The battery management system (BMS) is a control system that protects the safety of the battery. It monitors the battery’s use status at all times, adjusts the abnormal use of the battery through necessary measures, and provides safety guarantees for the safe use of the battery switch cabinet and the vehicle. The important purpose of the BMS lithium-ion battery management system is to ensure the design performance of the battery system, and to supply applications from three aspects: safety, durability, and power.

⒈In terms of safety, the BMS lithium-ion battery management system can protect the battery cells from damage and prevent safety accidents;

⒉In terms of durability, the BMS lithium-ion battery management system can make the battery work in a reliable and safe area and prolong the service life of the battery;

⒊In terms of power, the working condition of the lithium-ion battery is maintained to meet the requirements of the vehicle.

According to the requirements of the new national standard, the low-speed electric vehicle battery must be upgraded from the original lead-acid battery to the lithium-ion battery, and the BMS lithium-ion battery management system is a set of safety monitoring system customized based on the characteristics of the lithium-ion battery.

●Cell monitoring technology

1. Single battery voltage collection; 2. Single battery temperature collection; 3. Battery pack current detection;

Accurate temperature measurement is also very important for the working status of lithium-ion battery packs, including temperature measurement of individual cells and temperature monitoring of the heat dissipation liquid of the battery pack. It is necessary to reasonably set the position and number of temperature sensors to be used, and form a good cooperation with the BMS control module.

●SOC technology: Simply put, how much power is left in the battery

SOC is the most important parameter in BMS. Because everything else is based on SOC, its accuracy and robustness (also called error correction capability) are extremely important. If there is no accurate SOC, no amount of protection functions can make the BMS work normally, because the battery will often be in a protected state, and it will not be able to extend the life of the lithium-ion battery.

●Equalization technology

Passive balancing generally uses resistance to release the excess power of high-capacity batteries, so as to achieve the purpose of balancing. The circuit is simple and reliable, and the cost is low, but the battery efficiency is also low.