American lithium battery active balancing system -Lithium - Ion Battery Equipment
In the previous active battery balance system, to maintain the balance between modules, all small batteries in each module were connected with one of the small batteries in the adjacent module, so as to establish a path to transfer charge between them. Because the charge must be transferred to a small battery first, and then distributed to other small batteries; However, if the charge is transmitted to the module farther away, it will be transmitted for several times separately, which greatly reduces the efficiency of internal operation and makes more current consumed in the form of heat. The active balance battery management system of National Semiconductor provides a comprehensive system solution for large lithium-ion batteries in order to solve the old problems. This is a printed circuit board, equipped with multiple special application integrated circuits, which can provide three functions: active battery balance, high-precision data acquisition, battery protection and management.(Lithium - Ion Battery Equipment)
1. Active battery balance: The system adopts isolated inductance topology structure, which can supply high current and high efficiency battery balance function. The charge is transmitted in two directions between any small battery in the module and different modules, and the small battery and module can be balanced at the same time. At the same time, each battery module manages 14 small batteries, and the battery management system (circuit board) of each module can be stacked together to manage the high-voltage lithium ion battery pack. The balance current depends on the components (engineers can choose different targeted components between performance and cost).
2. Data acquisition: The battery management system is responsible for comprehensively monitoring the operation of the battery pack to ensure that the system measures the voltage of each small battery with high accuracy. In addition to balancing the charge, the analog front-end circuit responsible for this work can also ensure that the estimated value of the battery pack's charge amount and health status is accurate.
3. Battery protection and management: The system is equipped with multi-layer diagnosis and fault detection circuits. If undervoltage, overvoltage, battery overheating and other faults are found, small batteries or modules will actively send signals to the main controller. Relevant parameters will be compared with the programmable threshold stored in the firmware, and then the protection function will be realized through the switch program. The circuit board controlling each module is equipped with a multi contact insulated bus interface, which allows the circuit board to adjust communication with other modules and the main controller. At the same time, the bus is used to perform diagnosis, programming and configuration management functions.
This battery management system can be said to be quite advanced. The internal balance of power lithium-ion battery pack under charging, discharging and idle state can react quickly, accurately control the charging, storage and discharging power of small batteries, improve the safety, and also help to extend the service life. This system is expected to be used for the management of large lithium-ion batteries used in power station energy storage facilities.