一种基于恒流充电阶段电压数据的锂离子电池健康状态估计模型

An estimation model of the state of health of lithium-ion batteries based on the voltage data in the constant current charging stage

  • 摘要: 为解决储能系统电池管理中健康状态(State of Health, SOH)估计算法需兼顾高精度与轻量化的需求,本研究提出一种局部电压拟合(Local Voltage Fitting, LVF)方法。该方法将等效电路模型参数和待估计SOH值作为联合待定系数,构建电池恒流充电阶段电压与充电时间的映射关系模型,进而通过非线性拟合直接求解SOH估计值。基于18650型磷酸铁锂(LiFePO4)电池的循环寿命实验数据,对所提出模型的性能进行了验证。实验结果表明,该模型展现出了良好的SOH估计效果,最大相对误差(Maximum Relative Error, MRE)为0.009489,均方根误差(Root Mean Square Error, RMSE)为0.001249。与BP(Back Propagation, BP)神经网络和梯度提升回归树(Gradient Boosting Regression Tree, GBRT)算法进行对比分析发现:LVF模型的MRE相较于BP和GBRT算法分别降低了60.27%和56.80%,RMSE分别降低了83.04%和79.12%。此外,还利用了同济大学公开的电池实验数据对该模型进行验证,同样取得了良好的SOH估计效果,并且发现LVF的估计精度不受电池一致性的限制。本文所提出的LVF模型具有轻量可维护且SOH估计精度高的优点,适用于工程实际应用。

     

    Abstract: This paper addresses the application requirements for Lithium Iron Phosphate (LiFePO?) batteries State of Health (SOH) estimation algorithms in energy storage systems, which demand both high accuracy and model simplicity. A Local Voltage Fitting (LVF) model is proposed and validated. First, combining a second-order equivalent circuit model, the basic mathematical expression for SOH estimation is derived based on the relationship between terminal voltage and charging time during the constant-current charging phase of the battery; To enhance the model's applicability for fitting lithium iron phosphate batteries, this study selected segmented voltage data within the State of Charge (SOC) range 0.30, 0.90 from the constant-current charging curves of each cycle, excluding the difficult-to-fit regions at the ends of the curves, thereby establishing the local fitting framework for the LVF model.

     

/

返回文章
返回