From Aging-Dependent Lithium-Ion Cell Model to Operating Limit Definition: A Virtual Testing Framework for Power Capability Degradation

Reliable power capability estimation is essential for battery management systems (BMSs), yet aging progressively alters the admissible charge and discharge limits of lithium-ion cells. This paper presents an aging-aware framework combining the experimental identification of a first-order one-RC electrical equivalent circuit model, coupled with a lumped thermal model, with automated virtual current-step tests. The procedure determines the maximum admissible current under voltage and temperature constraints and generates charge and discharge power-limit maps as functions of State of Charge, temperature, State of Life, and pulse duration. The methodology is applied to four cylindrical NMC 18650 cells aged under different cycling conditions and is validated at selected operating points using a separate cell, with a median current error of 2.8%. From 100% to 70% State of Life, the domain-averaged State-of-Power reduction for 30 s pulses is approximately 30% in discharge and 50% in charge, the 70% level being extrapolated for three cells. At equal aging levels (90% and 80%), differences associated with the aging trajectory are smaller over the mid-State-of-Charge region and larger near the operating boundaries. The framework is intended for the offline generation and updating of BMS power-limit tables, reducing the experimental effort required at each aging stage.