A 3D Mesoscale Model of the Collector-Electrode Interface in Li-Ion Batteries

Abstract

To gain insight into the collector-electrode interface in Li-ion batteries, a mesoscale model resolved at the particle scale in a representative volume element domain was developed. The underlying microstructure was first generated using a random packing and a dynamic collision algorithm. A finite element stress analysis was then used to calculate the deformations which are induced by Li-ion concentrations. The collector-electrode mechanical interaction was modeled using an adhesive contact law which was derived from the atomistic Lennard-Jones energy potential considering Van der Waals attractions. A finite element electrical analysis followed to calculate the collector contact resistance considering quantum tunneling currents. As a model application, we elaborated the role of the electrode microstructure by evaluating the damage and contact resistances for 8 various LiFePO 4 based cathodes. We found that optimum interfaces would be achieved using a rough collector, low porosity, small particle sizes with disk like shapes and conductive additives in the interstitial sites. Pressure application was also beneficial. The developed model could be used either separately prior to commonly used porous electrode electrochemical models which require the collector-contact resistance as a parameter, or coupled in a 3D mesoscale electrochemical analysis so that a mechanical-electrochemical interaction would be considered.

Multiscale Morphological and Electrical Characterization of Charge Transport Limitations to the Power Performance of Positive Electrode Blends for Lithium‐Ion Batteries

“…This parameter is the areal density of contacts at the collector/electrode interface, Σ. The contact resistance is given as R C = R cr + R f , where R cr is the constriction resistance and R f is the resistance of the oxide film present at the extreme surface of the aluminum foil . R f is not expected to vary with the electrode composition.…”

X‐Ray Tomography of Porous, Transition Metal Oxide Based Lithium Ion Battery Electrodes

“…Three‐dimensional electrode simulations have the potential to overcome the inherent limitations posed by 1D and 2D models; however, electrode geometries used in 3D simulations are most often computer‐generated and thus their representation of real porous electrodes is questionable 5, 8, 10, 11. Goldin et al simulated highly symmetric arrangements of mono‐disperse spheres, Wang et al used a collision algorithm to simulate random packing and Awarke et al modeled compression of spheroid particles featuring a distribution of particle sizes 9, 12, 13…”

Redox reactions with empirical potentials: Atomistic battery discharge simulations

“…Those include, but are not limited to, ionic and electronic conductivities, specific surface areas, tortuosities, porosia) Electronic mail: w.dapp@fz-juelich.de b) Electronic mail: martin.mueser@mx.uni-saarland.de ties, activity coefficients, transference numbers, concentrations, diffusion coefficients, current densities, electrochemical potential, reaction rate constants, solid electrolyte interface transport processes, contact resistances between active material and current collector, and mechanical properties such as strain tensors, elastic moduli or fracture strengths. 8,17,[19][20][21] Unfortunately, this parameterizability which makes the approach suitable to describe real batteries also limits its general predictive power, especially on the nanoscale.…”