The function of battery management system ( BMS ) is slightly different from that of different companies. With the development of precision shunt technology and the improvement of market demand for battery management system, some functions are gradually added. Tesla's battery management system is one of the most successful BMS in the market at present. At present, many manufacturers are constantly making efforts to develop their own battery management systems, such as monitoring and collecting functions, collecting and calculating the overall parameters of battery packets, including total current, total voltage, maximum and minimum cell voltage, maximum minimum temperature point temperature and insulation.

 

 

In a complex battery management system, its main control functions include battery packet state estimation and management: State Of Charge, State of Health, SOF, State Of Power, State Of Function, and heat management etc. Let's analyze these master modules.
 
Firstly, the definition of SOH in battery management system is slightly different. The mainstream is an important parameter to characterize the aging degree of battery package according to the percentage of the total battery packet capacity to the initial capacity of the new battery. In fact, the power battery decommissioning index required by the national standard is defined according to the capacity characteristics.
 
Secondly, power battery in battery management system will be different with the decrease of SOC and the change of ambient temperature. If the residual power is too little, the temperature is too high or too low, the battery pack needs to reduce the power operation to protect the battery from irreversible damage and avoid the accident of heat runaway.
 

 

Thirdly, charge of battery management system accounts for the percentage of the current total available capacity, representing the current residual power, which may become the remaining mileage on the vehicle dashboard.
 
Fourthly, the SOF of battery management system is a relatively new concept, determined by SOC and SOH together. At present, more and more manufacturers join the electric vehicle production competition, the market becomes increasingly mature. Security and performance requirements will also increase. Several other useful state estimators should gradually become mandatory options for BMS algorithm design.