电动汽车锂离子电池建模及SOC估计方法分析-控制科学与工程专业论文.docxVIP

哈尔滨工业大学工学硕士学位论文 哈尔滨工业大学工学硕士学位论文 II II Abstract To cope with the increasing greenhouse effect and oil crisis, many countries focus on the research of electric vehicle (EV) for its zero emission. In the auto- motive field, electrochemical batteries are the core of energy source. Among var- ious kinds of batteries, Lithium-ion battery is an ideal type of battery due to its high energy ratio and high power ratio. State of Charge (SOC) of batteries is vital to the performance of EV, and SOC estimation is one of the key techniques of the batteries management system (BMS). This paper focuses on the battery model and method of SOC estimation for lithium-ion battery. Firstly, based on the electrochemical impedance spectroscopy (EIS) theory, an impedance-based model was built using the results of lithium-ion battery EIS test. To the problem raised in the impedance-based model, a high-order equiva- lent circuit model (ECM) was introduced. This paper used EIS technique to in- vestigate the influence of battery temperature on the battery. The consequences can amend the phenomenon that parameters of current model are constant, thus improve the adaptability to the battery temperature change. Secondly, according to the real-time estimation requirements for the EV, the method of state estimator was introduced. This paper verified observability of the model based on the method of nonlinear system observability. The result showed the battery model is observable, thus a state estimator exists. The overall design process includes poles placement and Lyapunov analysis. After pole placement is done, the LMI condition resulting from the Lyapunov analysis must be checked to verify the closed loop system is stable. According to the known model parame- ters, a real state estimator was set up. III III Finally, lithium-ion battery pulse current discharge tests at various tempera- tures implemented using battery test system to verify state estimator method. Re- sults show that even if Li-ion bat