Abstract
Structural batteries are multifunctional composites that combine load-bearing capacity with electro-chemical energy storage capability. The laminated architecture is considered in this paper, whereby restriction is made to a so called half-cell in order to focus on the main characteristics and provide a computational tool for future parameter studies. A thermodynamically consistent modelling approach is exploited for the relevant electro-chemo-mechanical system. We consider effects of lithium insertion in the carbon fibres, leading to insertion strains, while assuming transverse isotropy. Further, stress-assisted ionic transport is accounted for in addition to standard diffusion and migration. The relevant space-variational problems that result from time discretisation are established and evaluated in some detail. The proposed model framework is applied to a generic/idealized material representation to demonstrate its functionality and the importance of accounting for the electro-chemo-mechanical coupling effects. As a proof of concept, the numerical studies reveal that it is vital to account for two-way coupling in order to predict the multifunctional (i.e. combined electro-chemo-mechanical) performance of structural batteries.
Highlights
In recent years, there has been a growing interest in multifunctional materials which can enable pathways for energy efficient and sustainable transportation [1,2,3,4,5,6,7,8,9,10]
Electro-chemical cycling: Galvanostatic vs. potentiostatic control To demonstrate the characteristics of the two basic controls of electro-chemical cycling, the studied structural battery half-cell is discharged under galvanostatic conditions and potentiostatic conditions, while assuming the loading condition Load(iii)
For the galvanostatic control, the battery cell is discharged at a constant current I−(t) = Ipre, estimated as: Ipre = Cfmf, where carbon fibres (Cf) is the assumed specific capacity for the fibre and mf is the mass per unit length of the fibres
Summary
Keywords: Li-ion based structural batteries, multifunctional composites, electro-chemo-mechanical coupling, finite element analysis (FEA), multiphysics modelling Original Content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence.
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