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- All Subjects: Electric Vehicles
Description
Lithium ion batteries are quintessential components of modern life. They are used to power smart devices — phones, tablets, laptops, and are rapidly becoming major elements in the automotive industry. Demand projections for lithium are skyrocketing with production struggling to keep up pace. This drive is due mostly to the rapid adoption of electric vehicles; sales of electric vehicles in 2020 are more than double what they were only a year prior. With such staggering growth it is important to understand how lithium is sourced and what that means for the environment. Will production even be capable of meeting the demand as more industries make use of this valuable element? How will the environmental impact of lithium affect growth? This thesis attempts to answer these questions as the world looks to a decade of rapid growth for lithium ion batteries.
ContributorsMelton, John (Author) / Brian, Jennifer (Thesis director) / Karwat, Darshawn (Committee member) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description
Lithium titanium oxide (LTO), is a crystalline (spinel) anode material that has recently been considered as an alternative to carbon anodes in conventional lithium-ion batteries (LIB), mainly due to the inherent safety and durability of this material. In this paper commercial LTO anode 18650 cells with lithium cobalt oxide (LCO) cathodes have been cycled to simulate EV operating condition (temperature and drive profiles) in Arizona. The capacity fade of battery packs (pack #1 and pack#2), each consisting 6 such cells in parallel was studied. While capacity fades faster at the higher temperature (40°C), fading is significantly reduced at the lower temperature limit (0°C). Non-invasive techniques such as Electrochemical Impedance Spectroscopy (EIS) show a steady increase in the high-frequency resistance along with capacity fade indicating Loss of Active Material (LAM) and formation of co-intercalation products like Solid Electrolyte Interface (SEI). A two-stage capacity fade can be observed as previously reported and can be proved by differential voltage curves. The first stage is gradual and marks the slow degradation of the anode while the second stage is marked by a drastic capacity fade and can be attributed to the fading cathode. After an effective capacity fading of ~20%, the battery packs were disassembled, sorted and repackaged into smaller packs of 3 cells each for second-life testing. No major changes were seen in the crystal structure of LTO, establishing its electrochemical stability. However, the poor built of the 18650-cell appears to have resulted in failures like gradual electrolytic decomposition causing prominent swelling and failure in a few cells and LAM from the cathode along with cation dissolution. This result is important to understand how LTO batteries fail to better utilize the batteries for specific secondary-life applications.
ContributorsWadikar, Harshwardhan (Author) / Crozier, Peter (Thesis advisor) / Wang, Qing H (Committee member) / Nian, Qiong (Committee member) / Arizona State University (Publisher)
Created2019
Description
In March 2019, the United Nations Intergovernmental Panel on Climate Change (IPCC) released a report describing the critical importance of the next decade in mitigating the effects of climate change. From a consumer perspective, the most impactful method of reducing greenhouse gas emissions is by altering and/or reducing usage of personal and public transportation. Despite the significant technological advances in vehicle electrification, vehicle mileage, and hybrid technology, there is a gap in analysis performed about the relationship between oil prices and electric vehicle sales. This can be largely attributed to the large variation in oil and gas prices within the last decade and the short timeframe in which electric vehicles have been available to the average consumer. In addition to oil prices, significant driving factors of consumer electric vehicle purchases include battery range, availability and accessibly of charging infrastructure, and tax incentives. While consumers clearly have a significant role to play in driving electric vehicle sales, by virtue of the time commitment required to research and develop these emerging technologies, manufacturers have an arguably greater role in determining the market share EVs possess. The concept of “market disruption” versus “market replacement” is an intriguing explanation for the failure of electric vehicles, which as of early 2019 held a market share of less than 2%, to become the primary mode of transportation for most Americans, despite their wide-ranging financial and societal benefits, which will be a key challenge for the industry to overcome in the years to come.
ContributorsStout, Julia (Author) / Jennings, Cheryl (Thesis director) / Metcalfe, Carly (Committee member) / Industrial, Systems & Operations Engineering Prgm (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05