Module-Level Modelling Approach for Li-Ion Batteries: a Cloud-based Digital Twin Simulation Platform

• DIRECTORS: Dr. Eduardo Miguel Garcia de Cortazar and Dr. Unai Iraola Iriondo 
• UNIVERSITY: Mondragon Unibertsitatea

ABSTRACT

The adoption of large-scale Lithium-ion Batteries (LIBs) has been steadily growing. These installations involve interconnecting multiple batteries to create powerful systems capable of storing megawatt-hours (MWh) of energy. LIBs have emerged as a promising solution for electrical energy storage, thanks to declining prices and improved manufacturing efficiency. This accessibility has driven increased demand for LIBs in applications like electric vehicles and stationary systems. In the case of LIBs, particularly in module configurations, individual heterogeneities and imbalances among cells pose significant challenges. These disparities can compromise energy efficiency and overall lifespan of the battery module. While extensive studies have focused on individual cells, there remains a gap in understanding and addressing module-level effects and complexities. This thesis proposes an innovative methodology for developing module-level battery models that encompass thermal and electrical components, as well as a State of Charge (SoC) estimator. These models are derived from widely-used cell-level models using equivalent circuits. A detailed thermal model captures cell interactions within the battery system, while an electrical model simulates individual cell behaviour. An approach to implement these models in a cloud-based simulation platform enables performance estimations and issue identification. The proposed methodology has been validated through laboratory testing using a prototype. Tests demonstrate the accurate operation of the thermal and electrical models, as well as the SoC. In general, the proposed methodology in this thesis contributes to a better understanding allowing an adequate monitoring of the system.