Novel Calibration Approach of a Zero-Order Equivalent Circuit Model for Lithium-Ion Batteries

Accurate and computationally efficient battery modeling is essential for the design and control of advanced energy storage systems. This work introduces a novel calibration approach for a zero-order Equivalent Circuit Model (ECM) of lithium-ion batteries, relying solely on constant-current (CC) discharge tests to characterize the cell open-circuit voltage and internal resistance, thereby eliminating the need for time-consuming pulsed methods while intrinsically integrating temperature-dependent effects. The proposed zero-order ECM is validated through experimental tests on a 26650 cylindrical LFP cell under both static and dynamic load profiles, and its performance is benchmarked against zero and second-order ECMs calibrated with conventional Basic Pulsed and Multi-rate Hybrid Pulse Power Characterization techniques. Results demonstrate that the proposed approach achieves superior accuracy under load conditions, often outperforming second-order ECMs, while significantly reducing testing time and calibration effort. This highlights its suitability for applications requiring fast, reliable, and cost-effective model development.