Thermomechanical properties of architected materials

Abstract

Lithium-ion batteries (LIB) in electronic vehicles (EVs) suffer a thermal hazard known as thermal runaway (TR). This phenomenon is produced when the internal temperature of the battery rises to a point where the separator between anode and cathode evaporates, initiating an unstoppable exothermic reaction culminating in fire and/or explosion of the EV. This effect is sought to be mitigated by the usage of forced convection mechanism or phase change materials. However, these cases only tackle the heat dissipation problem. In reality, in a traffic accident, a short circuit could be produced increasing the internal temperature of the battery and initiating TR. That’s why a multipurpose approach was given to this study. Porous structure offers lightweight materials with reduced properties. The focus of this study was to alter the orientation and amount of the unit cell (UC) to recover some of the properties of the base material. The rotation is focused on increasing the cross-sectional area of the structure while the amount of the UC is focused on increasing the volume fraction. With this setup, the impact of the area and volume were analyzed individually in a factorial analysis for the thermal conductivity and strain energy of the samples. After the best porous structure was obtained for its highest thermomechanical properties, composites with an onyx hybrid matrix and glass fiber reinforcement were used to manufacture a new porous structure—an architected material. The results showed that the simple cubic lattice at 45º angle and 2 UCs with a hybrid matrix (SLC4 w/ HM) produced the highest thermal conductivity while the addition of a reinforcement was not significant for the mechanical and thermomechanical analysis.