Processing influences of resin-based insulation materials for wireless power transfer applications

Due to the electrification of the whole mobility sector, the demand for new insulation materials and processes is constantly increasing. Beside the electric traction drives, new technologies such as inductive charging are becoming more and more important in electric vehicles. Especially for wireless power transfer, high-frequency litz wires are used to generate the required electromagnetic field. While semi-finished products and insulation systems are continuously developing, insulation processes like potting remain unchanged. The consequence is an inappropriate insulation of the coil structure resulting in increasing eddy current losses or breakdowns of the inductance. Additionally, high mechanical and thermal loads, occurring in a typical operation environment for electric vehicles, result in accelerated aging of the insulation material. This increases the challenges in the design and manufacturing of insulation systems for inductive power transfer devices. The aim of this work is to identify and evaluate all relevant process parameters for potting high-frequency litz wires with varying primary insulation systems. To ensure the required mechanical and electrical properties, a high degree of impregnation of the litz wires is targeted.