Thermal component for an electrochemical lithium-ion battery model: impact and variation on the battery performance

Abstract

Different battery chemistry gives different characteristics; however, these differences are gauged by the battery temperature through the Arrhenius law. A battery model is essential to predict and acts as a tool for analyzing the performance of a battery in the design stage, particularly for a battery pack design. The complexity of the battery model merely lies on the electrochemical part in which all of the diffusion, electron and charge transfer are modelled. On the other hand, the thermal component of the battery model is essential, allowing the temperature to have a direct impact on the battery performance. This paper compares and evaluates the impact of having different thermal component as a coupling to an electrochemical battery model. Concerning the electrochemical model, the thermal models are typically described based on the degree of its dimensionality. The highest degree of thermal model is a 3D-thermal model in which it maps the whole geometry of the battery. Nevertheless, we show that, having relatively higher degree of thermal model does not yield significant performance differences as compared to battery model that adopts a zero-dimensional thermal model. Adding a more complex thermal model only puts additional computational effort which extends the duration of the calculation. This suggests that the key integration of the thermal component to an electrochemical model is on the battery thermal-electrical interplay. The direction of the internal battery current during charge/discharge must be known or assumed before an appropriate thermal model is chosen. Increasing the dimensionality of the thermal model will be meaningless if the current density is not being feedback to the thermal model.