Numerical investigation of the thermal management of liquid cooled lithium-ion battery pack in waved

In recent years, energy and environmental issues are starting to come to the fore more and more. Electric vehicles powered by lithium-ion batteries offer a great potential advantage in alleviating these problems. Compared with other batteries, lithium-ion batteries have advantages such as high specific energy, high energy density, long life, low self-discharge rate and long shelf life. Temperature control of lithium-ion batteries used as a power source in electric vehicles is very important in terms of battery performance. In the study, 22 lithium NCA 18650 type batteries were connected in parallel. A battery thermal management system was designed by placing the batteries in 4 rows in 6-5-6-5 groups. For this battery thermal management system, 3 different channel U, 2-U and 4-U twisted channel structures were modeled and the models were examined by changing the number of fluid divisions in the channels and the inlet directions of the refrigerant to the channels. The cooling effects of the battery were investigated for the 4-U twisted 4-split wavy channel created with the FloEFD program, which was considered for parametric studies. The temperature of the water used as the refrigerant and the ambient temperature is 25°C, and the working pressure is 1 atm. Numerical analyzes were performed with the FloEFD program at different C-ratios (1C-2C-3C) and different Reynolds numbers (800-1200-1600-2000). As a result of U, 2-U and 4-U twisted duct analysis, it was determined that the Tmax value of the model with 4-U twisted duct structure decreased by 1.3% compared to the U-bent duct and the Tmax value decreased by 2.9% compared to the 2-U twisted duct. It has been found that the 4-chamber channel performs better than 1-2-3 and reduces the heat generated on the battery more. In addition, parametric studies performed on the selected channel structure (4-U, 4- chamber) have shown that the Lithium-ion battery pack can be kept in the ideal operating temperature range (20°C-40°C) at different Reynolds numbers for 1C and 2C discharge rates.