面向全过程的锂离子电池组均衡控制策略研究

发布时间：2019-05-10 10:31

【摘要】：锂离子电池单体电压低、容量小,为了满足电动汽车的性能需求,一般将大量单体电池串并联成组使用。伴随着电动汽车的研究与推广,单体不一致性问题越来越受到广泛的重视。由于单体不一致,成组后的电池在容量利用率、循环寿命方面远不及单体电池,均衡管理是解决不一致性问题有效途径之一,具有重要的实践意义,而目前均衡控制方法的研究处于初期阶段,均衡控制策略比较粗糙,存在很多难题亟待解决,论文针对均衡控制策略展开了较为深入的研究。首先介绍了锂离子电池的性能参数和其在不同条件下的充放电特性,对比分析了锂离子电池模型和荷电状态估算方法。接着论述了电池不一致性成因、影响及其解决途径,探索了依照不同均衡控制目标进行均衡控制的优缺点,对不同均衡能量转移方式下的电池组有效容量和荷电状态进行建模分析,研究不同均衡能量转移方式对电池组性能的影响。然后论文建立了单体电池放电过程的微观模型,基于该模型对电池组理想均衡状态的内涵和可达性进行探讨,然后确立了实际均衡目标,即在电池充放电末期控制端电压一致,而在其它时期结合工况和均衡能力预测电量变化,将单体剩余电量或者充满所需电量差异控制在均衡电路能处理的范围内,然后依据该目标设计面向全过程的均衡控制策略,并对该策略的性能进行分析。最后通过仿真和实验的方法对所设计的均衡策略进行检验,从电池组可放出电量以及平均均衡电量转移这两个指标对均衡策略进行评估,并与目前广泛应用的端电压中心均衡策略进行对比,仿真和实验的结果表明面向全过程的均衡控制策略能较为有效地减少均衡电量转移,提升电池组可放出电量。
[Abstract]:In order to meet the performance requirements of electric vehicles, a large number of single batteries are usually used in groups in order to meet the performance requirements of lithium ion batteries with low single voltage and small capacity. With the research and promotion of electric vehicles, more and more attention has been paid to the problem of monomer inconsistency. Due to the inconsistency of monomers, the capacity utilization rate and cycle life of the batteries in groups are far less than those of the single battery. Equilibrium management is one of the effective ways to solve the inconsistency problem, which is of great practical significance. At present, the research of equilibrium control method is in the initial stage, the equilibrium control strategy is relatively rough, there are many problems to be solved urgently. In this paper, the equilibrium control strategy has been deeply studied. Firstly, the performance parameters of lithium-ion battery and its charge-discharge characteristics under different conditions are introduced, and the lithium-ion battery model and charge state estimation method are compared and analyzed. Then the causes, effects and solutions of battery inconsistency are discussed, and the advantages and disadvantages of balanced control according to different equilibrium control objectives are explored. The effective capacity and charge state of the battery pack under different equilibrium energy transfer modes are modeled and analyzed, and the effects of different equilibrium energy transfer modes on the performance of the battery pack are studied. Then the microcosmic model of the discharge process of the single cell is established, and the connotation and reachability of the ideal equilibrium state of the battery pack are discussed based on the model, and then the actual equilibrium goal is established, that is, the voltage at the control end of the battery is consistent at the end of charge and discharge. In other periods, combined with the working condition and the equilibrium ability, the difference between the single residual electricity and the required electricity is controlled within the range that the equalizing circuit can handle, and then a balanced control strategy oriented to the whole process is designed according to the target. The performance of the strategy is analyzed. Finally, the designed equilibrium strategy is tested by simulation and experiment, and the equilibrium strategy is evaluated from the two indexes of battery pack discharge and average equilibrium electricity transfer. Compared with the widely used terminal voltage center balancing strategy, the simulation and experimental results show that the equilibrium control strategy for the whole process can effectively reduce the balanced power transfer and increase the battery pack to release electricity.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM912

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