WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7150
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Review Citation - WoS: 13Citation - Scopus: 18Review of Cell Level Battery (calendar and Cycling) Aging Models: Electric Vehicles(Mdpi, 2024) Yarimca, Gulsah; Çetkin, Erdal; Cetkin, Erdal; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyElectrochemical battery cells have been a focus of attention due to their numerous advantages in distinct applications recently, such as electric vehicles. A limiting factor for adaptation by the industry is related to the aging of batteries over time. Characteristics of battery aging vary depending on many factors such as battery type, electrochemical reactions, and operation conditions. Aging could be considered in two sections according to its type: calendar and cycling. We examine the stress factors affecting these two types of aging in detail under subheadings and review the battery aging literature with a comprehensive approach. This article presents a review of empirical and semi-empirical modeling techniques and aging studies, focusing on the trends observed between different studies and highlighting the limitations and challenges of the various models.Article Citation - WoS: 5Citation - Scopus: 5An Experimental and Comparative Study on Passive and Active Pcm Cooling of a Battery With/Out Copper Mesh and Investigation of Pcm Mixtures(Elsevier, 2024) Samancioglu, Umut Ege; Çetkin, Erdal; Gocmen, Sinan; Madani, Seyed Saeed; Ziebert, Carlos; Nuno, Fernando; Huang, Jack; Cetkin, Erdal; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThe carbon emission contribution to global warming accelerated both research on and transition to electric vehicles (EVs). Drivers demand high power, fast acceleration and less charging times. All these demands require high C rate charging/discharging demands from batteries. The rate of heat generation is exponentially proportional to C rates which decreases battery lifetime and may lead to thermal runaway. However, a battery thermal management system decreases thermal runaway risk and decelerates battery degradation via controlling battery temperature. In this paper, we first document the thermal conductivity enhancement via copper foam into phase change material (PCM) domain to uncover their possible use in EV thermal management applications. Maximum 15.93 times increment is achieved with a specific copper foam. Then, physical properties and behaviors of distinct PCM mixtures are documented. Homogeneity of mixtures is associated with the chemistry of PCMs and the mixture melting point is proportional to the volume weighted average of melting temperatures. The results document that the PCM with relatively lower melting point is beneficial when end of discharge temperatures considered, except for high discharge rate of 2C. Temperature uniformity across the battery increases with relatively higher melting point PCM. Experiments also document that the amount of PCM volume lost via insertion of copper foam yields higher end of discharge temperatures. Overall, both PCM and copper foam enhances temperature homogeneity and their benefit becomes more sensible during drive cycles relative to continuous charge/discharge use cases.Conference Object Liquid Cooling of Li-Ion Cells Based on a Constructal Canopy-To Approach(Amer Soc Mechanical Engineers, 2024) Gungor, Sahin; Çetkin, Erdal; Cetkin, Erdal; Lorente, Sylvie; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyWhile many countries ambition to transition to clean energy, challenges appear related to the new developed technologies. This is particularly the case when it comes to electric vehicles and their batteries. The technology of the latter is based on Lithium-ion electrochemical reactions. During the batteries discharge, the electrochemical reactions are exothermic, and they are endothermic during the charging phase. The large change in temperature threatens the life duration of the batteries, and when combined to other factors, their safety. Therefore, the thermal management of the electric vehicle battery pack is a critical aspect that requires specific attention. In this paper, we present the work conducted by our group on thermally efficient solutions for maintaining the battery cells within the temperature range expected by manufacturers. The thermal management solution consists in inserting between the battery cells a constructal-based liquid cooling system. Such systems are called canopy-to-canopy architectures. The cooling fluid is driven from a trunk channel to perpendicular branches that make the tree canopy. An opposite tree collects the liquid in such a way that the two trees match canopy-to-canopy. The results indicate that such configurations allow to extract most of the non-uniformly generated heat by the battery cell during the discharging phase, while using a small mass flow rate. Furthermore, the configuration with 5 branches appears to be the one with high thermal efficiency and low pumping power.Article Citation - WoS: 2Citation - Scopus: 2Optimization of Y-Shaped Micro-Mixers With a Mixing Chamber for Increased Mixing Efficiency and Decreased Pressure Drop(Asme, 2024) Samancioglu, Umut Ege; Çetkin, Erdal; Kosar, Ali; Cetkin, Erdal; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyIn this study, Y-shaped micromixers with mixing chamber design optimized as rotation and chaotic advection in the fluid domain increase with the chamber. Motivated by the advantages of Y-shaped mixers, a parametric study was performed for inlet angles (alpha, beta), inlet channel eccentricities (x-ecc, z-ecc) and length scale ratios (L-1/L-2, D-1/D-2, and V-sp). z-eccentricity is introduced in addition to x-eccentricity to create a design that further enhances the swirl and chaotic advection inside mixing chamber for the first time. The results reveal that the maximum mixing efficiency can be achieved for Reynolds number of 81 and alpha, beta, x-ecc, z-ecc, D-1/D-2, and L-1/L-2 values of 210 degrees, 60 degrees, 20 mu m, 20 mu m, 1.8, and 4, respectively. In addition, the proposed Y-shaped micromixer leads to a lower pressure drop (at least 50% reduction for all Reynolds numbers) in comparison to competing design. The maximum reduction in pressure drop is 72% less than the curved-straight-curved (CSC) (Re = 81) with mixing efficiency of 88% and pressure drop of 9244.4 Pa. Overall, an outstanding mixing efficiency was offered over a wide range of Reynolds numbers with distinctly low pressure drop and a compact micromixer design, which could be beneficial for a wide variety of applications where volume and pumping power are limited.