Understanding Electrolyte Filling of Lithium-Ion Battery Electrodes on the Pore Scale Using the Lattice Boltzmann Method

TL;DR

This study uses the lattice Boltzmann method to simulate electrolyte filling in lithium-ion battery electrodes at the pore scale, revealing how structural and chemical properties influence filling efficiency and residual gas entrapment, which affect battery performance.

Contribution

It introduces a computational pore-scale simulation approach for electrolyte filling in lithium-ion batteries, analyzing effects of structural and chemical properties on filling dynamics and residual gas entrapment.

Findings

Structural and chemical properties significantly influence electrolyte saturation.

Optimized filling conditions can improve battery performance.

Residual gas entrapment impacts electrolyte saturation and battery efficiency.

Abstract

Electrolyte filling is a time-critical step during battery manufacturing that also affects the battery performance. The underlying physical phenomena during filling mainly occur on the pore scale and are hard to study experimentally. In this paper, a computational approach, i.e.\ the lattice Boltzmann method, is used to study the filling process and corresponding pore-scale phenomena in 3D lithium-ion battery cathodes. The electrolyte flow through the nanoporous binder is simulated using a homogenization approach. Besides the process time, the influence of structural and physico-chemical properties is investigated. Those are the particle size, the binder distribution, and the volume fraction and wetting behavior of active material and binder. Optimized filling conditions are discussed by capillary pressure-saturation relationships. It is shown how the aforementioned influencing factors affect the electrolyte saturation. Moreover, the amount of the entrapped residual gas phase and the corresponding size distribution of the gas agglomerates are analyzed in detail. Both factors are shown to have a strong impact on mechanisms that can adversely affect the battery performance. The results obtained here indicate how the filling process, the final electrolyte saturation, and potentially also the battery performance can be optimized by adapting process parameters and the electrode and electrolyte design.