Energy harvesting
Scientists of Karlsruhe Institute of Technology (KIT; Germany; www.kit.edu) have developed three-dimensional component architectures for thermoelectric generators (TEGs) based on novel, printable thermoelectric materials. The results are reported in npj Flexible Electronics and ACS Energy Letters.
TEGs directly convert thermal into electrical energy. “This technology enables operation of autonomous sensors for the internet of things (IoT) or in wearables, such as smart watches, fitness trackers or digital glasses without batteries,” says professor Uli Lemmer, head of the Light Technology Institute of KIT. In addition, they might be used for the recovery of waste heat in industry and heating systems or in the geothermal energy sector.
“Conventional TEGs have to be assembled from individual components using relatively complex manufacturing methods,” Lemmer says. “To avoid this, we studied novel printable materials and developed two innovative processes and inks based on organic, as well as on inorganic nanoparticles.” These processes and inks can be used to produce inexpensive, three-dimensional printed TEGs.
The first process uses screen printing to apply a 2-D pattern onto an ultrathin flexible substrate foil using thermoelectric printing inks. Then, a generator about the size of a sugar cube is folded by means of an origami technique. This method has been developed jointly by KIT researchers, the Heidelberg Innovation Lab, and a spinoff of KIT. The second process consists of printing a 3-D scaffold onto the surfaces of which the thermoelectric ink is applied. Work is underway to commercialize the printed thermoelectric system.