On thermally managing lithium-ion battery cells by air-convection aspirated in tetrahedral lattice porous cold plates

Abstract

The faster charge/discharge of lithium-ion batteries that power unmanned aerial vehicles (or drones) increases heat emission substantially, thus requiring effective thermal management solutions. In this study, we present such a thermal solution for prismatic lithium-ion battery cells managed by “naturally aspirated air-convection” in tetrahedral lattice porous cold plates as a multi-functional application that requires a core element for simultaneous thermal and structural load bearing. To demonstrate the effectiveness of the solution, a series of steady-state numerical simulations and experiments were performed under specific thermal/flight conditions. Results showed that aspirated air-convection in multiple tetrahedral lattice porous cold plates, each sandwiched between two battery cells, enables the operating temperature of the battery cells to fall within a typical safety margin during forward flight. In comparison to empty cold plates as reference, an equivalent thermal performance was provided although higher pressure drop in the porous cold plates substantially reduces the flowrate of the aspirated convective flow than that in the reference cold plates. However, the porous cold plates could additionally mitigate mechanical fracture and structural degradation resulting in irreversible capacity loss due to repeatable thermal expansion/shrinkage during the charge and discharge. Thus, the tetrahedral porous cold plates may provide effective multi-functionality that is required for the cell-level thermal management of prismatic lithium-ion batteries.