| Car-carried power battery system, as the power carrier and power source, is an important part of electoric car and hybrid car. Lithium-ion batteries, with the advantages of high energy-quality ratios, long life cycle, high charge and discharge rate, safety, and non-pollutions, have been widely applied in the electronic car industry. Since car-carried power system are generally made by parallel connection of serveral single battery, battery management system(BMS) is essentially imporant componet to facilitate battery packs’ safe and reliable working, because BMS can effectively monitor the major variables, evalutate the state of charge, avoid the safety risk from over-charging and-discharging.Currently BMS remains to be the customized products, with some inherent disadvantages such as high integreation, inflexibility, and poor maintainability. BMS mainly consists of serveal functions: cell voltage, module temperature acquisition; balanced management control; battery system voltage, current, insulation detection; estimate the state of charge; fault diagnosis and after treatment.This study aims to investigate the functions and demands of car-carried BMS. According to the system requirements, the BMS is designed as a distributed modular structure, consisting of the battery management unit(BMU), the cell measuring balance(CMB), current and voltage acquisition system(CVS). Specifically, CVS applied the thecnology-mature module which is integrated into the system through VAN to enable data interaction. The thesis proceeds as follows:(1) the hardware design of BMU.(2) according to the car-carried software framework standards, this study overall software architecture of BMU, including FlashBoot Loader boot program automatical generation, CAN communication, CCP calibration protocol, UDS unified diagnostic services agreement, and basic Software(BSW) development.(3) the application layer software on the system charge and discharge management, SOC estimation, fault diagnosis and treatment functions.(4) completed the system cell voltage acquisition and balancecontrol funtion by using the Intelligent integration chip LTC6804, the battery management unit communicate with the sub system by the enhanced SPI communication interface, avoid the work of software development by in CAN communication.Based on the measuremnts and tests on BMS key parameters, system state of charge, balance control, mulfuntion check and processing etc.,this research outcomes lead to the the enhanced performance of the battery system in terms of security, reliability, functuon and working life, which valides the practical value of this study. |
