In response to the problems of poor interpretability and strong dependence on data for battery state of health(SOH) estimation of lithium-ion batteries based on machine learning
this paper proposes a SOH estimation method for lithium batteries with interpretability. First of all
this work analyzes that as batteries age
the distance between the charging voltage and the first charging voltage exhibits a good trend
and proposes a distance metric based on the concept of Shapelets that can capture the degradation trend of the battery
and further determines the range of the Shapelets candidate set through correlation analysis to improve the efficiency of the feature extraction. The selection of Shapelets is carried out in combination with the BP model optimized by the subtraction-average-based optimizer (SABO) algorithm. Finally
the Shapelets-based SABO-BP model is designed to realize the effective estimation of battery SOH. The proposed method is validated on the Stanford-MIT dataset
and batteries with different charging strategies are selected for test
the MAE of the battery SOH estimation are all maintained within 0.5%
and can reach as low as 0.19%; the RMSE are also all maintained within 0.6%
and can reach as low as 0.26%; and the stays above 0.98 and reaches up to 0.995. The experimental results show that the proposed method is able to accurately predict the SOH of lithium batteries with limited data
which confirms the generalization and practical value of the proposed algorithm.
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