A Thermal Energy Harvester Based on Bistable SMA Microactuation

Konferenz: ACTUATOR 2022 - International Conference and Exhibition on New Actuator Systems and Applications
29.06.2022 - 30.06.2022 in Mannheim

Tagungsband: GMM-Fb. 101: ACTUATOR 2022

Seiten: 4Sprache: EnglischTyp: PDF

Autoren:
Chen, Xi; Kohl, Manfred (Institute of Microstructure Technology, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany)
Bumke, Lars; Quandt, Eckhard (Institute for Materials Science, Kiel University (CAU), Kiel, Germany)

Inhalt:
We present the design, fabrication, and characterization of a miniature-scale thermal energy harvester based on bistable shape memory alloy (SMA) microactuation. This device consists of two free-standing Ti53.9Ni30.4Cu15.7 bridge structures with curved memory shape that are coupled by a spacer with a pick-up coil. The device undergoes a periodic oscillatory motion between two stable equilibrium positions, when placed in between two heat sources. An analytical model is implemented to simulate and optimize the force-displacement characteristics. The inhomogeneous field of a miniature permanent magnet induces a voltage in the pick-up coil. The resulting power output is investigated as a function of bridge geometry, heat source temperature and load resistance of the energy harvesting circuit. For a spacing between SMA bridges of 5 mm, the output voltage reaches 48 mV at heat source temperature of 160 °C corresponding to a maximum output power of 4.5 muW.