Key Laboratory of Advanced Manufacturing Technology for Automobile Parts,Ministry of Education,Chongqing University of Technology,Chongqing 400054,China
Lithium-ion batteries are prone to capacity degradation during long-term operation, which significantly affects the driving range and safety of electric vehicles. To accurately estimate the battery’s state of health (SOH), this study proposes a hybrid SOH estimation method that integrates a Long Short-Term Memory (LSTM) network with an Informer architecture. The Local Outlier Factor (LOF) algorithm is employed to preprocess the charging data of experimental batteries, and the maximum tangent angle of the charging voltage curve, along with its corresponding time, is extracted as health features. The correlation between these health features and SOH is analyzed using the Spearman correlation coefficient. By combining the advantages of LSTM in capturing local temporal dependencies with the Informer’s ability to model global relationships, an LSTM–Informer serial network is constructed. The extracted health features are used as model inputs to achieve accurate SOH estimation. Experimental results demonstrate that the proposed method achieves high estimation accuracy, with the maximum absolute error maintained within 2.5%, and both the root mean square error (RMSE) and mean absolute error (MAE) within 1%. Compared with traditional single-network methods, the proposed method exhibits superior estimation performance and generalization capability.
锂离子电池凭借其高能量密度、长循环寿命、低自放电率以及无记忆效应等优势,广泛应用于电动汽车[1]。然而,在实际应用中,电池随充放电循环发生不可逆的化学反应和结构变化,导致容量衰减与性能退化。电池的退化速度受使用习惯和环境影响显著,在不规律充放电、急加速/急减速以及极端温度等情况下会加速退化。电池的健康状态(State of Health, SOH)影响其续航能力和安全性能,引发里程焦虑。因此,准确估计电池的SOH具有重要意义[2]。
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