Research and development of battery packs and their balancing methods for personal mobility vehicles: Summary of the doctoral thesis

The initial motivation for this Thesis is to design a battery pack for an ongoing electric kart for an educational project – a personal mobility vehicle in a broader sense. Hypothesis: The balancing performance of a battery management system can be improved by combining two different balancing methods into a two-layer balancing solution. Objectives: 1. To analyse the present electric vehicle battery systems. 2. To investigate lithium-ion battery technology and analyse the present battery balancing methods. 3. To perform investigative testing of lithium-ion cells. 4. To utilize the obtained knowledge to design a battery pack for a small electric vehicle. 5. To develop a custom two-layer balancing system. Means and methods of research MS Excel has been extensively used for calculations and data processing, especially for statistical analysis. Matlab was used for data processing, visualization, and measurement 6 process automation – instrumentation control scripts were designed and executed. HxD hex editor software was used to obtain raw data from memory cards, which were used for cell data logging. LTspice has been used for preliminary simulations of various parts of designed circuits. During the development, testing and experimental verification, a variety of laboratory equipment was used in different configurations. The list of used equipment includes various power supplies, oscilloscopes with assortment of probes, a thermal imaging camera, a battery impedance meter, electronic loads, precision power analyser and several multimeters. A few models of MSP430 family microcontrollers were used throughout this project. Both IAR Embedded Workbench (mostly in assembly language) and Code Composer Studio (mostly in C language) were used to program and debug microcontrollers. Orcad Capture, Layout and PCB editor was used for most PCB design. Occasionally, Altium designer was used as well. Experimental PCBs were manufactured in-house using PCB milling, while proven board manufacturing was outsourced.