Understanding the Impact of Convective Transport on Intercalation Batteries Through Dimensional Analysis

Performance and cost requirements for emerging storage applications challenge existing battery technologies and call for substantial improvements in cell energy and rate capability. Convection batteries can reduce mass transport limitations commonly observed during high current operation or with thick electrodes. In prior proof-of-concept work, while convection was shown to improve cell performance, its effectiveness was limited in the select cases studied. To understand the feasibility of the convection battery more comprehensively, we develop a mathematical model to describe convection in a Li-ion cell and evaluate performance as a function of a broad range of cell dimensions, component properties, as well as electrochemical and flow operating conditions. Qualitatively, we find that electrolyte flow enhances accessible capacity for cells with large electrolyte diffusive transport resistance and low initial amounts of electrolyte salt by reducing spatial concentration gradients and, thus, allowing for efficient high current operation. Quantitatively, by leveraging dimensional analysis that lumps >10 physical and cell parameters into representative dimensionless groups, we describe the efficacy, trade-offs, and upper performance bounds of convection in an electrochemical cell. Our analyses suggest that this format has the potential to enable high-power energy-dense storage which, in turn, may offer new application spaces for existing and emerging intercalation chemistries.