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Title: | CHEMO-MECHANICAL MODELLING OF FRACTURE IN HETEROGENEOUS CATHODE FOR LITHIUM-ION BATTERY |
Authors: | Singh, Avtar |
Keywords: | Lithium-ion battery;Polycrystallinecathode;Non-equilibriumthermodynamics; Bulk andinterfaces;Stressinduceddiffusion;Chemo-mechanicalcohesive;Inter-granular fracture; Intra-granularfracture;Phasefieldfracture;Straingradientelasticity;Generalized differential quadrature. |
Issue Date: | Aug-2021 |
Publisher: | IIT Roorkee |
Abstract: | Next-generationcathodesforlithium-ionbatteries(LIB)arecomposedofthepolycrystalline microstructure havingmulti-layeredthinfilmarchitectureorthecompositeswithactiveand inactiveparticlesembeddedinthematrix.Duetoinherentheterogeneities,thesecathodes generate mechanicalstressessufficientenoughtocausetheinitiationandpropagationof numerous typesoffractures.Inparticular,theemergenceofinter-andintra-granularcracks as wellasparticle-matrixinterfacedebondinghindersthetransportoflithium-ionsandelectrons, resulting incapacityfading.Therefore,addressingthemechanicaldegradationofcathode along withgeometricalconfigurationandmicro-structuralfeaturesisofmajorconcerntowards achievingenhancedandsustainableelectrochemicalperformance.Consequently,wehave developedathermodynamicallyconsistentmulti-physicsframeworktounderstandthechemo- mechanical interplaytowardsfracturebehaviorofpolycrystallinemicrostructurealongwiththe substrate/matrix. Theproposedframeworkaccountsfortheplasticdeformationofthehost lattice andthesubstrate.Achemo-mechanicalcohesivezonemodel(CZM)isformulatedto simultaneously capturethedecohesionandtransportacrossgrainboundaries,whileclassical CZM isusedbetweenthecathode/substrateinterface.Usingthefiniteelementbasednumerical framework,weexaminethemechanicalfailureandattendantvoltageprofilesforvariousmicro- structural andelectrochemicalparameters(i.e.,grainsizeandchargerate). Moreover,theproposednumericalmodelisextendedtounderstandtheroleofinter-and intra-granular fractureonthecoupledchemo-mechanicalbehaviorofpolycrystallinecathode. In thatcontext,thermodynamicsbasedcoupledchemo-mechanicalmodelisdevelopedto investigatetheevolutionofcomplexcrackpropagationandemergentvoltageprofilesfor polycrystalline cathodeparticleembeddedinthematrix.Aregularphase-fieldfractureparameter is introducedtocapturetheinter-andintra-granularcrackpropagationtogetherwiththeparticle- matrix interfacedebondingintheelectrode;thereby,thecoupledgoverningequationsarederived. Twodiffusedinterfacephase-fielddescriptorsareutilizedtodescribethegrainboundariesand particle-matrix interfaces.Subsequently,thedifferentfractureenergiesofthegrains,grain boundaries andparticle-matrixinterfacesareincorporated.Usingthefiniteelementbased numerical framework,theinteractionsbetweenthechemo-mechanicalbehaviorandattendant fracture mechanismsareaddressedtowardstheemergentelectrochemicalresponses.Various parametric studiesareperformedtoinvestigatetheeffectofgrainsizes,chargerates,and elastic modulusofthematrixontheoccurrenceofmultiplefracturemechanismswithinthe polycrystalline cathode. |
URI: | http://localhost:8081/jspui/handle/123456789/18037 |
Research Supervisor/ Guide: | Pal, Siladitya |
metadata.dc.type: | Thesis |
Appears in Collections: | DOCTORAL THESES (MIED) |
Files in This Item:
File | Description | Size | Format | |
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AVTAR SINGH 16920001.pdf | 57.72 MB | Adobe PDF | View/Open |
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