With the increasing popularity of new energy vehicles, the battery pack communication and control technology of new energy vehicles are becoming more and more mature, this paper introduces the composition of the battery management system of new energy vehicles and the functional structure with other modules, and briefly summarizes the basic principles of AC charging system control logic, and further elaborates the importance of battery pack communication and control technology.
First, the battery pack overview
For the new energy vehicle battery pack, the battery pack for the overall operation of the electric vehicle performance and safety is of great significance, and the battery pack is also an important power basis in the operation of the electric vehicle, from the current industry for the overall design of the battery system, the battery pack is mainly divided into two types, one type is the structure of the integrated battery box.
For this structure of the battery pack, it can be tailored according to the new energy tram's own structure and design the two into a whole, forming an integrated mode, so as to better realize the optimal design configuration of the battery pack and the overall structure of the tram, and at the same time, the monitoring performance of the battery and the management interface of the battery can be set in the entire tram operation space.
The other kind of battery pack is a good compatible structure with the whole vehicle presented, this kind of battery pack first does not consider too much about its placement in the tram space, but directly to some structural components of the new energy electric vehicle directly converted into a battery, these two battery packs are generally popular and used in the current market.
Second, the application of battery management system in electric vehicles
1. Brief description of battery management system
For new energy electric vehicles, its main components are power batteries, motor controllers, motors and necessary power transmission systems, compared with traditional fuel vehicles, it is not through the combustion of fossil energy to drive the internal combustion engine to promote the operation of the car, new energy electric vehicles mainly use power batteries as their source of energy.
2. Battery management main module
Generally speaking, BMS is a core hub of connection between the three parts of the vehicle power unit, battery pack and charging unit, on-board charger and control center, and the main function of BMS is reflected in the information monitoring and communication functions of the entire battery pack, which can be divided into the following main aspects:
2.1 Battery information collection module
The collection of battery information is mainly collected through sensors in the collection of the working voltage in the battery pack and some current and ambient temperature in the charging and discharging process, and finally transmitted to the main control chip through the bus to complete the control.
2.2 Electrical control management module
In the process of specific charging and discharging of new energy vehicles, the power battery pack may occur in a certain situation overcharge, overdischarge and unbalanced power during charging, etc., and the generation of these problems will also have a greater impact on the working life and work efficiency of the battery, the above situation occurs from time to time in the process of new energy vehicle operation, and the battery management system can respond to this situation in time, such as quickly implementing the operation of charging and discharging circuit cutting and so on.
2.3 Battery safety protection module
For the battery management system, there is also a very important responsibility is to effectively monitor whether the battery is abnormal in the process of work, once the battery pack is found to be abnormal in the process of operation, it can ensure that the system makes certain countermeasures in time, so as to effectively ensure that the entire battery pack is in normal operation, and can also prevent the occurrence of dangerous accidents such as explosion.
2.4 Data communication display module
The battery management system can collect some battery information status data, first send this information to the BMS main control chip for estimation, and then the results of chip processing can be sent to other modules through the CAN bus for sharing and use, in this way, the battery management system can effectively display some serial port information on the host computer in real time.
Such a display module can make the driver and maintenance staff a clear control and effective judgment of the relevant information of the entire new energy vehicle vehicle, which has good use significance for the later vehicle maintenance and maintenance and the collection of status data.
Third, charging control logic application
In the process of AC charging of new energy vehicles, the first charging gun is connected to the charging port on the car, and this process to ensure that the high-voltage power-on function is in a normal state, and the on-board charging module on the car will automatically effectively identify the voltage connected to the AC charging port.
The car charging module will recognize a specific resistance value between the CC terminal of the charging gun and the CP terminal, and the charging gun will also be connected correctly by default, and the relevant control module on the car will be in a wake state after this state is activated, and then the car charger will further receive a pull-low signal from the CP terminal on the charging gun.
After receiving this signal, the battery management system will send a charging connection signal, and send relevant instructions to each contactor and keep it closed, so as to effectively realize the preparation of the entire high-voltage system for precharging, after the pre-charge preparation is completed, the battery management system will disconnect the pre-charge contactor and further control the closure of the AC contactor, thereby completing the entire preparation process of AC charging.
IV. Conclusion
All in all, the battery management system will realize the monitoring of each module through the internal bus, and collect the operating parameters of each module, and after certain calculation and processing, the information will be transmitted to the vehicle charging module, vehicle controller and other control components through the external CAN bus, so as to achieve the good operation of the entire communication control system.
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