Thin-film sensors for temperature monitoring in high-current transmission

Requirements for temperature monitoring in high-current systems

In high-current applications for electric mobility, reliable temperature monitoring is mandatory to prevent component damage and malfunctions during charging. The aim of the project was to develop a sensor system capable of measuring temperatures directly at the electrical contact points with high precision, high dielectric strength and low latency – even under current loads of several hundred amperes.

Sensor technology directly integrated on the contact partner

Fraunhofer IST developed a thin-film system optimized for electrical insulation directly on contact partners made of electrolytic copper. A chromium sensor layer was deposited onto an aluminum oxide insulation layer with high dielectric strength and structured using photolithographic processes. In total, six sensors enable high-resolution temperature measurements directly at the contact points. Additional protective layers provide electrical insulation and wear protection.

High-resolution measurement data for safe charging processes

The developed sensors were successfully tested at an equivalent test bench at Fraunhofer IVI under current loads ranging from 300 A to 600 A. The measurement data confirmed low latency and reliable detection of temperature development at the contact partners. Based on these results, the sensor technology is planned to be tested in MCS charging connectors under real operating conditions. In addition, modular thin-film sensors on foil inserts are being developed to transfer the technology to further high-current transmission applications.