Design And Application Of CAN Communication Module In Battery Management System

In recent years,the automobile industry has continued to develop.From the perspective of its development trend,new energy vehicles are still widely concerned.Its technology as an important support for the development of the industry has also been a research hotspot.One of the key technologies in the Vehicle is Battery Management System The function of the BMS is related to whether the power battery can provide sufficient kinetic energy for the car,which plays a key role in the development of electric vehicles.The data communication part is an indispensable link in the battery management system.The basis for data transmission from other controllers.Therefore,this paper firstly designs the CAN communication module in the battery management system to provide a communication interface for data transmission;secondly,in order to ensure the correctness of the node’s work,this paper focuses on the bus shutdown and unresponsive failures that occur in the network.The CAN network test and an online fault diagnosis and processing method are proposed,the purpose is to ensure the reliability and stability of data transmission on the bus;in order to modularize the signals sent by the battery management system and be intuitive Display and monitor various signals again.In this paper,a power battery monitoring platform is designed to achieve the purpose of real-time display and monitoring of the data on the bus.Finally,a real vehicle test verifies the reliability and stability of data transmission in the entire communication system.The main research contents are as follows:(1)Adopt an integrated layout scheme to build the overall framework of the communication module of the BMS and determine the network topology of the entire BMS.Then the data classification transmission method is used to divide the communication network of the BMS into two routes: one route is the vehicle CAN network,and the other route is the charging CAN network.Then on the basis of determining the network structure,the application layer protocol of the communication network in the BMS is formulated by the J1939 protocol specifications and design principles,and the structure and rules of data transmission are determined to provide a data source for communication on the CAN bus.Then,considering the cost and functional safety factors,the Infineon chip was used to design the software and hardware of the communication module in the battery management system,and the communication program of the BMS,the vehicle controller and the charger was completed.Finally,it provides a communication interface for data transmission.(2)According to the V-shaped process developed by the CAN network and the layered structure of the CAN bus,the main content of the CAN network test is summarized,the test tasks are clarified,and then the CAN bus test system is used to test the physical layer,data link layer and the application layer performs CAN network single-node testing to verify the reliability and stability of data transmission on the bus.Finally,compare the advantages and disadvantages of the offline diagnosis method and the online diagnosis method for the bus shutdown failure and node unresponsive failure in the CAN network,Propose an online fault diagnosis and recovery strategy to realize fault reporting and storage.(3)Adopt CAN bus to transmit data,design power battery monitoring platform.And based on the Lab VIEW environment,design the data acquisition system,.it’s purpose to realize the sending and receiving functions of CAN messages,and then the modular design method is used to design the upper computer interface of the monitoring platform,including the real-time monitoring module and the data Analysis and processing module,message display and storage and other core modules.It realizes the functions of signal sending,receiving,parsing,storing and displaying,and achieves the purpose of real-time displaying and monitoring data.(4)Carry out power-on and power-off experiments of electric logistics vehicles,charging experiments,and actual battery discharge vehicle tests,and import the messages collected by the CANTest software into CANoe for analysis.Then verify the closing timing of the relay and the change of SOC.The correctness of the protocol and the correctness of the hardware circuit and the underlying software code.In addition,the actual collected messages are compared with the messages displayed on the monitoring platform to verify the feasibility of the monitoring platform design.The final test results show that the entire data communication chain constructed in this paper is accurate and reliable.