In a pure electric vehicle, the power battery pack is one of the core components, which occupies a very high proportion of the vehicle manufacturing cost, and its performance directly affects the driving performance and safety of the vehicle. The power batteries used in early pure electric vehicles were mostly lead-acid batteries. Due to their low energy density, short cruising range, and short service life, this type of battery was gradually replaced by products such as lithium-ion batteries with outstanding advantages.

　　The currently vigorously developed new energy vehicles are mainly divided into three categories: these three types of electric vehicles have their own different structures and working principles, forming their own different characteristics, and they are also at different stages of development. Pure electric vehicles use on-board power battery packs (such as lithium-ion batteries, lead-acid batteries, nickel-metal hydride batteries and nickel-cadmium batteries, etc.) as their only energy source, and are equipped with high-power motors to drive the car. Therefore, unlike traditional internal combustion engine vehicles The biggest difference is the unique electric drive and control system of pure electric vehicles. Compared with hybrid electric vehicles, pure electric vehicles have low noise, no pollution, zero emissions, and a simpler chassis structure. Compared with fuel cell vehicles, all aspects of technology are relatively more mature, and they have higher reliability and safety. Therefore, pure electric vehicles have been highly valued by governments and car companies around the world, and many companies have achieved mass production and started demonstration operations in certain areas.

　　In a pure electric vehicle, the power battery pack is one of the core components, which occupies a very high proportion of the vehicle manufacturing cost, and its performance directly affects the driving performance and safety of the vehicle. The power batteries used in early pure electric vehicles were mostly lead-acid batteries. Due to their low energy density, short cruising range, and short service life, this type of battery was gradually replaced by products such as lithium-ion batteries with outstanding advantages. Lithium-ion batteries have attracted the attention and use of many electric vehicle manufacturers at home and abroad due to their high charge and discharge efficiency, high energy density, and strong endurance.

　　Although lithium batteries have more advantages than other types of batteries, they are also limited by factors such as cell materials and current manufacturing processes, resulting in differences in internal resistance, capacity, and voltage between single-cell lithium batteries. In practical applications, the individual cells in the battery pack are prone to uneven heat dissipation or excessive charging and discharging. Over time, these batteries in poor working conditions are likely to be damaged in advance, and the overall life of the battery pack is greatly shortened. Not only that, there is a danger of explosion when the battery is in a severely overcharged state, which causes damage to the battery pack and also threatens the safety of the user's life. Therefore, it is necessary to equip the power battery pack on the electric vehicle with a set of targeted battery management system (Battery Management System, BMS), so as to effectively monitor, protect, energy balance and fault alarm of the battery pack, thereby improving the entire power battery pack Work efficiency and service life.

　　As the monitoring and management center of the battery pack of pure electric vehicles, the battery management system must monitor the temperature, voltage, charge and discharge current and other related parameters of the battery pack in real time and dynamically. The battery pack presents dangers such as overcharging, overdischarging, overheating, and short circuit. In addition, the system must accurately estimate the battery's SOC during the entire life cycle of the battery pack, and timely feed back key information such as remaining power, driving range, and abnormal faults to the driver in a suitable manner. Complete the data exchange function between the system and the vehicle ECU or host computer in a suitable way.

　　However, these are the functions and performances of BMS that can be achieved under the best design and ideal conditions. At present, from various electric vehicle accidents related to power batteries or the overall performance of related BMS products actually applied to automobiles It can be seen from the performance that the functions of the currently widely used battery management system are not perfect, the technology is not mature enough, the scope of use is limited, and the versatility is not strong. It can be summarized in the following five aspects:

　　①The accuracy of the battery management system's collection of related parameters of the power battery pack is not accurate enough under long-term use.

　　②The battery management system has not yet fully realized the accurate estimation of the SOC value of the power battery pack during the entire life cycle.

　　③The control effect of the energy balance among the individual cells in the battery pack needs to be further improved.

　　④Battery management system has insufficient self-diagnosis and self-maintenance functions for itself and battery packs.

　　⑤The battery management system products currently appearing are generally targeted, with limited scope of use, and their portability and versatility are not strong enough.