Measurement and Estimation of Heat Generation Rate of Lithium-Ion Battery Considering SEI Growth and Lithium Plating

Thermal management system for battery is one of the most crucial components required to guarantee high efficiency and reliable operation of the battery. The system requires a battery model for accurate characterization of heat generated from the battery during operation. In addition, the sustainability of the model accuracy over the lifetime of the battery is another important factor. Since the battery heat generation is increased due to the increase of the resistance during cycling, the model needs to predict the change accurately. In this presentation, a thermal model incorporated into a reduced-order electrochemical model is introduced. The model considers detailed irreversible heat source terms by considering internal processes of the battery during cycling. In addition, since the battery parameters are changed when the battery is aged, a degradation model considering growth of solid-electrolyte-interphase (SEI) and lithium plating is also incorporated, and therefore, the battery parameters can be updated after degradation. In order to experimentally validate the model, the battery heat generation rate is measured at the beginning, middle, and end of life. The validation results show good agreement of the increase of the heat generation rate with degradation estimated by the model with that measured by the experiment. In addition, the effect of the degradation on heat source term is analyzed, and the main cause for the increase in the heat generation rate is revealed.