锂离子电池的等效时变内阻模型及应用

Equivalent time-varying internal resistance model of lithium-ion batteries and the corresponding applications Equivalent time-varying internal resistance model of lithium-ion batteries with its applications

针对锂(离子)电池在恒流、恒压和/或恒功率等工况下,Thevenin等效电路模型无法在线辨识其模型参数,进而无法描述锂电池特性的问题,提出了一种新的等效时变内阻模型。分析表明,通过将锂电池的开路电压和内阻,描述成未知的时变电压和内阻,并利用安时积分和随机漫步模型,分别表示其未知时变电压和内阻的进化,就可为锂电池建立一种以状态空间进行描述的等效时变内阻模型。分析也表明,因电池充放电而产生的暂态极化电压,可由电池端电流与时变内阻的乘积,以及电池端电压观测噪声分布的组合进行描述。本文模型相比传统模型,在恒流恒压以及恒功率的工况下,SoC估计的均方根误差平均降低了48%。公开充放电测试数据集和实验的SoC估计,均验证了本文模型及分析结果的正确性和有效性。

In order to solve the problem that the traditional Thevenin equivalent circuit models’parameters of lithium-ion batteries cannot be identified under the constant current,constant voltage and/or constant power charge/discharge,a new equivalent timevarying internal resistance model is proposed.The analyses show that,when the open circuit voltage and internal resistance of a lithium-ion battery are characterized as an unknown time-varying voltage and internal resistance,respectively,the amp-hour integral and random walk model can be used to describe the evolutions of unknown time-varying voltage and internal resistance.Accordingly,an equivalent time-varying internal resistance model with a state space formula can be used to illustrate the characteristics of lithiumion battery.It is also shown that the transient polarization voltage produced by the battery charge and discharge can be explained by combining the product of end current at the battery and the time-varying internal resistance with the observed noise.Compared with the traditional model,the root-mean-square error of SoC estimation is reduced by 48% on average under constant current,voltage and power conditions.The correctness and effectiveness of our model and analytical results are verified by both the dataset based on the internet and experimental results.