Design Of Remote Monitoring For Lithium-ion Battery Management System In Electric Vehicles

Because of the increasingly shortage of the oil and other non-renewable resources, and environmental pollution problems, countries give great impetus to the development of new energy automobiles.New energy electric vehicles is the development direction of automobile industry.If want to make the rapid expansion in the electric car, we must improve battery safety and cruising ability and increase service life of the battery. At present, to enhance the character of service and lifetime of the battery, an effective method is to use battery management system(BMS) to manage power battery pack, but make use of BMS to manage battery pack still has much more room for progress. This paper has designed the remote monitoring for BMS on the basis of the original BMS. The main research work includes the following several aspects.(1) in order to real-time monitor the running state of the battery, increase data storage capacity and enhance computing power, improve the control strategy of the BMS, have completed the overall design of remote monitoring system. The system is consist of on-board data transmission union(GPRS DTU), GPRS network, Internet network and remote monitoring center software platform.By means of adding GPRS DTU and GPRS network in the BMS,the researchers can remote obtain battery running status data, and take advantage of remote monitoring center software platform saving the data and making secondary management. According to these large amounts of data, the BMS designer can design different control strategy based on different working condition of automobile and battery operation state.(2) for the sake of communicating with the electric vehicle BMS with CAN bus and communicating with remote monitoring center with TCP/IP network, have designed on-board data transmission union hardware circuit. The system use freescale chip as the main control chip, which is commonly used car chip. Peripheral hardware design mainly includes the voltage conversion module supplying power for system, the CAN communication module communicating with BMS, GPRS module communicating with the monitoring center.(3) based on the design of hardware circuit have programmed Software for on-board data transmission union. According to the hierarchical design the whole communication protocol is divided into the data link layer, data protocol layer, application layer. The paper has completed the communication function of CAN, CAN/GPRS communication protocol conversion and GPRS communication program.(4) the paper has realized the remote monitoring center software platform based on the Qt development environment. The monitoring center can communicate with on-board data transmission union, and real-time display state parameters of battery from BMS, and make use of Sqlite database to save the data. Through data playback, we can undertake secondary analysis of data,mainly using extended kalman filtering algorithm to verify SOC. Through experiment test, the various subsystems discussed in this article have achieved the expected function.