On Nonlinear Modelling of Structural Battery Composites
Licentiatavhandling, 2024
to simultaneously store electrochemical energy and carry mechanical load. A
conventional lithium-ion battery comprises a positive electrode, a separator,
and a negative electrode. The constituents are soaked in a liquid electrolyte,
allowing lithium-ion exchange between the electrodes while electrons travel
through an external circuit via current collectors. In structural batteries,
the negative electrode is replaced by multifunctional carbon fibres, enabling
the additional function as mechanical reinforcement. The liquid electrolyte
is replaced by a porous two-phase matrix material. The solid polymer phase
transfers mechanical loads between the carbon fibres, and the lithium ions
travel in the liquid phase, occupying the pores in the polymer matrix. Redox
reactions occur on the electrode/electrolyte interfaces. For instance, reduction
of lithium ions forms neutral lithium that diffuses inside the carbon fibres
in a charge process of a structural battery full cell. Lithium insertion is accompanied
by extensive carbon fibre expansion, which causes internal stresses
and affects the elastic moduli of the carbon fibres. In contrast, applying a
mechanical load to the lithiated carbon induces a response in the electric
potential.
In the first paper, we study the effect of the carbon fibre expansion on the
surrounding matrix material in a structural negative electrode. In particular,
we investigate the significance of adopting non-linear kinematics. In this way,
features such as the internal stress state, homogenized tangent stiffness, and
expansion of the homogenized negative electrode can be predicted.
The second paper concerns multiphysics modelling of a structural battery
full cell, that is, a LiFePO4 (lithium-iron-phosphate) based positive electrode
against a carbon fibre negative electrode. Specifically, we introduce non-linear
reaction kinetics to describe the redox reactions occurring on the electrode /
electrolyte interfaces. Moreover, we discuss coupled electro-chemo-mechanical
modelling of the positive electrode and the pertinent calibration towards experimental
findings.
Coupled problems
Computational Homogenization
Model calibration
Li-ion battery modelling
Multifunctional materials
Författare
Carl Larsson
Chalmers, Industri- och materialvetenskap, Material- och beräkningsmekanik
Effects of lithium insertion induced swelling of a structural battery negative electrode
Composites Science and Technology,; Vol. 244(2023)
Artikel i vetenskaplig tidskrift
Larsson C, Larsson F, Xu J, Runesson K, Asp L.E, An-Electro-Chemo-Mechanical Model for Analysis of Structural Battery Composite Full cells
Utveckling av strukturella batterier
United States Air Force (USAF) (Award # FA8655-21-1-7038), 2021-09-01 -- 2024-08-31.
Ämneskategorier
Teknisk mekanik
Reglerteknik
Kompositmaterial och -teknik
Thesis for the degree of licentiate of engineering - Department of Applied Mechanics, Chalmers University of Technology: IMS-2024-4
Utgivare
Chalmers
Virtual Development Lab (VDL)
Opponent: Ajit Panesar, Imperial College London, GB