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Document Type

Thesis - University Access Only

Award Date

2017

Degree Name

Master of Science (MS)

Department

Electrical Engineering and Computer Science

First Advisor

Qiquan Qia

Second Advisor

Huitian Lu

Keywords

1D-electrochemical model, Charge-discharge behavior, Coulumb's counting, Kinetic Monte Carlo, SOC, SOH, Solid-Electrolyte Interface layer

Abstract

The accurate model on the growth of Solid-Electrolyte Interface (SEI) layer of Lithiumion batteries is used to study the capacity fade, ageing, and cycling life and provides significant information to ensure the battery safety. In this work, the model for SEI layer dynamics is developed using the Kinetic Monte Carlo approach, in which four major dynamical processes including adsorption, absorption, diffusion, and passivation are described by their individual rates, and determined from chemical and physical properties of materials used in the battery. Total cycle numbers to be simulated determine the number of Kinetic Monte Carlo steps. The formation of a passive SEI layer with variable thickness was simulated based on a mathematical model of SEI dynamics. The interfacial resistance of every cycle was calculated with the varying coverage and thickness of SEI layer. The simulation results were found consistent with the literature where thickness increased proportionally to the square root of the time (cycle). The interfacial resistance obtained from the simulation was used in the 1D- electrochemical model, to predict the chargedischarge behavior of the battery with the varying resistance. The State of Charge (SOC) was also calculated using Coulomb’s counting and impedance spectroscopy method, whereas the State of Health (SOH) was determined through the measurement of internal resistance and capacity. After the coupling of SEI layer model to the 1D electrochemical model, the results obtained from the simulation were validated with experimental results.

Library of Congress Subject Headings

Lithium ion batteries -- Materials.
Electrolytes.
Electric capacity.
Monte Carlo method.

Description

Includes bibliographical references (pages 97-101).

Format

application/pdf

Number of Pages

119

Publisher

South Dakota State University

Rights

In Copyright - Educational Use Permitted
http://rightsstatements.org/vocab/InC-EDU/1.0/

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