Spelling suggestions: "subject:"in_operando measurements"" "subject:"operando measurements""
1 |
VARIABLE C-RATE IN-OPERANDO BATTERY RUL PREDICTION VIA EDGE-CLOUD ENABLED DEEP LEARNING IN AGNOSTIC BMSJaya Vikeswara Rao Vajja (19332370) 05 August 2024 (has links)
<p dir="ltr">Applications of Lithium-ion batteries (LIBs) are so widely spread from transportation like electric vehicles to portable storage devices. This is mainly due to their lighter weight and smaller size with higher energy density when compared to Lead-acid, Nickel Cadmium (Ni-Cd), and other batteries. One of the applications of LIB includes electric propulsion in-air like quadcopters. These electrically-propelled vehicles have diverse applications including risky jobs like wildlife management, search and rescue, and jobs that can be automated such as delivery of smaller packages, urban planning, and so on. These electrically-propelled vehicles produce heat around the LIB which leads to thermal abuse of the battery. Also, there are often cases where LIB undergoes different abuse conditions in-air when operating these vehicles. Present battery BMSs are highly accurate but require edge and cloud with a deep learning model to safely operate quadcopters in the air. In the work, we present a BMS capable of edge-cloud data transfer with a deep-learning model to predict the RUL of the battery. Benchmark differences between data collected on-ground and in-air are presented for comparison. It turns out that the temperature collected in the air is less than the temperature on the ground when different current profiles are experimented on different batteries used in quadcopters. This study helps in the improvement of BMS with edge-cloud and deep-learning models and helps in understanding the behavior of battery in-air.</p>
|
2 |
Electrochemical Storage of Lithium in Silicon - Morphological Analysis from the Atomistic Scale to the MacroscaleRonneburg, Arne 26 May 2021 (has links)
Die experimentellen Daten können bei Dr. Sebastian Risse, Helmholtz-Zentrum Berlin, eingesehen werden. / Silizium-Elektroden werden aufgrund ihrer um eine Gröÿenordnung höheren Kapazität als mögliches Elektrodenmaterial in Lithium-Ionen-Batterien betrachtet. Diese Kapazität geht jedoch mit einer Volumenausdehnung von bis zu 310 % einher. Dies begünstigt einen schnellen Kapazitätsabfall und ein kontinuierliches Wachstum der SEI-Schicht. Ziel dieser Arbeit ist es daher, die Morphologie-Änderung der Siliziumelektrode während des Lithiierungs-Prozesses besser zu verstehen unter Nutzung von operando-Methoden
Im ersten Teil wurde Neutronenreflektometrie (NR) genutzt, um die Morphologie-Änderung auf der Nanometerskala einer Siliziumelektrode zu untersuchen. Das Wachsen/Schrumpfen der lithiierten Zone im Silizium wurde beobachtet. Auf der Oberfläche der Elektrode wächst im delithiierten Zustand eine Grenzschicht, welche die Lithiierung verhindert. Nachdem diese Schicht aufgelöst ist, kann Lithium eingelagert werden.
Im zweiten Teil wurde operando Röntgen- Phasenkontrast-Radiographie genutzt. Ein rechteckiges Riss-Gitter wurde dabei im delithiierten Zustand beobachtet, welches sich während der Lithiierung schließt. Dieses Gitter ist entlang der Kristallachsen des Siliziums orientiert. Im nächsten Zyklus entsteht das Gitter am selben Ort wieder, und breitet sich mit steigender Zyklenzahl über die Elektrode aus.
Im dritten Teil wurde der Einfluss einer künstlichen Grenzschicht auf die Lithiierung untersucht. Erneut wurde NR genutzt. Die künstliche Schicht verringert das Wachstum der SEI-Schicht, unterdrückt es jedoch nicht komplett. Nach 2 Zyklen ist die Grenzschicht degradiert, und Seitenreaktionen können beobachtet werden. / Silicon electrodes receive great interest as potential electrode material in lithium-based batteries
due to their one order of magnitude higher capacity. This is accompanied by a volume expansion of up to 310 %, leading to an accelerated capacity loss of the electrodes. The volume expansion creates mechanical stress, leading to fracturization of the electrode and the continuous growth of the solid-electrolyte-interphase (SEI) layer under the consumption of active material.
The aim of this thesis is to investigate the morphological changes of silicon electrodes during lithiation/ delithiation. Especially operando-techniques are well-suited to investigate these morphological changes since they allow us to precisely link structural data and the electrochemical state.
The first project uses operando neutron reflectometry (NR) and in-situ electrochemical impedance spectroscopy (EIS) to analyze the morphology change of the silicon surface on the nanometer-scale. The growth and shrinkage of the lithiated layers within the electrode as well as the lithium concentration was determined with this method. An SEI-layer forms on top of the silicon electrode in the delithiated state, which hinders the lithium uptake in the initial part of the subsequent lithiation.
The second project analyzes the morphology-change of the electrode on the µm-scale. Here the
fracturization of the silicon electrode is investigated by operando X-ray phase-contrast radiography. A rectangular fracturization pattern was observed during the second half of the delithiation, which vanished again during the lithiation.
The third project investigates the influence of an artificial coating layer on the lithiation process. Again operando NR was chosen as analysis tool. The artificial coating decreased the formation of the SEI-layer within the first cycles, but did not suppress it completely. However, this layer degraded already in an early stage of cycling, resulting in the occurrence of side reactions afterward.
|
Page generated in 0.0889 seconds