Summary
In this study, a three‐dimensional numerical model is developed to investigate the thermal and electrical characteristics of 18 650 lithium‐ion battery cells that are used in the solar racing car of Dokuz Eylül University, i.e., SOLARIS. The Newman, Tiedemann, Gu, and Kim (NTGK) battery model of ANSYS Fluent software is implemented to resolve the coupled multiphysics problem. In the analysis, only the discharging period of the battery is considered. Before going through parametric studies under variable weather conditions, time‐wise variations of the cell temperature and the battery voltage are evaluated both experimentally and numerically under two different ambient conditions of 0°C and 25°C. Comparative results revealed that reasonable predictions are achieved with the current battery model, and the difference between the predicted battery surface temperature and experimental data is less than 1°C. Following the model validation, the battery performance is numerically examined by applying the battery model to a real race procedure of SOLARIS. Phase change materials (PCMs) with different amounts and melting temperatures are implemented around the batteries, and transient analyses are conducted under real weather conditions. The current study aims to keep the battery temperature of a solar racing car above a certain limit to prevent the overcooling and maintain higher charging capacity. Implementation of PCM with a melting temperature of 26°C yields 3.15% of capacity increment, and such a performance improvement corresponds to 15.51 Wh of extra energy that can be extracted from an individual battery.
Synthesis of positive electrode materials for lithium ion batteries (LIB) plays a major role in battery performance. In this study, we first investigated the effect of chelating agents and calcination temperature on the production of LiNi0.8Co0.2O2 cathode material. Then, by using mechanical mixing and sol-gel methods, tin oxide was introduced in the LiNi0.8Co0.2O2 powder to enhance the electrochemical performance. The effects of chelating agents (citric acid, oxalic acid, adipic acid), calcination temperature (600-800 °C, @10 hours) and the tin oxide presence on the LiNi0.8Co0.2O2 powders were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Brunauer, Emmmett and Teller (BET) analyses. Galvonastatic tests were performed in between 3-4.2 V at various C rates (0.2, 0.5, 1C).The powders produced by using adipic acid as chelating agent at 700 °C showed higher capacity and better electrochemical properties than those of powders synthesized by oxalic and citric acid. And sol-gel modified powders had higher initial capacity and better capacity retention than the mechanically modified and the bare powders. Sol-gel modified powders had more stable cycle characteristic and they had not shown immediate capacity fall even at higher C rates where they kept their capacity above 140 mAh/g even after 50 cycles.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.