The full name of BMS is Battery Management System (Battery Management System), that is, manage the charge and discharge of the battery, so that the battery is in an optimal state, why do you need to manage it?
Because the battery cell is an electrochemical process, a number of cells constitute a battery, because of the characteristics of each cell, no matter how precise the manufacturing, with the use of time, environment, each cell will have errors and inconsistencies, so the battery management system is to evaluate the current state of the battery through limited parameters, a bit like a traditional Chinese medicine doctor, through the characterization, to see what disease you have. The physical and chemical analysis of the human body is like the electrochemical characteristics of a battery, which can be measured by large test instruments, but it is difficult for embedded systems to evaluate some electrochemical indicators, so BMS is an old Chinese medicine.