基于变参数结构的锂离子电池建模方法

Dynamically Parameterized Structure for Lithium-ion Battery Method

电动汽车及电网储能电站的快速发展对电池管理系统控制性能提出更高的要求,准确的电池模型及参数是保障电池管理系统中锂离子电池状态监测及高效能量管理的必要条件。传统等效电路模型受限于模型结构只能呈现单一时间尺度的阻抗特性,难以有效表征锂离子电池冲放电过程中内部复杂的物理、化学状态变化。基于锂电池充放电过程中的多时间尺度特征,提出一种采用变参数结构的一阶等效电路模型及相应的参数提取方法,该模型将时间因子引入容、阻网络,将容、阻参数可变范围从二维曲线扩展为三维曲面。所提出模型容阻参数能够在充放电及松弛周期内随电池状态的变化而改变,因此该变参数结构能够更为精准地描述电池内部电化学状态的变化。基于变参数特征建立了一阶变参数结构等效电路模型,并通过试验验证了模型的有效性。

The rapid development of the electric vehicle and energy storage station for power grid has put forward higher level requirements for the battery management system(BMS),accurate Lithium-ion(Li-ion)battery modeling and parameter identification are necessary for monitoring the states of the Li-ion battery and efficient energy management.Due to the model structure,the traditional equivalent circuit model(ECM)can only exhibit the impedance characteristics in one time scale.The complex dynamic physical and chemical status inside the Li-ion battery can not be effectively reflected in this condition.Thus,according to the multiple-time constant characteristic of the battery,It is proposed a dynamically parameterized structure for the first-order ECM and the corresponding parameter identification method.By introducing the time factor to the procedure of parameter extraction,the RC element in the model can be extended from two-dimensional curve to three-dimensional surface.In this way,the parameters of the model changed with the charging and discharging conditions during the relaxation period,and then the internal electrochemical state of the Li-ion battery can be exactly reflected.Based on the above foundation,this work establishes the dynamically parameterized structure for ECM,and the experimental validation has proved the effectiveness of the proposed method.