Most Lithium cell chemistries have a Nominal voltage lower than 4 Volts. So, in order to make it usable for higher voltage applications, we might have to use a boost converter or we can design a battery pack that provides the required output voltage by arranging the cells in a combination of series and parallel connections. Connecting cells in Seri. To make a battery pack, the first step is to know the nominal voltage of a cell. The cells selected by us have a nominal voltage of 3.7Volts while the charge voltage is 4.2V. So, in order to make a 12 V pack, we require 3 cells connected in series. The image of cells we used is shown below We are selecting a 3.7V battery with a capacity of 1200mAh.The best method is to use a spot welder. First, clean the surface of the cell and that of the nickel strip with a clean cloth to remove any dust or dirt particles from the surface. Place a nickel strip on the terminal of the battery and bring the prongs of the spot welder and make brief contact, you can repeat the process by rotating the battery to. Li-ion batteries require a battery protection module to keep the battery's health fine. These devices protect the battery pack from getting damaged by over-charge, deep discharge, and even from over-current. It is essential for keeping the battery safe and extending its life. To keep our battery safe, we have used an over-a-shelf 3-S 6Amps Battery. For testing the Module, after visually inspecting all the connections, check the voltage across P+ and P-. the voltage should be equal to the voltage across the B+ and B- pad. The next step is to test voltage across P- and B1, the voltage should lie be somewhere near 3.7V, since it is the voltage of a single cell. The next step is to test voltage a.