Use of metallic Phase Change Materials (mPCM) for heat storage in Electric and Hybrid Vehicles

Abstract

To overcome the disadvantage of electric heaters for heating the interior in electric- and hybrid vehicles, consuming electric energy out of the traction battery, a thermal energy storage (TES) filled with metallic Phase Change Material (mPCM) is proposed in this study. Out of the defined requirements to energy storage systems resulting from the application in electric vehicles, which are a thermal output of maximum 3,5 kW and a storage capacity of 1,9 kWh, a concept for implementation of the TES into the system of an electric vehicle is shown. The adjustment of the storages thermal output is implemented by adjustment of two fans, the one perfusing the storage, the other one soaking in cold air for mixing with the hot airstream out of the storage. For experimental investigation and proof of concept, a downsized functional demonstrator was built up and filled with the Phase Change Material AlSi12. The specific heat capacity of the material measured by Difference Scanning Calorimetry (DSC) is 1006 J/kgK in solid state and 1073 J/kgK in liquid state. The melting enthalpy is 511 kJ/kg. The measurement of the storage systems thermal output shows the high potential of mPCM enabling high heat transfer rates, due to their high thermal conductivities. A maximum thermal output of 1,3 kW (design point 1 kW) could be measured.