Modular Battery Management System Concept for Medium-High Voltage System

Abstract

The development of lithium batteries as an energy storage system is getting higher equal to the development of eco-friendly energy needs. However, lithium batteries have disadvantages in electrical and temperature interference. Series and parallel configuration causes voltage imbalance and leads to degradation performance of the battery. The focus of the research is the development of BMS with voltage monitoring and balancing features for the 12-series battery pack configuration. Monitoring can be done by observing electrical parameters, are cell voltage and battery temperature. The results of the simulation and modeling of BMS and Lithium-ion Battery show that the flat-zone voltage on the LFP UNS battery is in the 10-90% SoC range (generally SoC 20-80%), and the characteristics of lithium battery are current affects the battery voltage curve (high current causes a high voltage drop), while temperature affects the internal resistance (low temperature causes an increase in internal resistance). The BMS hardware monitoring test shows the accuracy and precision of the voltage sensor at 99.7064% and 99.9998%, while the temperature sensor performs the accuracy and precision of 95.4909% and 100%, respectively. The passive balancing method with Switched Shunt Resistor shows a nominal balancing current of about 170mA with a 20mV voltage drop.