Document Type

Thesis - Open Access

Award Date

2019

Degree Name

Master of Science (MS)

Department / School

Mechanical Engineering

First Advisor

Huitian Lu

Abstract

The scope of the current research is to reduce the temperature distribution area in Li-ion cell and the battery pack with respect to time in battery design, using CFD technology (Computational Fluid Dynamics) in ANSYS fluent. A 3D model was design in CAD software (CATIA) and analyzed in ANSYS fluent to study the thermal behavior of the designed battery pack. An analytical thermal model was generated to evaluate the heat generation rate passing throughout the battery pack. The battery pack were analyzed and simulated on two different designs. One battery design is modeled with and without insulation (superwool EST compression paper) between the cells and the other design is with and without PCM (phase change material). We have two materials, general insulation with low thermal conductivity and PCM with high thermal conductivity to observe thermal behavior of the battery. The outcome of this analytical model was employed under the convective boundary conditions of the battery design in CFD simulation to identify the thermal behavior. The achieved results show the comparison between insulation and PCM that gives much more achievable performance of temperature distribution evaluation with PCM than that with insulation material, as PCM absorbs the rise in temperature and procrastinate to attain the defined maximum temperature with respect to time. Simulation results carried under the convective temperature as for PCM at 310 K, 400 K, with different intervals of time on five-unit (5s2p: 5-in-series of 2-in-paralle). Temperature with insulation material model at 310 K, 400 K, on five-unit (5s2p: 5-in-series of 2-inparallel). Heat created as a function of current I (ampere) is passed through the tabs and throughout the center of each cell of the battery. The phase change duration depends particularly on the density, thermal conductivity, specific heat of the PCM material. Phase change material can reject much heat from cell to environment. The purpose of the PCM design in battery is to limit the supply of heat, in time, to the PCM and thus extends the phase change duration and increase the heat transfer to the environment. The simulation shows the maximum temperature are reduced by employing PCM over the surface of the battery. PCM employed with thickness of 0.32 mm and insulation thick material of 3.125 mm. We have employed two layers of PCMs on each surface of the cell to sustain the maximum temperature, double layer of PCMs on both surfaces of Li-ion cell will be more efficient than one surface. A thin PCM thickness around the cell, in turn, provides better temperature distribution due to heat generated in the cell. When a PCM with high thermal conductivity is employed for Li-ion battery, the temperature dissipated becomes more uniform as compared to insulation material. The achieved results show the comparison between insulation and PCM that gives achievable performance of temperature distribution and reduces the initial rise, as PCM absorbs the heat and reduce temperature distribution area. The purpose of the PCM design in battery is to absorb the supply of heat, in time and thus extends the phase change duration and increase the heat transfer to the environment.

Library of Congress Subject Headings

Lithium ion batteries.
Lithium ion batteries -- Thermal properties.
Lithium ion batteries -- Thermal conductivity.
Electronic apparatus and appliances -- Temperature control.

Format

application/pdf

Number of Pages

102

Publisher

South Dakota State University

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Rights Statement

In Copyright