Multi-Objective Optimization of Structural Parameters of Air-Cooled System for Lithium Battery Pack Based on Surrogate Model

Abstract

The new energy electric vehicle, which takes clean electric energy as the main driving force, has no pollutants and exhaust emissions during its operation. And has a higher energy utilization ratio than the fuel locomotive. Therefore, electric vehicles have been widely developed in recent years. The maximum temperature and temperature consistency of battery pack in electric vehicle have great influence on the life and safety of battery. In this paper, the thermal management system of lithium battery pack was taken as the research object. The temperature distribution and uniformity of battery pack under different heat dissipation conditions were analyzed based on computational fluid dynamics (CFD). The multi-objective optimization method of battery pack thermal management system was carried out by combining sur-rogate model with fast non-dominated sorting genetic algorithm (NSGA-II). The maximum temperature of the battery pack obtained from candidate point 1 is 310.72K, which is 4.99K lower than the initial model temperature, and the temperature standard deviation is 0.76K, with a reduction rate of 51.9%. Experiment results showed that maximum difference between the optimized and experimental value of the maximum temperature is 0.8K, and the error was within 1K. Therefore, the multi-objective optimization method proposed in this paper has high accuracy.

Effect of welding conditions on the deformation of lithium battery pack of aluminum alloys

“…[4][5][6] During the manufacturing processes of lithium battery, many Li-ion cells were packaged into different shapes for energy storage system in the electric vehicles, designed to achieve higher cost efficiency and lower tendency of thermal aging. [7][8][9] The battery cell packaging during the development of an electric vehicle battery pack is important to deliver optimum performance of the lithium battery packs that protects the battery modulus.…”

“…10,11 Aluminum alloys are commonly used in the lithium battery packs because of the enough strength and lightweight requirement. 8,11,12 Due to the advantage of high-efficient welding process, metal insert gas (MIG) welding is widely applied in the manufacturing process of aluminum alloys. [13][14][15] However, large welding deformation was found in the lithium battery pack of aluminum alloys, due to the low stiffness of aluminum alloys and high heat input during the welding process.…”