Thin film technology flexible thermoelectric generator and dedicated ASIC for energy harvesting applications

In this work we present a thermoelectric energy harvesting system consisting of a miniaturized and wearable flexible thermoelectric generator (TEG) and a dedicated ASIC, finalized to efficiently recover and manage energy from heat dispersed into the environment. The proposed TEG was realized on flexible Kapton substrate, which is particularly appreciated for its optimum properties of chemical and physical stability, permeability to atmospheric agents (humidity, oxygen) and thermal conductivity. Contrary to a conventional rigid substrate, like glass or silicon, a flexible one adds to the device lighter weight, increased robustness, freedom of shape, compactness, and low cost. Although the TEG was designed as "electronic garment" for wearable use in Ambient Assisted Living (AAL) applications, the device can be easily adapted to different contexts thanks to its flexibility and design that extend the application range to various sectors, from home automation and structural health monitoring to biotechnology. A Transfer Length Method (TLM) analysis was performed on three different multi-layer contact schemes in order to select the best solution to use for the deposition of both embedded thermometers to monitor the thermocouples junctions temperature and contact pads to electrically test single partitions of the array. A custom designed ASIC, based on step-up principle was coupled to the TEG in order to ensure a 1.2 V output and complete power management solution for wireless sensing and data acquisition.