Investigations on methods to improve the lithium-ion battery performance at fast charge and discharge rates

• Main Author: Leong, Jun Yang
• Other Authors: Madhavi Srinivasan
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2021
• Subjects: Engineering::Materials
• Online Access: https://hdl.handle.net/10356/147780
• Institution: Nanyang Technological University

In this study, lithium-ion battery safety and performance will be studied and investigation of methods that could improve them. Project A Battery thermal management system (BTMS) has significant impact on the performance, lifetime and safety of battery. Cold plate indirect cooling method of BTMS was used in this study. The effect of having thermally conductive silicon between the surface of the cell and cold plate has been investigated. The cold plate with thermally conductive silicon shows better cooling performance compared to the one without. However, such high temperature is known to cause accelerated degradation, loss of lithium and poor cycle life. Consequently, deposition of lithium and other organic compounds and increase in resistance. The deposited lithium can grow into dendrite structures causing short-circuit, lead to thermal runaway. The optimization of ratio of cathode and anode mass ratio could be a potential strategy to minimize the effects. Hence, in Project B investigation of the effects of cathode and anode mass ratio on the battery performance had been done. Project B Fabrication of lithium-ion batteries has various considerations including the choice of negative (N, anode) and positive electrode (P, material). The capacity ratio of negative to positive electrodes (N/P ratio) is the most important factor to design the lithium-ion batteries with high performance. The effect of N/P ratio (1.10, 1.20, and 1.30) on cell performance at a fast charge rate has been investigated in this study. The cell with capacity ratio of 1.2 shows better cyclability compared to cells with capacity ratio of 1.1 and 1.3 which shows more capacity fade and less capacity retention as number of cycle increases. This study on the effects of capacity ratio on lithium cells can be of useful in designing full cell that can be fast charge without lithium plating.