As an electronic component of real-time monitoring, automatic balancing, and intelligent charging and discharging, the battery management system plays an important role in ensuring safety, prolonging life, estimating the remaining power, etc., and is an indispensable component in the power and energy storage battery pack. The energy storage battery management system is very similar to the power battery management system. The power battery system is in a high-speed moving electric vehicle, and there are higher requirements for the power response speed and power characteristics of the battery, the accuracy of SOC estimation, and the number of state parameter calculations. The scale of the energy storage system is very large, and the centralized battery management system is significantly different from the energy storage battery management system.
1. The position of the battery and its management system in their respective systems is different.
In the energy storage system, the energy storage battery only interacts with the energy storage converter at high voltage, and the converter takes power from the AC grid to charge the battery pack; Or the battery pack supplies power to the converter, and the electrical energy is converted into AC and sent to the AC grid through the converter. The communication of the energy storage system and the battery management system mainly have an information interaction relationship with the converter and the energy storage power station dispatching system. On the one hand, the battery management system sends important status information to the converter to determine the high-voltage power interaction. On the other hand, the battery management system sends the most comprehensive monitoring information to the PCS, the dispatching system of the energy storage power station.
2. The hardware logic structure is different
The hardware of the energy storage management system generally adopts a two-layer or three-layer mode, and the larger scale tends to be a three-layer management system.
The power battery management system has only one layer of centralized or two distributed, and there will be no three-layer situation.
From the functional point of view, the first 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 additional layer on top of this to cope with the huge scale of energy storage batteries.
3. There is a difference in communication protocol: The energy storage battery management system and the internal communication basically use the CAN protocol, but its communication with the external mainly refers to the energy storage power station dispatching system PCS, which often adopts the Internet protocol format TCP/IP protocol. The power battery is located in the general environment of electric vehicles using the CAN protocol, but according to the internal components of the battery pack using internal CAN, and the battery pack and the vehicle using vehicle CAN to distinguish.
4. The types of battery cells used in energy storage power stations are different, and the management system parameters are quite different. The current mainstream battery types for electric vehicles are lithium iron phosphate batteries and ternary lithium batteries. The external characteristics of different battery types vary greatly, and battery models cannot be used universally. The battery management system and the cell parameters must be one-to-one correspondence. The detailed parameter settings of the same type of battery cell produced by different manufacturers will not be the same.
5. The passive equilibrium conditions for the application of energy storage battery management system are relatively good, and the requirements of energy storage power stations for the balancing ability of the management system are very urgent. The scale of the energy storage battery module is relatively large, and the large single battery voltage difference will cause the capacity of the whole box to decrease, and the more batteries in series, the more capacity it will lose. From the perspective of economic efficiency, energy storage power stations need to be fully balanced. And because of the abundant space and good heat dissipation conditions, passive balancing can play a better role, using a relatively large equalization current, and there is no need to worry about the problem of excessive temperature rise. Low-cost passive equilibrium can be used in energy storage power stations.
