Machine learning-assisted design of flow fields for redox flow batteries

Mularczyk

et al. 2023

Preprint

At the core of redox flow reactors, the design of the flow field geometry –which distributes the liquid electrolyte through the porous electrodes– and the porous electrode microstructure –which provides surfaces for electrochemical reactions– determines the performance of the system. To date, these two components have been engineered in isolation and their interdependence, although critical, is largely overlooked. Here, we systematically investigate the interaction between state-of-the-art electrode microstructures (a paper and a cloth) and prevailing flow field geometries (flow through, serpentine and four variations of interdigitated). We employ a suite of microscopic, fluid dynamics, and electrochemical diagnostics to elucidate structure-property-performance relationships. We find that interdigitated flow fields in combination with paper electrodes –which features a uniform microstructure with unimodal pore size distribution– and flow-through configurations combined with cloth electrodes –which have a hierarchical microstructure with bimodal pore size distribution– provide the most favorable trade-off between hydraulic and electrochemical performance. Our analysis evidences the importance of carrying out the co-design of flow fields and electrode microstructures in tandem. We hope these results can help researchers and technology practitioners in the design of electrochemical cell for convection-enhanced electrochemical technologies.

Section: Performance Trade-offs -mentioning

confidence: 99%

Investigating the Coupled Influence of Flow Fields and Porous Electrodes on Redox Flow Battery Performance

Mularczyk

et al. 2023

Preprint

“…However, these studies have been developed numerically, and their findings have only been experimentally tested by few authors. Wan et al used manufacturing methods based on machining the channels on the graphite plates, 30 whereas Trogadas et al manufactured their lung-inspired flow fields for polymer electrolyte fuel cells using 3D printing via direct metal laser sintering, achieving the defined geometry with a resolution of 33 μm. 19 Previous research leveraged interdigitated flow fields as the base pattern for optimization studies.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Based on this work, Lin et al used a similar methodology to design 3D flow fields in all-vanadium RFBs with full three-dimensional geometry variation, which resulted in significantly reduced power losses by evolving 3D geometries from the standard interdigitated flow field to optimized patterns in the three spatial dimensions. In an alternative effort, Wan et al used machine learning methods to identify eight potential flow field designs which can achieve superior limiting currents (with an increase of 22%), resulting in improvements up to 11% of the battery energy efficiency compared with the serpentine flow field . In both the non-heuristic and heuristic studies, , the potential and relevance of fractal and hierarchical features in flow fields were identified and exploided.…”

Section: Introductionmentioning

confidence: 99%

Engineering Lung-Inspired Flow Field Geometries for Electrochemical Flow Cells with Stereolithography 3D Printing

Heijden

ACS Sustainable Chem. Eng.

et al. 2023

Electrochemical flow reactors are increasingly relevant platforms in emerging sustainable energy conversion and storage technologies. As a prominent example, redox flow batteries, a well-suited technology for large energy storage if the costs can be significantly reduced, leverage electrochemical reactors as power converting units. Within the reactor, the flow field geometry determines the electrolyte pumping power required, mass transport rates, and overall cell performance. However, current designs are inspired by fuel cell technologies but have not been engineered for redox flow battery applications, where liquid-phase electrochemistry is sustained. Here, we leverage stereolithography 3D printing to manufacture lung-inspired flow field geometries and compare their performance to conventional flow field designs. A versatile two-step process based on stereolithography 3D printing followed by a coating procedure to form a conductive structure is developed to manufacture lung-inspired flow field geometries. We employ a suite of fluid dynamics, electrochemical diagnostics, and finite element simulations to correlate the flow field geometry with performance in symmetric flow cells. The lung-inspired structural pattern is demonstrated to homogenize the reactant distribution in the porous electrode and to improve the electrolyte accessibility to the electrode reaction area. In addition, the results reveal that these novel flow field geometries can outperform conventional interdigitated flow field designs, as these patterns exhibit a more favorable electrical and pumping power balance, achieving superior current densities at lower pressure loss. Although at its nascent stage, additive manufacturing offers a versatile design space for manufacturing engineered flow field geometries for advanced flow reactors in emerging electrochemical energy storage technologies.

“…Based on this work, Lin et al used a similar methodology to design 3D flow fields in all-vanadium RFBs with full three-dimensional geometry variation [29], which resulted in significantly reduced power losses by evolving 3D geometries from the standard interdigitated flow field to optimized patterns in the three spatial dimensions. In an alternative effort, Wan et al used machine learning methods to identify eight potential flow field designs which can achieve superior limiting currents with an increase of 22% and improve up to 11% the battery energy efficiency compared with the serpentine flow field [30]. In both the non-heuristic and heuristic studies [19], [20], the potential and relevance of fractal and hierarchy features in flow fields was identified and leveraged.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Engineering Lung-inspired Flow Field Geometries for Redox Flow Batteries with Stereolithography 3D Printing

Heijden

et al. 2023

Preprint

Redox flow batteries are well suited for large-scale electrical energy storage, yet their deployment remains hampered by technical and economic challenges. Within the electrochemical cell, the flow field geometry determines the electrolyte pumping power required, mass transport rates, and overall cell performance. However, current designs are inspired on fuel cell technologies but have not been engineered for redox flow battery applications where liquid-phase electrochemistry is sustained. Here, we leverage stereolithography 3D printing to manufacture lung-inspired flow field geometries and compare their performance to conventional flow field designs. A versatile two-step process based on stereolithography 3D printing followed by a coating procedure to form a conductive structure is developed to manufacture lung-inspired flow field geometries. We employ a suite of fluid dynamics, electrochemical diagnostics and finite element simulations to correlate the flow field geometry with performance in symmetric flow cells. The lung-inspired structural pattern is demonstrated to homogenize the reactant distribution in the porous electrode and to improve the electrolyte accessibility to the electrode reaction area. In addition, the results reveal that these novel flow field geometries can outperform traditional interdigitated flow field designs, as these patterns exhibit a more favorable electrical and pumping power balance, achieving superior current densities at lower pressure loss. Although at its nascent stage, additive manufacturing offers a versatile design space for manufacturing engineered flow field geometries for emerging redox flow batteries and other electrochemical energy storage technologies.