The Research On Battery Management Technology Of Electric Vehicle Based On CAN Bus

CAN industrial local area networks, called controller area network, which is a serial bus with high speed , high reliability , and low cost for distributed real time control applications are widely used in the framework of real-time distributed industrial applications and distributed processing systems. An application method of battery management for electric vehicle based on CAN bus is introduced in this paper, which is universal,programmable and intelligent.The paper firstly gave a brief introduction the concept of EV, the current state of BMS, as well as the basic conception of CAN bus. There are three parameters to be measured, after comparing many methods and according to the available components, the measurement method and specific sensor is presented. In this paper, a relatively common method is chosen by the state of the application object, the bus node is consist of MCU,SJA1000 and PCA82C250. To measure voltage parameter, the method of relay and ADC is selected, and digital thermometer based of single wire bus is selected to measurement temperature. The hardware of the CAN bus and measurement circuit is designed based on these sensors and components, and the software is programmed, as well as the flow chart is given. To display all parameters, PC software based on USBCAN is designed with Visual C++ for monitoring all parameters of the CAN bus nodes.The newly developed BMS can safely separate the measuring (low voltage) from the operating circuit (high voltage) of battery. It can not only can predict the EV' s driving range, but also can effectively monitor the state of battery. It will give alarming signals when abnormal occurs and remind the driver to replace the deteriorated battery. Each Electric Control Unit (ECU) of BMS uses high precision sensor to collect data. Additionally, a microcontroller with CAN port was taken as the CPU in the new battery management system. The ECU served as an intelligent data collecting node. Each node was connected with a CAN bus to share the data with each other. This kind of linkage is not only useful for reducing the wiring harness, but also can provide flexible layout of batteries and furthermore improvement security and reliability.The study in this paper will improve the performance of electric vehicles and security of the batteries. It is also a good reference for future research in this area.