Researchers Turn to Miniaturized, Easily-Manufactured Thermoelectric Generators for Future IoT Nodes
While initial prototypes harvest limited energy, the team is hopeful optimization work will turn these generators into IoT powerhouses.
A team of researchers from Japan's National Institute for Materials Science (NIMS), National Institute of Advanced Industrial Science and Technology (AIST), and the University of Tsukuba have come up with a way to miniaturize a thermoelectric generator — such, they say, that it could prove ideal for powering devices on the Internet of Things (IoT).
"The direct conversion of heat into electricity via thermoelectric materials is a promising energy harvesting technology," the researchers claim. "In particular, as an ideal microscale onboard power source for self-powered electronics, possible miniaturized thermoelectric devices are attracting attention for applications involving the effective use of the thermal energy generated from unusually high heat density during the operation of electronic devices and systems."
The problem: thermoelectric generators small enough for integration into electronic devices typically harvest too little energy to be useful, while generators capable of harvesting useful amounts of energy are too bulky. Where the generator is both small enough and efficient enough to be of use, they are often too complex to mass manufacture.
"Almost all modern high-performance thermoelectric materials are incompatible with CMOS [Complementary Metal-Oxide Semiconductor] processes or MEMS [Microelectromechanical Systems] technologies," the team explains. "In this study, we focus on the development of miniaturized thermoelectric devices based on modern thermoelectric materials by using standard microfabrication techniques based on photolithography and dry-etching processes."
The result is a highly-reliable thermoelecrtric generator offering an output power of 0.6μW at 0.58V, equivalent to a output power density of 21mW/cm⁻² — still insufficient for practical applications, the team admits, but an ideal basis for an easily-manufactured energy harvesting system following future work on optimization.
"The successful demonstration of a microfabricated thin-film-based thermoelectric device paves the way toward novel thermoelectric applications for self-powered Internet of Things devices and systems," the researchers conclude, "as well as applications involving the effective use of the waste thermal energy generated from high heat density during the operation of electronic devices and systems."
The team's work has been published in the journal Materials Today Energy under open-access terms.