(398j) Electrochemical Systems Optimization Using Physics-Based Homogenization of the Microscopic Continuum Models

Electrochemical systems such as fuel cells, flow batteries, and electrochemical reactors are prevalent in industry, but few tools for their numerical design and optimization exist. Simulation of these systems spans length-scales from sub-micron to meter and often requires the solution of multiple coupled partial differential equations (e.g. mass transport, momentum transport, and electrostatics). Appropriate resolution of the typically porous, electroactive component domain is often computationally expensive, making shape and topology optimization at this scale especially difficult if not prohibitive. To accelerate and enable the design optimization of these systems, we employ physics-based homogenization of the governing microscopic, continuum transport equations. In this presentation, we briefly review the homogenization formulation for porous electrochemical systems and our numerical methodology for extracting effective properties. We then apply these techniques to develop an up-scaled representation for a flow battery electrode composed of an architected porous medium consisting of an iso-truss lattice. Through resolved computations on the microstructural unit cell, we parameterize its macroscopic response as a function of the unit cell porosity to generate the homogenized model. By applying the adjoint method, we calculate model sensitivities with respect to the spatially varying of unit cell porosities, enabling design optimization at the device scale. We conclude by applying our methodology to generate optimized architectures for scale-up of flow-through electrodes.

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.