Simply put, the BMS battery management system is the housekeeper of the battery, which plays important functions such as ensuring safety, prolonging the service life, and estimating the remaining power. , to reduce the loss caused by battery damage.
The energy storage battery management system is very similar to the power battery management system. Most people don't know the difference between power battery BMS management system and energy storage battery BMS management system. Next, briefly introduce the difference between the power battery BMS management system and the energy storage battery BMS management system.
1. The positions of batteries and their management systems in their respective systems are different
In the energy storage system, the energy storage battery only interacts with the high-voltage energy storage converter. The converter takes power from the AC grid to charge the battery pack, or the battery pack supplies power to the converter, and the electric energy is converted to AC through the converter. power grid.
The communication and battery management system of the energy storage system mainly have an information interaction relationship with the converter and the dispatching system of the energy storage power station. On the other hand, the battery management system sends important status information to the converter to determine the high-voltage power interaction status. On the other hand, the battery management system sends the most comprehensive monitoring information to the dispatching system PCS of the energy storage power station.
Electric vehicle BMS communicates with the electric motor and charger in the energy exchange relationship under high voltage, has information interaction with the charger during the charging process, and has the most detailed information interaction with the vehicle controller in all application processes.
2. The logical structure of the hardware is different
For energy storage management systems, the hardware generally adopts a two-tier or three-tier model, and the larger scale tends to be a three-tier management system. The power battery management system has only one layer of centralized or two layers of distributed, almost no three layers. Small cars mainly use centralized battery management systems. Two-layer distributed power battery management system.
From a functional point of view, the first-layer and second-layer modules of the energy storage battery management system are basically equivalent to the first-layer acquisition module and the second-layer main control module of the power battery. The third layer of the energy storage battery management system is an added layer on this basis to deal with the huge scale of the energy storage battery. Mapped to the energy storage battery management system, the management capability is the computing power of the chip and the complexity of the software program.
3. The communication protocol is different
The energy storage battery management system and internal communication basically adopt the CAN protocol, but the communication with the outside mainly refers to the PCS of the energy storage power station dispatching system, and the Internet protocol form TCP/IP protocol is mostly used.
The general environment of power batteries and electric vehicles adopts the CAN protocol, but the internal CAN is used between the internal components of the battery pack, and the whole vehicle CAN is used to distinguish between the battery pack and the whole vehicle.
4. The core types used in energy storage power stations are different, and the management system parameters are quite different
Considering the safety and economy of energy storage power stations, when choosing lithium batteries, lithium iron phosphate is more preferred, and more energy storage power stations use lead batteries and lead-carbon batteries. The current mainstream battery types for electric vehicles are lithium iron phosphate batteries and ternary lithium batteries.
Different battery types have great differences in their external characteristics, and the battery model is not universal at all. There must be a one-to-one correspondence between the battery management system and the core parameters. The same type of cores produced by different manufacturers have different detailed parameter settings.
5. Threshold setting trends are different
Energy storage power stations have more space and can accommodate more batteries, but some power stations are located in remote locations and are inconvenient to transport, making it difficult to replace batteries on a large scale. The expectation of the energy storage power station for the battery cell is to have a long life and not to fail. On this basis, the upper limit of its operating current is set relatively low to prevent the electrical load from working. The energy characteristics and power characteristics of the battery cell do not have to be particularly high. Mainly depends on cost performance.
The power battery is different. In the limited space of the vehicle, the battery that has been installed with great difficulty hopes to maximize its capabilities. Therefore, the system parameters refer to the limit parameters of the battery, and this application condition is not good for the battery.
6. The state parameters required to be calculated by the two are different
SOC is a state parameter that needs to be calculated by both. However, as of today, there is no uniform requirement for energy storage systems. What kind of state parameter calculation capabilities does an energy storage battery management system need? In addition, the application environment of energy storage batteries has a relatively rich space and a stable environment, and small deviations are difficult to perceive in large systems. Therefore, the computing power requirements of the energy storage battery management system are relatively lower than those of the power battery management system, and the corresponding single-string battery management cost is not as high as that of the power battery.
7. The passive balance conditions for the application of the energy storage battery management system are good
Energy storage power stations have very urgent requirements for the balance capability of the management system. The scale of the energy storage battery module is relatively large, and multiple strings of batteries are connected in series. The large monomer voltage difference will reduce the capacity of the entire box. The more batteries connected in series, the more capacity will be lost. From the perspective of economic efficiency, energy storage power plants need to be fully balanced.
In addition, passive balancing can work better when there is plenty of space and good heat dissipation conditions, so a larger balancing current is used without worrying about excessive temperature rise. Low-cost passive balance can flex its muscles in energy storage power stations.