Exchange current density at the positive electrode of lithium-ion batteries optimization using the Taguchi method

Over the past few years, lithium-ion batteries have gained widespread use owing to their remarkable characteristics of high-energy density, extended cycle life, and minimal self-discharge rate. Enhancing the exchange current density (ECD) remains a crucial challenge in achieving optimal performance of lithium-ion batteries, where it is significantly influenced the rate of electrochemical reactions at the electrodes of a battery. To enhance the ECD of lithium-ion batteries, the Taguchi method is employed in this study. The Taguchi method is a statistical approach that allows for the efficient and systematic evaluation of a large number of experimental factors. The proposed method involves varying six input factors such as positive and negative electrode thickness, separator thickness, current collector area, and the state of charge (SOC) of each electrode; five levels were assigned for each control factor to identify the optimal conditions and maximizing the ECD at the positive electrode. Also, main effect screener analysis and sensitivity analysis were conducted to confirm Taguchi analysis results. The results show that the Taguchi method is an effective approach for optimizing the exchange current density of lithium-ion batteries. This paper shows that the separator thickness followed by the positive electrode thickness play the major role in determining the lithium-ion batteries response. The main effect screener analysis and sensitivity analysis show the same effect of the chosen control factor which validate the Taguchi analysis results. By identifying the optimal conditions, it is possible to improve the performance of lithium-ion batteries and potentially extend their use in a variety of applications. As case study, lithium-ion batteries with ECD at positive electrode of 6 A/m2 is designed and simulated using COMSOL multiphasic within a frequency range of 10 mHz to 1 kHz. Electrochemical impedance spectroscopy (EIS) analysis using is carried out. As the frequency increased, the real part of the impedance of the simulated battery relative to the ground decreased because the charge transfer mechanism shifted from ionic to electronic conductivity. Additionally, the imaginary part of the impedance of the simulated battery relative to the ground decreased at higher frequencies due to a reduction in capacitive effects, with only minor inductive effects. This study opens the door widely in front of researchers and manufactures to design a lithium-ion batteries at specific exchange current density that suits specific applications in forward and direct way instead of trial and error approach.