ABSTRACT
Balancing of battery cells in electrical components such as electronic equipment and electric vehicles is very important for the extension of battery run time. The way to extend useful life of the battery is by equalizing the balance of cell voltage and SOC when they are in complete charge. In order to control and extend the life of the battery, the project is aimed at developing a cell balancing unit that is arranged in a way that it equalizes the voltages in each cell so they can all function at the same capacity and prevent degradation of a single cell and the whole battery pack at large.
The cell balancing unit was constructed for series connected batteries using the passive method and it consists of various important parts like the micro-controller, capacitors, resistors, transistors, voltage regulator, diodes, LCD, etc. Various cell balancing systems were studied and discussed in terms of their specification, number of cells they can balance and their balancing current. The total hardware design comprises of the battery pack, balancing and protection unit, cell monitoring unit and power supply. The software development for the monitoring unit was done in Arduino IDE and software called Xgpro was used to burn the developed code into the micro-controller to enable it read the cell voltages of each cell.
At the completion and implementation of the cell balancing unit, it was shown that the balancing unit is able to maintain the SOC of the individual batteries and also make sure that charges in all the cells are equal after the full charge and thus the cells are balanced. Experimental results are provided to verify the topology of the balancing unit alongside its effectiveness and efficiency in balancing the battery pack.
