An Analysis of Li-ion Traction Battery System Thermal Simulation Based on Simplified Pipeline Fluid Model and Liquid Cooling Enhancement

In recent years, while the “decarbonized economy” is being practiced globally, the ownership of new energy vehicles has been increasing rapidly. During the development of new energy vehicles, the design of thermal management systems has been underlined. Developing an effective and energy-saving battery thermal management system is an important factor in guaranteeing the high performance of new energy vehicles. This article dissects the electrothermal coupling performance of the battery pack based on finite element methodology and proposes a liquid cooling layout of the battery cooling system with an optimized cooling effect. The research reveals that: (1) By constructing a multi-dimensional electrothermal coupling model consisting of a one-dimensional electrochemical model, one-dimensional pipeline fluid model, and three-dimensional heat transfer model, the electrothermal performance of the battery pack can be simulated efficiently and further improvement can be established on its liquid-cooling system. (2) During the discharging process, the central temperature of the battery pack is significantly higher which reaches 45°C with a 2C discharging rate. (3) The liquid-cooling pipelines on the side can efficiently reduce the temperature of the battery pack. With an increasing flow rate of the coolant, the average temperature of the battery pack is reduced while the maximum temperature difference is increasing instead; with a certain flow rate, increasing the radius of the pipe would lead to a decrease in maximum temperature and the maximum temperature difference within the battery pack.