Bozunma sonrası ikinci yaşam uygulamaları için Li-Ion pil performansı üzerine deneysel bir çalışma

This thesis investigates the second-life framework potential of lithium-ion cells, emphasizing non-invasive approaches and state of health State of Health (SoH) modeling. The study begins with an analysis of the first life of batteries, covering manufacturing processes and the factors that determine their readiness for second-life applications. Battery assemblies are categorized into two groups: permanently connected systems, such as laser-welded or ultrasonically bonded, and non-permanent systems, such as bolted connections or mechanically secured cell beds. Non-permanent assemblies are identified as the most suitable for second-life applications, forming the foundation of a secondlife framework. To support this framework, efficient SoH estimation methods are developed and validated. Two models are proposed: a detailed model incorporating cycling conditions, charge rates, and depth of discharge Depth of Discharge (DoD), and a simpler model focusing on changes in DC internal resistance Direct Current Internal Resistance (DCIR)(%) value and cycle count. Both models demonstrate reliable SoH predictions, facilitating the effective sorting and reuse of cells without permanent interconnections. While the detailed model provides greater insights into cell aging, the simpler model offers practical advantages with lower testing requirements, making it suitable for scalable second-life applications. By validating these models under varied conditions, the study contributes to second-life methodologies by presenting adaptable, non-invasive estimation tools and scalable solutions for battery reuse.