Suitability of aluminium copper silicon eutectic as a phase change material for thermal storage applications: Thermophysical properties and compatibility

Latent thermal storage in metals can overcome many issues related to the temporal or spatial intermittency of heat resources, particularly in the provision of heat in electric vehicles. Alloys that are energy dense and thermally conductive are most attractive for thermal storage applications. The eutectic alloy, Al-25% Cu-6% Si (wt%) has been identified as an optimal metallic phase change material melting in the temperature range 508 degrees C to 548 degrees C. Through differential scanning calorimetry, light flash analysis and long-term reaction experiments, the thermal and compatibility characteristics of this alloy are experimentally determined. Graphite and alumina are observed as compatible housing materials for the alloy after 2 weeks at 550 degrees C. Reaction depth and products at the interface with iron and stainless steel are identified with energy-dispersive X-ray spectroscopy and electron backscatter diffraction analysis. A volumetric energy density of 0.7764 +/- 0.0178 kWh/L was calculated for an operating range of 160 degrees C to 660 degrees C from the measured properties, suggesting the material is an excellent candidate for thermal storage in electric vehicles.