Multiscale Analysis and Safety Assessment of Fresh and Electrical Aged Lithium-Ion Pouch Cells Focusing on Mechanical Behavior

Analyzing the impact of electrical aging on the lithium-ion cell’s mechanical behavior and safety is an important factor to assess the crash safety of electric vehicles during their lifetime. In this study, fresh and electrical aged state-of-the-art NCM pouch cells were investigated. Aged cells, whi...

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Main Authors: Marvin Sprenger, Norbert Dölle, Florian Schauwecker, Marco Raffler, Christian Ellersdorfer, Wolfgang Sinz
Format: Article
Language:English
Published: MDPI AG 2022-01-01
Series:Energies
Subjects:
Online Access:https://www.mdpi.com/1996-1073/15/3/847
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author Marvin Sprenger
Norbert Dölle
Florian Schauwecker
Marco Raffler
Christian Ellersdorfer
Wolfgang Sinz
author_facet Marvin Sprenger
Norbert Dölle
Florian Schauwecker
Marco Raffler
Christian Ellersdorfer
Wolfgang Sinz
author_sort Marvin Sprenger
collection DOAJ
description Analyzing the impact of electrical aging on the lithium-ion cell’s mechanical behavior and safety is an important factor to assess the crash safety of electric vehicles during their lifetime. In this study, fresh and electrical aged state-of-the-art NCM pouch cells were investigated. Aged cells, which were cycled electrically to 90% state of health, under laboratory conditions in electric vehicle battery modules were used. The used charging/discharging strategy represents real customer behavior based on accelerated driving profiles. First, it is shown that electrical aging has a significant influence on the anodes’ and separators’ mechanical properties, which had a lower mechanical strength and stiffness under tension. Additionally, quasi-static cylindrical indentation and three-point bending tests were performed to investigate aging effects on cell level at varying state of charge (SOC). Aged cells with 0% SOC showed a right-shifted force–displacement curve and a 29% lower maximum force compared to fresh cells. Fully charged, aged cells reached a similar maximum force to fresh cells, but faster temperature increase and higher temperature peaks after internal short circuit. Inductively coupled plasma optical emission spectrometry analyses confirmed an increased lithium content on the anode surface, which is indicated in literature as a reason for the increased exothermic reaction of the aged cells. The results indicate a higher safety risk for the aged investigated pouch cells under mechanical loads based on their changed mechanical properties and thermal runaway behavior.
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spelling doaj.art-60cc0339d4594c2386455ff512ce495d2023-11-23T16:20:53ZengMDPI AGEnergies1996-10732022-01-0115384710.3390/en15030847Multiscale Analysis and Safety Assessment of Fresh and Electrical Aged Lithium-Ion Pouch Cells Focusing on Mechanical BehaviorMarvin Sprenger0Norbert Dölle1Florian Schauwecker2Marco Raffler3Christian Ellersdorfer4Wolfgang Sinz5Mercedes-Benz AG, HPC X631, 71059 Sindelfingen, GermanyMercedes-Benz AG, HPC X631, 71059 Sindelfingen, GermanyMercedes-Benz AG, HPC X631, 71059 Sindelfingen, GermanyVSI—Institute of Vehicle Safety, University of Technology Graz, Inffeldgasse 23/I, 8010 Graz, AustriaVSI—Institute of Vehicle Safety, University of Technology Graz, Inffeldgasse 23/I, 8010 Graz, AustriaVSI—Institute of Vehicle Safety, University of Technology Graz, Inffeldgasse 23/I, 8010 Graz, AustriaAnalyzing the impact of electrical aging on the lithium-ion cell’s mechanical behavior and safety is an important factor to assess the crash safety of electric vehicles during their lifetime. In this study, fresh and electrical aged state-of-the-art NCM pouch cells were investigated. Aged cells, which were cycled electrically to 90% state of health, under laboratory conditions in electric vehicle battery modules were used. The used charging/discharging strategy represents real customer behavior based on accelerated driving profiles. First, it is shown that electrical aging has a significant influence on the anodes’ and separators’ mechanical properties, which had a lower mechanical strength and stiffness under tension. Additionally, quasi-static cylindrical indentation and three-point bending tests were performed to investigate aging effects on cell level at varying state of charge (SOC). Aged cells with 0% SOC showed a right-shifted force–displacement curve and a 29% lower maximum force compared to fresh cells. Fully charged, aged cells reached a similar maximum force to fresh cells, but faster temperature increase and higher temperature peaks after internal short circuit. Inductively coupled plasma optical emission spectrometry analyses confirmed an increased lithium content on the anode surface, which is indicated in literature as a reason for the increased exothermic reaction of the aged cells. The results indicate a higher safety risk for the aged investigated pouch cells under mechanical loads based on their changed mechanical properties and thermal runaway behavior.https://www.mdpi.com/1996-1073/15/3/847lithium-ion batteryelectrical aginglithium platingmechanical properties changequasi-static indentationcrash safety
spellingShingle Marvin Sprenger
Norbert Dölle
Florian Schauwecker
Marco Raffler
Christian Ellersdorfer
Wolfgang Sinz
Multiscale Analysis and Safety Assessment of Fresh and Electrical Aged Lithium-Ion Pouch Cells Focusing on Mechanical Behavior
Energies
lithium-ion battery
electrical aging
lithium plating
mechanical properties change
quasi-static indentation
crash safety
title Multiscale Analysis and Safety Assessment of Fresh and Electrical Aged Lithium-Ion Pouch Cells Focusing on Mechanical Behavior
title_full Multiscale Analysis and Safety Assessment of Fresh and Electrical Aged Lithium-Ion Pouch Cells Focusing on Mechanical Behavior
title_fullStr Multiscale Analysis and Safety Assessment of Fresh and Electrical Aged Lithium-Ion Pouch Cells Focusing on Mechanical Behavior
title_full_unstemmed Multiscale Analysis and Safety Assessment of Fresh and Electrical Aged Lithium-Ion Pouch Cells Focusing on Mechanical Behavior
title_short Multiscale Analysis and Safety Assessment of Fresh and Electrical Aged Lithium-Ion Pouch Cells Focusing on Mechanical Behavior
title_sort multiscale analysis and safety assessment of fresh and electrical aged lithium ion pouch cells focusing on mechanical behavior
topic lithium-ion battery
electrical aging
lithium plating
mechanical properties change
quasi-static indentation
crash safety
url https://www.mdpi.com/1996-1073/15/3/847
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