Browsing by Subject "Lithium-ion"
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Item Battery Vent Gas Hazard Analysis and Building Deflagration Dashboard Development(2020-09-15) Trejo Martinez, Juan; Ezekoye, Ofodike A.Lithium-ion battery failures can lead the battery cell to undergo what’s known as thermal runaway, resulting in a potentially catastrophic fire or explosion. During a thermal runaway event a series of chemical reactions take place, increasing the cell temperature and resulting in the generation of a flammable gas mixture. The University of Texas Fire Research Group has developed two models to evaluate fire and explosion hazard for lithium-ion batteries using the aforementioned studies. The first model aims to estimate the upper and lower flammability limits, laminar flame speed, and maximum overpressure of the gases released during thermal runaway. While the second model predicts the pressure time history of an explosion. Both of these models are intended to provide a framework for evaluating the overall safety of lithium-ion cells. To enable our researches to perform rapid data analysis as more experimental data becomes available, a web application that presents the above-mentioned models in the form of interactive dashboards was developed and deployed using Python and a framework for building data visualization web applications called Dash. The first part of development was building the application’s layout. The layout of a Dash application is built by assembling a hierarchical tree of components. These components are the building blocks of the application and can come from either the dash_html_components or dash_core_components modules. The second part of development involved creating and wiring up a MongoDB database to the application. This connection allows the application to access and perform operations on the stored data. Finally, deploying the application was done through Heroku, a Platform as a Service that provides the infrastructure and user interface to publish and manage a web application. The two dashboards deployed are the Vent Gas Hazard Analysis dashboard and the Building Deflagration dashboard. The Vent Gas Hazard Analysis dashboard summarizes key gas characteristics such as lower and upper flammability limits, laminar flame speed, and maximum over-pressure, which are essential in quantifying the overall hazard potential or the runaway event. While the Building Deflagration dashboard provides information on how room pressure changes over a period of time during a battery explosion event.Item Development of antimony-based anode systems for lithium-ion batteries(2015-08) Allcorn, Eric Koederitz; Manthiram, Arumugam; Goodenough, John B; Ferreira, Paulo J; Yu, Guihua; Mullins, Charles BThe superior energy storage characteristics of lithium-ion batteries have made them the state-of-the-art battery technology for the past two decades where they have been integral to the proliferation of portable electronics. Efforts to expand their application into the realms of transportation and stationary storage require additional performance enhancements, though. These enhancements will be achieved through the application of advanced new materials such as alloy anodes like antimony. Alloy anodes offer the potential for dramatic enhancement of cell capacity both gravimetrically and volumetrically due to the high lithium content in their lithiated phases. Additionally, their higher operating voltage means that their incorporation should increase cell safety, a key parameter in large-scale applications, by reducing the risk of lithium plating. The primary factor inhibiting the adoption of alloy anodes is their short cycle life brought about by the large volume change they undergo during cycling that leads to crumbling of the active material and drastic capacity loss. To overcome this issue the following mitigation techniques are applied to antimony active materials: (i) use of active-material intermetallics of M[subscript x]Sb (where M = Ni or Fe) instead of pure antimony; (ii) incorporation of active material into reinforcing active/inactive composites with Al₂O₃, TiC, and/or carbon black; (iii) reduction of active material particles to nano-scale. In addition, the use of high-energy mechanical milling allows these methods to be applied with a simple and potentially scalable synthesis procedure and yields high-density final products. The actual safety performance of antimony anodes are also analyzed due to the importance of such parameters in large-battery applications. Because antimony alone without other components is an impractical anode material, the effects on safety and thermal stability of incorporating it into intermetallic and composite structures are also investigated. The advanced nanocomposites developed in this work demonstrate excellent cycle life with good all-around performance parameters that make them viable, safer candidates to replace graphite in next generation lithium-ion batteries. Pure antimony is also shown to offer enhancement in cell safety performance relative to graphite as well, and nanocomposites based upon its use as an active material are able to retain these favorable safety characteristics.Item Electrochemical transport simulation of 3D lithium-ion battery electrode microstructures(2015-10-21) Trembacki, Bradley Louis; Murthy, Jayathi; Moser, Robert D; Roberts, Scott A; Duoss, Eric B; Chen, DongmeiLithium-ion batteries are commonly modeled using a volume-averaged formulation (porous electrode theory) in order to simulate battery behavior on a large scale. These methods utilize effective material properties and assume a simplified spherical geometry of the electrode particles. In contrast, a particle-scale (non-porous electrode) simulation applied to resolved electrode geometries predicts localized phenomena. Complete simulations of batteries require a coupling of the two scales to resolve the relevant physics. A central focus of this thesis is to develop a fully-coupled finite volume methodology for the simulation of the electrochemical equations in a lithium-ion battery cell at both the particle scale and using volume-averaged formulations. Due to highly complex electrode geometries at the particle scale, the formulation employs an unstructured computational mesh and is implemented within the MEMOSA software framework of Purdue’s PRISM (Prediction of Reliability, Integrity and Survivability of Microsystems) center. Stable and efficient algorithms are developed for full coupling of the nonlinear species transport equations, electrostatics, and Butler-Volmer kinetics. The model is applied to synthetic electrode particle beds for comparison with porous electrode theory simulations and to evaluate numerical performance capabilities. The model is also applied to a half-cell mesh created from a real cathode particle bed reconstruction to demonstrate the feasibility of such simulations. The second focus of the thesis is to investigate 3D battery electrode architectures that offer potential energy density and power density improvements over traditional particle bed battery geometries. A singular feature of these geometries is their interpenetrating nature, which significantly reduces diffusion distance. Advancement of micro-scale additive manufacturing techniques has made it possible to fabricate these electrode microarchitectures. A fully-coupled finite volume methodology for the transport equations coupled to the relevant electrochemistry is implemented in the PETSc (Portable, Extensible Toolkit for Scientific Computation) software framework which allows for a straightforward scalable simulation on orthogonal hexahedral meshes. Such scalability becomes important when performing simulations on fully resolved microstructures with many parameter sweeps across multiple variables. Using the computational model, a variety of 3D battery electrode geometries are simulated and compared across various battery discharge rates and length scales in order to quantify performance trends and investigate geometrical factors that improve battery performance. The energy density and power density of the 3D battery microstructures are compared in several ways, including a uniform surface area to volume ratio comparison as well as a comparison requiring a minimum manufacturable feature size. Significant performance improvements over traditional particle bed electrode designs are observed, and electrode microarchitectures derived from minimal surfaces are shown to be superior under a minimum feature size constraint. An average Thiele modulus formulation is presented to predict the performance trends of 3D microbattery electrode geometries. As a natural extension of the 3D battery particle-scale modeling, the third and final focus of the thesis is the development and evaluation of a volume-averaged porous electrode theory formulation for these unique 3D interpenetrating geometries. It is necessary to average all three material domains (anode, cathode, and electrolyte) together, in contrast to traditional two material volume-averaging formulations for particle bed geometries. This model is discretized and implemented in the PETSc software framework in a manner similar to the particle-scale implementation and enables battery-level simulations of interpenetrating 3D battery electrode architectures. Electrode concentration gradients are modeled using a characteristic diffusion length, and results for plate and cylinder electrode geometries are compared to particle-scale simulation results. Additionally, effective diffusion lengths that minimize error with respect to particle-scale results for gyroid and Schwarz P electrode microstructures are determined, since a theoretical single diffusion length is not easily calculated. Using these models, the porous electrode formulation for these 3D interpenetrating geometries is shown to match the results of particle-scale models very well.Item Environmental impacts of onshoring lithium and lithium-ion battery production(2022-07-06) Harner, Zakariah Quinton; Childress, Tristan M.; Chuchla, Richard J. (Richard Julian)Life cycle assessment was conducted to quantify prospective environmental impacts of a transition to onshore supply of lithium battery materials and onshore production of lithium-ion battery cells in the United States. Life cycle assessments were compiled for current lithium raw materials and lithium-ion battery cell supply chain pathways, dominated by a Chinese midstream monopoly on refinement and lithium-ion battery component production, and compared with prospective American-based supply chain pathways. Differences in global warming potential (GWP) (kg of carbon dioxide equivalents), water consumption, and land use of differing supply chain pathways were the primary environmental impacts under comparison and analysis. Both “Traditional” (current) and prospective American supply chain pathways were developed for lithium carbonates, lithium hydroxides, nickel-cobalt-aluminum (NCA) based battery cells, and lithium-iron-phosphate (LFP) based battery cells. Each product was modeled from cradle-to-gate, meaning from raw material extraction through transportation to point of sale. Transition from Traditional lithium carbonate supply chain pathways to American-based pathways resulted in a 66% reduction in the GWP of transportation of refined materials, thanks largely to elimination of the need for cross-Pacific freight shipping. Transition from Traditional supply chain pathways to American-based lithium hydroxide pathways resulted in a 49% reduction in the GWP of electricity usage during refinement when transitioning from Chinese and Japanese electricity grids to United States counterparts, due largely to lower amounts of coal-based electricity generation within the United States electricity grid. During the simulated production of 100 kWh of NCA and LFP-based lithium-ion battery cells, NCA cells were found to produce 11% less GWP than LFP equivalents on average. Utilizing lithium raw materials sourced from the Americas, American based production of NCA and LFP cells was found to produce an average of 13% less GWP than Traditional supply chain pathway counterpartsItem Experimental and computational characterization of thermal runaway propagation in lithium-ion pouch cell arrays(2021-12-01) Kennedy, Robert Wade; Ezekoye, Ofodike A.; Hall, Matthew; Ellzey, Janet; Varghese, Philip; Marr, Kevin COver the past two decades, Lithium-ion (Li-ion) batteries have become ubiquitous in society. Their relatively high energy density, and recharge efficiency have resulted in their mass adoption. With falling prices, batteries have moved from single cell applications to increasingly larger systems comprised of many cells, such as electric vehicles (EVs), and fixed systems used in grid-scale load-leveling and uninterruptible power supplies (UPS). These systems typically have thousands, or tens of thousands, of cells in order to meet the desired capacity and power draw capabilities. Li-ion energy storage systems (ESS) are generally safe. However, Li-ion cells can fail under abnormal conditions potentially resulting in a catastrophic event known as thermal runaway (TR). During this failure process, exothermic reactions within the cell can result in excessive temperatures (∼ 800-1000°C), and produce highly flammable, toxic vented gases. As has been done for legacy battery technologies, such as Lead-acid, it is important to characterize these hazards, and to develop prevention, detection, mitigation strategies for TR and TR propagation. Experiments were conducted with arrays of Li-ion, pouch-format cells of two cathode chemistries: LCO and NMC. These experiments represent pseudo-modules to characterize TR failure propagation. This work makes the assumption that a single cell can and will fail for a specific system. This failure is represented using an external heater applied to one cell on one side of the array. From the initial failure, this work analyzes the failure propagation process, discusses the patterns seen, and evaluates different experimental techniques. One of the key hazards resulting from TR and TR propagation is the previously mentioned vent gas production. This vent gas is primarily composed of hydrogen, carbon dioxide, carbon monoxide, and various hydrocarbons. Altogether the produced vent gas can result in fire if ignited, or an explosion if allowed to accumulate. Furthermore, Li-ion cells have been found to produce sparks and eject relatively hot soot particulates during TR that can result in vent gas ignition. This work characterizes the vent gas release process for the two cell chemistries tested, including the total volume production, rate of release, and gas composition. While more toxic gases have also been detected in trace amounts in Li-ion vent gas, the primary goal of this work is to characterize the TR failure propagation process as it relates to fire and explosion related hazards. Thus, toxic gas characterization is beyond the scope of this work and is left to other studies in the literature. The second hazard from Li-ion TR propagation is the resulting elevated cell temperatures from the internal exothermic reactions. This work discusses the internal reactions responsible for TR proposed in the literature. Furthermore, this work evaluates the effect of a cell’s state of charge (SOC) on these reactions. Experimentally, thermocouples (TCs) were used to measure the temperatures between cells. These experimental data were then used to create and calibrate a computational model for predicting TR propagation in cell arrays of varying SOC. The effect of SOC is significant from the modeled internal kinetics. However, the heat transfer process between cells was found to be the primary challenge in modeling cell-to-cell TR propagation. Finally, the computational model was used to evaluate the performance of thermal separation materials between cells to inhibit cell-to-cell TR propagation. This work found that insulation, and thermal sink layers, i.e. aluminum plates between cells, could slow TR propagation, but may still lead to TR propagation via other modes of heat transfer to the cell array, including heat convection from the produced hot vent gases. Additionally, this work does not fully study the effect of external flaming combustion which was found to accelerate TR propagation in preliminary tests. Thus, external flaming combustion could reduce the efficacy of thermal separation materials between cells. Regardless, the computational model is capable of accurately predicting TR propagation in these arrays without external flaming combustion, and can be used to quickly evaluate several potential mitigation strategies. These modeled mitigation strategies can then be further validated with additional experimental testing.Item Magnetic, electronic, and electrochemical properties of high-voltage spinel cathodes for lithium-ion batteries(2015-05) Moorhead-Rosenberg, Zachary; Manthiram, Arumugam; Goodenough, John B; Zhou, Jianshi; Benedek, Nicole; Hwang, GyeongLithium-ion technology has revolutionized the electronics and electric vehicle industry in the past two decades. First commercialized by Sony in 1991, the lithium-ion battery is composed of three main components: (i) the cathode, (ii) the anode, and (iii) the electrolyte. Graphitic carbon remains the most widely used anode material due to its low voltage vs. the Li/Li+ redox couple and high specific capacity. However, there are several popular cathode materials, including layered oxides, spinel oxides, and polyanion materials. In an effort to increase the energy density of lithium-ion batteries, much focus is given to improving the gravimetric charge capacity and the overall cell voltage. The latter must be accomplished by employing high-voltage cathodes, the most promising of which is the lithium manganese nickel oxide spinel with a specific capacity of 146 mAh/g and a redox voltage of 4.7 V vs. Li/Li+. However, there are still several problems with this material that must be understood and overcome in order to develop high-voltage spinel as a viable commercial cathode. Physical property measurements can reveal the underlying electronic and atomic interactions in the solid in order to better understand high-voltage spinel and its odd behavior. Novel magnetic techniques have been developed, which reliably indicate the degree of Mn-Ni ordering and quantitative determination of the concentration of the Mn3+ ion. Measurements of several physical properties as a function of lithium content were also undertaken to determine the effects of Mn-Ni ordering on the electronic conductivity and the importance of electron-ion interactions. In addition to understanding the physical properties of high voltage spinel, the understanding of the solid state chemistry and unique structure was utilized to realize a new full cell construction technique. The spinel structure offers a unique way to deal with first cycle irreversible capacity loss in full cells stemming from solid-electrolyte interphase (SEI) layer growth on the anode surface. To that end, a novel microwave-assisted chemical lithiation process was developed using non-toxic and air-stable chemicals. New composite anode chemistry was combined with a pre-lithiated spinel cathode to demonstrate the feasibility of this approach to realizing practical next-generation Li-ion cells.Item Synthesis and characterization of nanocomposite alloy anodes for lithium-ion batteries(2012-05) Applestone, Danielle Salina; Manthiram, Arumugam; Goodenough, John; Mullins, Charles; Stevenson, Keith; Meyers, JeremyLithium-ion batteries are most commonly employed as power sources for portable electronic devices. Limited capacity, high cost, and safety problems associated with the commercially used graphite anode materials are hampering the use of lithium-ion batteries in larger-scale applications such as the electric vehicle. Nanocomposite alloys have shown promise as new anode materials because of their better safety due to higher operating potential, increased energy density, low cost, and straightforward synthesis as compared to graphite. The purpose of this dissertation is to investigate and understand the electrochemical properties of several types of nanocomposite alloys and to assess their viability as replacement anode materials for lithium-ion batteries. Tin and antimony are two elements that are active toward lithium. Accordingly, this dissertation is focused on tin-based and antimony-based nanocomposite alloy materials. Tin and antimony each have larger theoretical capacities than commercially available anodes, but the capacity fades dramatically in the first few cycles when metallic tin or antimony is used as the anode in a lithium-ion battery. This capacity fade is largely due to the agglomeration of particles in the anode material and the formation of a barrier layer between the surface of the anode and the electrolyte. In order to suppress agglomeration, the active anode material can be constrained by an inactive matrix of material that makes up the nanocomposite. By controlling the surface of the particles in the nanocomposite via methods such as the addition of additives to the electrolyte, the detrimental effects of the solid-electrolyte interphase layer (SEI) can be minimized, and the capacity of the material can be maintained. Moreover, the nanocomposite alloys described in this dissertation can be used above the voltage where lithium plating occurs, thereby enhancing the safety of lithium-ion batteries. The alloy anodes in this study are synthesized by high-energy mechanical milling and furnace heating. The materials are characterized by X-ray diffraction, scanning and transmission electron microscopies, and X-ray photoelectron spectroscopy. Electrochemical performances are assessed at various temperatures, potential ranges, and charge rates. The lithiation/delithiation reaction mechanisms for these nanocomposite materials are explored with ex-situ X-ray diffraction. Specifically, three different nanocomposite alloy anode materials have been developed: Mo3Sb7-C, Cu2Sb-Al2O3-C, and Cu6Sn5-TiC-C. Mo3Sb7-C has high gravimetric capacity and involves a reaction mechanism whereby crystalline Mo3Sb7 disappears and is reformed during each cycle. Cu2Sb-Al2O3-C with small particles (2 - 10 nm) of Cu2Sb dispersed in the Al2O3-C matrix is made by a single-step ball milling process. It exhibits long cycle life (+ 500 cycles), and the reversibility of the reaction of Cu2Sb-Al2O3-C with lithium is improved when longer milling times are used for synthesis. The reaction mechanism for Cu2Sb-Al2O3-C appears to be dependent upon the size of the crystalline Cu2Sb particles. The coulombic efficiency of Cu2Sb-Al2O3-C is improved through the addition of 2 % vinylethylene carbonate to the electrolyte. With a high tap density of 2.2 g/cm3, Cu6Sn5-TiC-C exhibits high volumetric capacity. The reversibility of the reaction of Cu6Sn5-TiC-C with lithium is improved when the material is cycled above 0.2 V vs. Li/Li+.Item Ultrasonic and vibrational methods to determine changes of state of lithium-ion cells(2023-12) McGee, Tyler Michael; Ezekoye, Ofodike A.; Haberman, Michael R. (Michael Richard), 1977-; Arguelles, Andrea; Khani, HadiLithium-ion batteries (LIBs) are the chosen power source for battery electric vehicles and battery energy storage systems. These high-power, high-capacity applications subject LIBs to challenging operating environments where mechanical, electrical, and thermal abuse is likely. In these applications, thousands to hundreds of thousands of cells are connected in series and parallel, which creates a challenging monitoring problem. The search for improvements to the battery management system (BMS), including new sensing modalities, is a very active and growing field. This work investigates the use of mechanical inspection of lithium-ion batteries using dynamic mechanical loading for state estimation. Ultrasonic inspection is used to monitor cells as they undergo normal charge-discharge cycling and different amounts of thermal loading, sometimes to thermal runaway. By specifically monitoring the ultrasonic signal characteristics of the signal amplitude (SA) and time of flight shift (TOFS), we can monitor changes to the cell's stiffness, density, and attenuation which result from changes in the cell's state of charge (SOC), temperature, or the presence of damage from thermal abuse. We find that ultrasonic signal characteristics warn of impending cell failure up to 25 minutes in advance of traditional monitoring sensors. A transfer matrix model employing a Bloch-Floquet formalism which accounts for the repeating layered scheme of the cell is introduced to explore ultrasonic wave dispersion due to the layered structure and internal losses due to the cell's polymeric components. Experimentally obtained ultrasonic signal characteristics were corroborated with this periodic transfer matrix model (PTMM) which can simulate SA and TOFS by using the appropriate SOC or temperature-dependent material properties of cell components. The PTMM validates experimental measurements, and helps demonstrate which cell components dominate the characteristics of ultrasonic wave propagation in the thickness direction of LIB pouch cells. The results from US inspection demonstrate its applicability to provide advanced warning of cell failure and also to detect the presence of damage from previous thermal abuse. The same chemo-mechanics that drive changes in the cell's ultrasonic response should also affect the cell's modal response. One can imagine implementing modal testing on cell packs as a part of routine maintenance, or making use of ambient vibrations as the excitation for modal testing in applications like BEVs . As such, this work also explores the viability of vibrational inspection for state estimation, focusing primarily on SOC and state of health (SOH) estimation. The surface velocity of lithium-ion pouch cells confined in a fixed-fixed configuration is measured with a scanning laser Doppler vibrometer (SLDV) while the cells are subjected to base excitation using an electrodynamic a shaker. SLDV scans are performed after the cell has been charged or discharged to specific SOC and repeated across numerous cycles. Results from these experiments show that the modal frequency of a cell shifts towards higher frequency with increasing SOC. These results were corroborated with an effective material model of the cell which was created with multiscale homogenization of the cell's components including their microscale heterogeneity. This material model is created using material properties of constituents at full charge and at full discharge, and is input to a finite element simulation of the resonance frequency of the cell. We find good agreement between the resonance frequency predicted by the multiscale model and transmissibility measurements at 0% and 100% SOC. The experimental results for continued cycling showed an increase in modal frequency at the fully charged and fully discharged states with cell aging. While identifying the chemo-mechanical cause of the changing cell modal response with aging remains a challenge, the correlation between SOH and modal response illustrates how the technique can be used for both SOC and SOH estimation.Item Ultrasonic inspection of lithium-ion batteries for early detection of thermal runaway(2022-05-02) Neath, Barrett James; Haberman, Michael R. (Michael Richard), 1977-; Ezekoye, Ofodike A.As efforts to establish a clean, renewable energy infrastructure are growing, the demands for safe and reliable energy storage systems are growing as well. Despite their widespread application in low-power consumer electronics, lithium-ion batteries are struggling to match the performance needs required for high-power applications, including electric vehicles and grid energy storage. At the same time, traditional battery management systems (BMS) relying solely on voltage, current, and temperature measurements have failed to keep up with the dynamic needs of the industry, and, as a result, the electric vehicle market has been plagued by headlines of lithium-ion battery fires and explosions. Therefore, in order to ensure the safety and reliability of lithium-ion battery systems in high-power applications, accurate health monitoring for catastrophic failure prevention is of the utmost importance. This thesis explores the viability of ultrasonic inspection for early damage detection in cells undergoing thermal abuse. Specifically, initial studies are reported on the use of ultrasonic wave measurements for detection of cell damage while simultaneously monitoring voltage, current, temperature, and mechanical clamping force under varying electrical, mechanical, and thermal loading conditions. Time- and frequency-domain features of the acoustic signals are monitored for excitation frequencies of 0.1–1 MHz transmitted along two propagation paths. Correlations between changes in time of flight and signal amplitude with variations in electrical, mechanical, and thermal loading conditions are presented for cells subjected to electrochemical cycling and thermal abuse scenarios. Early ultrasonic indicators of damage evolution in the cells are presented, compared with traditional detection methods, and discussed with respect to excitation frequency, propagation path, and known damage mechanisms in lithium-ion batteries. The results presented in this work highlight the ability of ultrasonic waves to detect internal mechanical changes during battery operation and illustrate the predictive capability of ultrasonic inspection for damage detection up to thirty minutes in advance of cell rupture.Item Ultrasonic inspection of lithium-ion batteries to determine battery safety(2019-12) McGee, Tyler Michael; Haberman, Michael R. (Michael Richard), 1977-; Ezekoye, Ofodike AElectric vehicles and energy storage systems are becoming increasingly viable from an operational and financial perspective. The most popular choice for the power source for these applications is the lithium-ion battery due to its high volumetric energy density and long cycle life. While lithium-ion batteries have been used in low-power applications for many years, electric vehicles and energy storage systems are high-power applications which put additional operating stresses on the battery cells and the battery management system (BMS) that ensures operational safety. Along with this change in application, lithium-ion batteries are also being subjected to market pressures to increase single-cycle life and to reach full charge faster. BMS have not kept up with these changing applications and market pressures, which has lead to some battery cells failing catastrophically. This thesis explores the viability of ultrasonic inspection to determine battery safety in the event of an overcharge. Two detection criteria were investigated in this thesis: whether an overcharge event could be detected while it was occurring and whether ultrasonic inspection could detect that a battery had previously undergone an overcharge event. The results of these tests showed two consistent indicators of overcharge while it occurred, one around 105% nominal voltage and one around 114% nominal voltage. Both of these indicators signal overcharge well before a catastrophic event. Results also indicated that overcharge can be detected during a normal cycle after the overcharge event occurred