Simulation and comparative study of the effect of the electrical connection between the battery electrodes on the battery thermal behavior

Abstract

Accurately simulating and characterizing the thermal behavior of lithium batteries is vital for thermal design and management. Currently, the widely used simulation method for studying battery module thermal behavior and management is the virtual electrical connection. However, this method overlooks the presence of the busbar. Therefore, this study utilizes a physical electrical connection simulation method to investigate the impact of busbar heat generation and transfer on the thermoelectric behavior of the battery module. The results indicate that the busbar's heat production and transfer significantly affect the current density and temperature distribution, as well as the temperature uniformity of the battery module. The physical electrical connection simulation method accurately models the actual current transfer process between the battery electrodes, aligning with the real-world operation. In comparison to the virtual electrical connection simulation method, the physical electrical connection approach shows elevated local temperatures at the battery electrodes and the upper area in proximity to the busbar. It also exhibits more significant temperature gradients and worse temperature uniformity. Under real-world driving conditions, the temperature and heat generation of the battery undergo more frequent and wider fluctuations compared with constant-current discharge. The impact of the busbar's heat production and transfer on battery thermal behavior becomes more evident in these conditions. For example, under the FTP75, NEDC, and WLTC conditions, the maximum temperature increased by 8.04 °C, 28.43 °C, and 27.35 °C respectively, and the maximum temperature difference increased by 7.91 °C, 28.41 °C, and 27.19 °C respectively. Thus, the physical electrical connection simulation method significantly enhances the realism of battery module thermoelectric behavior simulations, contributing to the accuracy and effectiveness of thermal management analysis and product design.