Optimizing Average Electric Power During the Charging of Lithium-Ion Batteries Through the Taguchi Method

In recent times, lithium-ion batteries have been widely used owing to their high energy density, extended cycle lifespan, and minimal self-discharge rate. The design of high-speed rechargeable lithium-ion batteries faces a significant challenge owing to the need to increase average electric power during charging. This challenge results from the direct influence of the power level on the rate of chemical reactions occurring in the battery electrodes. In this study, the Taguchi optimization method was used to enhance the average electric power during the charging process of lithium-ion batteries. The Taguchi technique is a statistical strategy that facilitates the systematic and efficient evaluation of numerous experimental variables. The proposed method involved varying seven input factors, including positive electrode thickness, positive electrode material, positive electrode active material volume fraction, negative electrode active material volume fraction, separator thickness, positive current collector thickness, and negative current collector thickness. Three levels were assigned to each control factor to identify the optimal conditions and maximize the average electric power during charging. Moreover, a variance assessment analysis was conducted to validate the results obtained from the Taguchi analysis. The results revealed that the Taguchi method was an eff ective approach for optimizing the average electric power during the charging of lithium-ion batteries. This indicates that the positive electrode material, followed by the separator thickness and the negative electrode active material volume fraction, was key factors significantly infl uencing the average electric power during the charging of lithium-ion batteries response. The identification of optimal conditions resulted in the improved performance of lithium-ion batteries, extending their potential in various applications. Particularly, lithium-ion batteries with average electric power of 16 W and 17 W during charging were designed and simulated in the range of 0-12000 s using COMSOL Multiphysics software. This study efficiently employs the Taguchi optimization technique to develop lithium-ion batteries capable of storing a predetermined average electric power during the charging phase. Therefore, this method enables the battery to achieve complete charging within a specific timeframe tailored to a specificapplication. The implementation of this method can save costs, time, and materials compared with other alternative methods, such as the trial-and-error approach.

Modeling interaction between CO_(2),brine and chalk reservoir rock including temperature effect on petrophysical properties

Carbon dioxide(CO_(2))capture and sequestration through CO_(2)enhanced oil recovery(EOR)in oil reservoirs is one of the approaches considered to reduce CO_(2)emission into the atmosphere.The injection of CO_(2)into a subsurface geological formation may lead to chemical reactions that may affect the formation pore structure and characteristics.In this study,the effect of CO_(2)ebrineerock interaction on the rock petrophysical properties and mineral volume fraction was numerically investigated during CO_(2)injection into a chalk reservoir rock.A 3D numerical modeling and simulation were conducted using COMSOL®Multiphysics commercial software of computational fluid dynamics(CFD)to simulate CO_(2)ebrine core flooding process in a chalk core.The model was validated against a coreescale experimental data from literature.Simulation differential pressure data matched the literature experimental data closely and consistently indicating good agreement between them.Temperature effect on the performance of CO_(2)ebrineechalk sequestration was also evaluated in the present study.Results indicated that porosity was only slightly affected by temperature increase during CO_(2)injection in contrast to permeability that was substantially affected by temperature.Moreover,chemical reactions enhanced as temperature increased leading to significant increase in permeability.Thus,carbonated brine sequestration excelled at elevated temperature due to increased acidity which governs the sequestration process.The developed model maybe considered as a reliable tool to optimize various operating parameters of CO_(2)ebrine sequestration.