A high-output-voltage micro-thermoelectric generator having high-aspect-ratio structure

A high-output-voltage micro-thermoelectric generator (mu TEG) has been developed by fabricating thermocouples having a high aspect ratio (HAR) with a high integration density. They have been made by a novel and simple fabrication method, in which thermoelectric nanopowders are filled in a photosensitive glass mold by using aerosol deposition. It is followed by hot isostatic pressing to improve the thermoelectric property. This method has the possibility of increasing the aspect ratio of thermocouples drastically while increasing their toughness. We have fabricated thermocouples with an aspect ratio of 3.5 and a high integration density of 620 TCs cm(-2). Their Seebeck coefficient and electrical resistivity are 290 mu V K-1 and 1.5 m Omega cm, respectively, which make them as good as the thermocouples fabricated by hot pressing. By using the method, we have fabricated a mu TEG chip having an area of 25 mm(2) in which 56 thermocouples are arranged in an area of 9 mm(2). The mu TEG reaches a thermal resistance of 17.1 K W-1, output voltage efficiency of 0.16 V cm(-2) K-1 and output power efficiency of 9.3 mu W cm(-2) K-2. These HAR thermocouples have an advantage for energy harvesting from a human body because they can result in a high temperature difference because of their high thermal resistance.