Experimental and Simulations Study of Thermal Performance of Cell-to-Pack Structure for a Li-ion Battery Pack

A new model for simulating battery temperature changes from the lower surface to the upper surface is proposed. The cell model is established with experimental calibration. Simultaneously, the Cell-to-Pack model is established through experimental benchmarking. In addition, the thermal properties of Cell-to-Pack and an ordinary battery pack that has an enclosure on the basis were compared under four different working conditions. The results indicate that adding an enclosure to the Cell-to-Pack has little effect on the thermal performance of the battery pack. Adding an enclosure to the Cell-to-Pack hardly improve the temperature uniformity of the battery under cooling conditions; the temperature difference between the upper and lower surfaces of the batteries at both ends of the module drops by approximately 0.5°C, while the central temperature difference is basically unchanged. Compared with fast charging without cooling, the battery temperature dropped by more than 12°C under the fast charge condition with cooling. More importantly, the specific energy and packaging efficiency of the battery dropped from 160.27Wh·kg−1 and 73.1% to 148.72 Wh·kg−1 and 67.8%, respectively, after the Cell-to-Pack was added with an enclosure.