Analog protections for Electric Vehicle Batteries

In the last few years the issue concerning the pollution and the protection of the environment has predominantly entered into the daily lives of us all, and it is becoming the guiding compass for new investments. In the automotive field is happening one of the biggest change of its history, it is switching from the use of fossil fuels as unique source of energy for the vehicles, to the adoption of electrical energy as primary supply, in other words to replace the traditional combustion engine with the electric motor. An important phase of this turning point is the definition of an energy storage system that meets market demand from the point of view of the autonomy and safety requirements. Lithium-ion battery offers the most promising technology in terms of energy density, power density as well as cycle life, against, lithium ion batteries are very sensitive to usage outside of the specified operating range parameters, like the operating temperature, voltage thresholds and the maximum charge and discharge current. A Battery Management System is thus required to monitor all the sensitive parameters and to ensure the battery is operating safely and within the specified range. The primary purpose of the BMS concerns the safety and protection of the battery, to minimise the risk of sudden failure and to maximise the life of the battery. The objective of this thesis was to contribute to the development of the BMS for real implementation in the prototype battery pack being developed in the company with which I am collaborating, BeonD. My work focused on sizing and choosing components for a safe battery pack operation, starting with a low level protection which consists on the protection of the single cell, up to an higher level protection which is functionl for securing the entire pack. Future works are required in order to better test the system and evaluate any problems that have not yet emerged in my research work.