Document Type

Thesis - Open Access

Award Date

2017

Degree Name

Master of Science (MS)

Department / School

Electrical Engineering and Computer Science

First Advisor

Qiquan Qiao

Keywords

battery modeling, capacity fade, Lithium ion (Li-ion), porous current collector, solid electrolyte interphase (SEI), state of health (SOH)

Abstract

Lithium ion (Li-ion) batteries are primary energy storage devices especially in electronic gadgets, electric vehicles and for stationary storage of intermittent renewable energy. These applications demand durable Li-ion batteries with higher energy density. Energy density can be increased either by finding novel electrode materials or by modifying the existing design of the battery. The electrode materials or modified design should not only increase energy density, but also should control the capacity fading of the battery. In this work, existing mathematical model of Li-ion battery was adjusted in the case of the porous current collector. The discharge performance and capacity fading of the porous current collector based Li-ion battery was compared with non-porous current collector Li-ion battery. The electrode averaged model (EAM) was used to simulate the discharge performance of the battery. The capacity fade was compared by comparing the film growth, change of initial electrode state of charge (SOC) and change in solid phase diffusion coefficient with cycling. Both simulation and experimental results have shown the porous current collector based Li-ion battery achieves greater than the theoretical specific capacity of electrode active materials for the first few cycles of operations. In this work, Lithium titanate was considered as an electrode active material which has a theoretical specific capacity of 175 mAh/g. Simulation and experiment have predicted specific capacities of 238 mAh/g and 235 mAh/g respectively in the case of the porous current collector. Simulation result showed the porous current collector Li-ion batteries reaches the end of useful life after 100 more cycles than the non-porous current collector batteries under similar conditions of operation.

Library of Congress Subject Headings

Lithium ion batteries.
Mathematical models.
Storage batteries -- Materials.
Energy storage.
Electric capacity.

Description

Includes bibliographical references (pages 75-81)

Format

application/pdf

Number of Pages

97

Publisher

South Dakota State University

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Rights Statement

In Copyright