基于数据驱动的电池系统泛化SOH估计方法

准确可靠的电池健康状态估计是保证锂离子电池安全运行的关键，同时为失效预警提供参考。提出一种适用于电池单体和电池组的健康状态估计通用方法。首先，提出基于局部充放电数据的电池单体高效健康因子提取方法，保证健康因子和容量的高相关性和实现健康因子的在线可获取性。其次，提出考虑电池组容量衰减和不一致性的特征生成策略，利用主成分分析获取融合特征，利用双时间尺度滤波和电池组等效电路模型拓宽特征提取方法的应用范围。然后，基于高斯过程回归算法框架，考虑健康因子和容量衰减的整体关系和局部变化提出改进的高斯核函数提高估计精度和可靠性。最后，利用多个试验数据集验证算法在不同应用条件下的泛化能力。估计结果表明，对恒流放电工况的电池单体估计误差小于1.28%，在动态变温条件下电池单体估计误差小于1.82%；串联电池组的验证结果表明在各种应用场景下估计误差均小于1.43%。提高了电池系统健康状态估计的精度以及在广泛应用场景下的适应性。

Generalized Data-driven SOH Estimation Method for Battery Systems

Accurate and reliable battery state of health estimation is the key to ensuring the safe operation of lithium-ion batteries, and provides a reference for failure warning. A general method to estimate the state of health of both battery cells and battery packs is proposed. Firstly, a method for extracting high-quality health indicators of battery cells based on partial charge or discharge data is proposed to ensure the high correlation between health indicators and battery capacity and the online availability of the health indicators. Secondly, a feature generation strategy that considers the capacity attenuation and inconsistency of the battery pack is proposed. The final fusion feature is extracted by using principal component analysis to reduce the dimensionality of the feature matrix. The dual time scale filtering and battery pack equivalent circuit model are combined to broaden the extraction under dynamic discharge conditions. Then, based on the framework of the Gaussian process regression, an improved Gaussian kernel function is proposed considering the overall relationship and local changes of the health indicators and capacity attenuation. Finally, multiple experimental data sets are used to verify the generalization ability of the proposed method under different application conditions. The estimation results show that the proposed method has an estimation error of less than 1.28% for battery cells under constant current discharge conditions, and an estimation error of less than 1.82% for battery cells under dynamic working conditions with changeable environmental temperatures. The verification results for series battery packs show that it can be used in various application scenarios with estimation errors all less than 1.43%. The accuracy of and adaptability in a wide range of application scenarios of battery state of health estimation for battery systems are improved.