Document Type

Thesis - Open Access

Award Date

2024

Degree Name

Master of Science (MS)

Department / School

Mechanical Engineering

First Advisor

Zhong Hu

Abstract

Electric vehicles (EVs) rely heavily on lithium batteries due to their high energy density, despite their tendency to generate excess heat during operation. Managing this heat is crucial for safety and performance. Battery Thermal Management Systems (BTMS) are essential for maintaining optimal battery temperature and mitigating risks like short circuits. This article examines various cooling methods for BTMS, including air and liquid cooling, and discusses the selection of cooling media and layout configurations within battery packs (BPs). It also highlights the importance of combining multiple cooling methods for efficient heat dissipation. Emerging technologies like Phase Change Materials (PCMs) show promise for enhancing BTMS effectiveness. Combining different cooling strategies offers a balanced approach between cost and efficiency. Based on the above review, this thesis investigates the thermal properties of BP with composite BTMS. A battery-pack (BP) thermal model containing 3 single cells was developed and numerically solved using coupled fluid governing equations. Generate the mesh was done using Fluent Meshing. Subsequently, the model was imported into Fluent and the k-ε model was used to solve turbulence. Various parameters of the coolant such as temperature and inlet mass flow rate are considered. The results show that a composite BTMS utilizing both air and liquid cooling enhances the cooling performance compared to a single BTMS. Air can significantly reduce thermal unevenness on the battery surface due to increased wind exposure. However, its effectiveness in reducing the temperature difference within the BP is limited. Lowering the coolant temperature can significantly reduce the maximum temperature of the BP, and increasing the flow rate within a certain range can also slightly reduce the maximum temperature of BP. At the same time, the cooling capacity of BTMS when BP is used as a battery module (BM) is simulated. Since the BTMS is independently placed in the MP, the maximum and average temperatures of the battery are basically unaffected when installing it at either the edge or center has minimal effect on the maximum and average temperatures of the BP. This study may help in the design of efficient BTMS.

Publisher

South Dakota State University

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Rights Statement

In Copyright