The Research And Design Of Battery Management System For Pure Electric Vehicles

With the rapid development of economy and technology, the life of humanbeings is becoming more and more rich and comfortable. But at the same time, problems such as environmental pollution and energy shortage are becoming increasingly serious, which even threaten the ecological safety of the earth. In the field of automobile, compared with the traditional cars, electric vehicles which have great advantages such as high energy efficiency, low noise, no pollution, etc. will gradually become the direction of future development.Battery management system, the core component of the electric vehicles, can not only improve the working life of batteries by the means of estimating and controlling the parameters such as voltage, temperature and current, but also reduce the cost of electric vehicles by making early prediction of the fault batteries.The research of the battery management system for pure electric vehicles was done in this thesis. Through the analysis of lithium-ion batteries, the overall architecture of this system was designed tentatively. Then the hardware and software ware designed based on this architecture. The balance and acquisition module, main controlling module and showing module ware included in the hardware. The software was designed based on ?C/OS-? real-time operating system. Finally, the hardware and software ware tested to verify its stability and reliability. The more detailed work was done as follows:(1) The overall design of battery management system:In this part, the research about the voltage characteristic, temperature characteristic, discharge capacity and the open circuit voltage characteristic of NCR18650PF type lithium ion battery was done. Based on this research, the function and the architecture of battery management system ware determined.(2) The hardware design of battery management system:In this part, the battery management system was divided into different modules, including the current, voltage acquisition module, main controlling module and showing module. Each module needs to complete the electrical design of schematic diagram, the selection of electronic components and the production of printed circuit board.(3) The software design of battery management system:In this part, the software was designed based on ?C/OS-? real-time operating system, including the transplant of the real-time kernel on the main control chip STM32F103VET6 and the development of application software such as initial startup task, battery voltage, temperature acquisition task, current collection task, charge and discharge control task, etc.(4) Systems debug and result analysis:In this part, with the help of corresponding equipment (lithium-ion battery pack, multimeter, etc.), the precision and reliability of obtained voltage, current and temperature, the timeliness of the LCD display ware tested.