| Plug-in hybrid vehicle have the same advantage of EV and traditional vehicle at fuel economy and low emissions. At the same time, PHEV also have the same performance to traditional cars, PHEV is one of the most important trend of new energy vehicle technology. Battery management system is one of the core component for PHEV, it’s very important for battery safety、battery life and vehicle performance. So it is worth for doing research on it.The main work of this project as followed:1. We studied the status of Power battery research, according to the special requirement of PHEV used battery, we choose NCM Lithium ion battery for this project.2. Considering the analysis of the function requirement and safety requirement and break down to battery system level, also define the ASIL level for battery system. Lastly, we analyze the characteristic of NCM Lithium ion battery.3. According to system function safety requirement, we design pre-charge function、High Voltage Interlock、vehicle crash safety management and insulation monitor to meet vehicle high voltage safety requirement. And finished BMS hardware top design and define the interface between software and hardware.4. The fourth chapter is the main content of this paper, first we design BMS software architecture, the software is divided into Platform software and Application software. According to NCM battery characteristic and test data, we choose ampere hour integration with OCV to estimate SOC. For SOH estimation we study the relationship of battery internal resistance、discharge current and battery voltage, SOH can indicate the heath of battery system. Combine with SOC and SOH, there have 3D Map, we can calculate the power of the battery system by look up table and linear interpolation. We fix the issue of battery status calculation.5. Lastly we test and calibrate BMS on the bench to validate the control strategy. Refer to test result, it can meet the requirement, and it is significantly. |
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