Thermo-viscoelastic analysis of an inductive charging system included in an eRoads. Incit-ev project

Abstract

This paper presents work carried out in WP4 of the European project INCIT-EV, to develop a thermo-mechanical model, for simulating the performance of electrified roads using an inductive system for the charging of electric vehicles. The system consists of a charging unit, made of a box containing a litz coil, inserted into the road, at low depth under the surface, and sealed using a resin. In previous studies [1], several solutions for the insertion of this system in the road structure were evaluated, using experimental and numerical studies. The purpose of this paper is to highlight the potential of thermo-viscoelastic FEM structural simulations to predict the response of the electric road system (ERS) taking into account daily thermal variations, and heat released by the inductive charging system. Firstly, thermal laboratory tests were performed to evaluate the temperature variations due to the operation of the charging system, and compared with FEM simulations, in order to validate different modelling assumptions (material characteristics, boundary conditions). Then, transient thermo-mechanical simulations were performed, considering different materials for the coil block (polyethylene, or concrete), and for the sealing resin, in order to evaluate different possible designs of the charging elements. The variations of the deformations of the different structures, and of the strain and stress fields, during representative temperature cycles, were studied and compared. Differences in mechanical response obtained with different sealing resins (elastic or viscoelastic) and different coil block materials (polyethylene, and concrete) were analysed and compared.