State of health assessment of Li-ion batteries using a multiple linear regression model

In this study, we investigate the impact of peak area in the incremental capacity curve, current, temperature, and charge capacity on battery performance through a regression model. We employ data from the University of Michigan Battery Lab to characterise the degradation of lithium-ion pouch cells under different cycling conditions. We propose two linear regression models, with and without interaction terms, to describe the relationships between the battery capacity and three independent variables: the test current, the temperature of the battery, and the area under the main peak of the IC curve. The results show that the inclusion of interaction terms in the model significantly improves the accuracy of the model, especially under varying thermal and current conditions.