Study on Effect of Terminal Placement in Low Voltage Li-Ion 18650 Battery Pack

This paper investigates the impact of terminal placement on the performance of a Li-ion 18650 battery pack configured as 4P3S, connected via Nickel strips using spot welding technique. Fourteen patterns for the placement of the main positive and negative terminals are studied based on hypothetical assumptions. To study the effect of different charging currents, three rates are considered: 0.225C, 0.3C, and 0.375C. The analysis considers the individual battery cell voltage and current, the difference between each battery cell voltage and current, as well as the range of battery cell voltage. From the results, variations in the number of terminals and placement positions have significant effects on the voltage and current of each battery cell, potentially resulting in unequal charging currents for individual battery cells. Nevertheless, there are certain terminal placements, which cause less inequality in voltage and current distribution among the cells, and they can be applied without increasing the manufacturing cost of the battery pack. As a conclusion, this study provides valuable insights that can be used as a practical guideline for selecting appropriate terminal placements for Li-ion 18650 battery packs.