114 energy-based full equivalent cycles and 43,300 km of WLTC-equivalent driving. Extracted cells were compared with fresh and real aged reference cells from 160,000 km of vehicle operation using electrical characterization and quasi-static indentation at 100% state of charge. Five health indicators comprised charge- and discharge-based state of health, coulombic efficiency, and two capacity-to-voltage slopes over the 45–32 Ah and 32–19 Ah intervals. Agreement between the electrical indicators was metric-dependent, with close agreement in charge-based state of health and the slope between 45 and 32 Ah. Artificially aged and real aged cells showed comparable mean maximum indentation forces (43.5 versus 42.5 kN) and ISC-onset displacements (2.100 versus 1.991 mm) under the investigated test conditions. Selected characteristics were reproduced after 27% of the reference mileage, corresponding to a distance-based acceleration factor of approximately 3.7.