Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 107 for “"Cycle Life"”.
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The effect of active mass thickness on the cycle life of low-antimony lead-alloy spine employed in deep-cycle batteries
The cycle life of conventional starting-lighting-ignition (SLI) lead-acid batteries with low-antimony lead-alloy grids is reduced when subjected to repetitive deep-discharge cycling. Reduced cycle life is caused by the rich layer of lead sulfate formed in the corrosion layer interface (Barrett et …
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STUDYING THE EFFECTS OF NEW ADDITIVE MATERIALS FOR THE IMPROVEMENT OF THE CAPACITY AND CYCLE LIFE PERFORMANCE OF THE LEAD-ACID BATTERY
… is hampered by secondary reactions during the cycle life such as corrosion and gassing.</p> <p>Lead-acid batteries were investigated and improved through several different approaches: an alternative electrolyte to mitigate secondary reactions, graphite additives to improve positive active mass …
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Fatigue Life Prediction of Edge-Welded Metal Bellows Using Neural Networks and Multiple Linear Regression
… ongoing challenge: the prediction of an accurate cycle life. Current methods rely on physical leak detection to determine a bellow's cycle life to failure. It is known, however, that crack initiation begins many cycles before a leak path is present. Bellows manufacturers require a method for …
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Internal resistance variances in lithium-ion batteries and implications in manufacturing
… with IR as a function of cycling, models the cycle life of a simple battery pack of two parallel-connected cells that start off as unbalanced, and validates it with experimental data from cycle life testing of parallel-connected LiFePO₄ cell groups. Experimental results from samples of …
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In situ studies of surface reactions affecting Li-ion battery failure
… has been dedicated to improving the safety and cycle life of Li-ion batteries. Unfortunately, many of the mechanisms and fundamental atomistic processes governing the degradation and failure of Li-ion batteries remain poorly understood. Capacity fade in commercially relevant systems can broadly …
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Flexible Supercapacitors Utilising the Multifunctional Rôle of Ionic Liquids
… characteristics of high power density, long cycle life and high efficiency under considerable physical deformation.<br/><br/>An innovative one-pot synthesis to fabricate electronically conducting polymer-biopolymer composites films such as polypyrrole-cellulose composites that are …
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Machine learning for applications in chemical and biological engineering
… the task of prediction lithium-ion battery cycle life. Cycle life is defined as the number of charge and discharge cycles the battery undergoes before 80% capacity fade. Several, difficult to identify factors can contribute to capacity fade. Even in batteries with the same chemistry, …
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Design and Electrochemical Performance of Sodium-Based Batteries
… including lower energy capacity and reduced cycle life, which restrict their viability for long-term use. This thesis addresses several critical challenges faced by SBBs and explores new strategies for enhancing their performance and viability for large-scale applications. First, a …
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Conducting polymer actuators : temperature effects
… Actuation at these temperatures can decrease cycle life by as much as 20x. Excessive heating without actuation can also result in poor actuator performance. Impedance spectroscopy coupled with electro-mechanical analysis highlighted previous results and also showed an improved frequency …
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Investigation of Alkali Metal-Host Interactions and Electrode-Electrolyte Interfacial Chemistries for Lean Lithium and Sodium Metal Batteries
… the electrodeposition capacity improved the cycle life with 3 mAh cm-2 areal capacity and 2% vinylene carbonate (VC) electrolyte additive gave the best cycle life before reaching a state of "rapid cell failure". Increasing the electrodeposition rate reduced cycling stability and had a faster …
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Dynamic modelling and simulation of the all-vanadium redox flow battery
… likely to meet the required energy efficiency, cycle life and cost structure. The widespread commercialization of the vanadium redox flow battery will only be realized however, if battery operation can be optimised to achieve the necessary cycle life and cost reduction of key components are …
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In-situ investigation of lithium dendrite growth and its interactions with a polymer separator in a lithium metal cell
… dendrite growth can negatively affect battery cycle life and safety. Observing the dendrite growth process and revealing its interaction with other components is necessary to improve battery safety. This study uses a transparent optical cell to directly observe the dendrite growth process, …
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Thermoelectrochemical model for RFB with an application at a grid level for peak shaving to reduce cost of the total electricity
… of services.Desirable characteristics are long cycle life, high efficiency, and high energy density.A key challenge for aqueous redox flow battery systems is thermal sensitivity. Oper-ating temperature impacts electrolyte viscosity, species solubility, reaction kinetics,and efficiency. Systems …
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A multistage-constant-current, temperature-controlled, health-conscious fast charging algorithm for lithium-ion batteries
… charging can adversely affect the health and cycle life of the battery due to excessive temperature rise resulting in accelerated degradation of the battery chemistry. Especially in subzero conditions, the chemical reactions are much slower, resulting in increased internal impedance. This …
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Minimal Constraint and Precision Placement in Cyclic Testing of High Life-Cycle Products
… can both pass high amperage and undergo a high cycle life needs to occur. The development of these electrical contacts is a highly experimental process, and thus establishing a method and test equipment to determine the physical and electrical characteristics of these contacts over their …
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Insights on the synthesis, properties, and performance of high-nickel layered oxide cathodes
… necessitates higher-energy-density, longer-cycle-life LIBs, and of the available paths forward, advancements in cathode material are the most attainable in the near future. Among the established cathode materials, high-nickel layered oxides, LiNiₓM₁₋ₓO₂ (M = Mn, Al, Co, etc.), with greater …
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Fundamental understanding and materials design approaches for lithium-oxygen electrochemical energy storage
… the electrode during cycling, and find that poor cycle life can be attributed to gradual accumulation of parasitic Li₂CO₃ promoted by reactivity of the carbon substrate. Finally, we study the influence of Li₂O₂ discharge rate-dependent structure and surface chemistry on the oxidation kinetics to …
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Understanding Failure Mechanisms using Multi-Scale Analyses to Improve the Performance of Zinc Metal and Lithium-ion Batteries
… to increase depth of discharge and extend cycle life of Zn alkaline batteries.</p> <p>Another limitation of many rechargeable batteries is the operating temperature window. Commonly, thermal management systems are implemented to maintain batteries at optimal temperatures. However, these …
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Neural Network Fatigue Life Prediction in 7075-T6 Aluminum from Acoustic Emission Data
… in aluminum fatigue specimens and to use early cycle life AE data to predict failure in such members. An AE data acquisition system coupled with a Kohonen self organizing map and a back propagation neural network were used to perform the analysis. AE waveforms were recorded during fatigue …
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Design and Analysis of End-Effector Systems for Scribing on Silicon
… and fatigue analysis to determine mechanism cycle life. This thesis also investigates the significance of mechanical factors on the chemomechanical scribing process using the compliant end-effector. The factors examined are scribing force, scribing speed, tip geometry, wafer orientation, and …
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