An Energy Harvester with Temperature Threshold Triggered Cycling Generation for Thermal Event Autonomous Monitoring

Abstract

This paper proposes a temperature threshold triggered energy harvester for potential application of heat-event monitoring. The proposed structure comprises an electricity generation cantilever and a bimetallic cantilever that magnetically attract together. When the structure is heated to a pre-set temperature threshold, the heat absorption induced bimetallic effect of the bimetallic cantilever will cause sufficient bending of the generation cantilever to get rid of the magnetic attraction. The action triggers the freed generation cantilever into resonance to piezoelectrically generate electricity, and the heated bimetallic cantilever dissipates heat to the environment. With the heat dissipated, the bimetallic cantilever will be restored to attract with the generation cantilever again and the structure returns to the original state. Under continual heating, the temperature threshold triggered cycle is repeated to intermittently generate electric power. In this paper, the temperature threshold of the harvester is modeled, and the harvester prototype is fabricated and tested. The test results indicate that, with the temperature threshold of 71 °C, the harvesting prototype is tested to generate 1.14 V peak-to-peak voltage and 1.077 μW instantaneous power within one cycle. The thermal harvesting scheme shows application potential in heat event-driven autonomous monitoring.

Theoretical and Experimental Investigation of a Rotational Magnetic Couple Piezoelectric Energy Harvester

“…It is more convenient to monitor the patient's breathing status over a long time period. Han et al used beams made of alloy layers with different expansion coefficients [4]. After absorbing heat, the alloy beams deformed to counteract the magnetic force and caused the piezoelectric beam to vibrate.…”

Special Issue on Energy Harvesters and Self-Powered Sensors for Smart Electronics

“…Employing the optimal length and thickness, the derived energy harvester showed an increment of 371% and 1000% in output power and normalized power density, respectively. Han et al [6] developed a bimetallic-cantilever-triggered piezoelectric energy harvester for self-powered and automatic heat-event monitoring. If the temperature reaches a preset threshold, the bimetallic cantilever will detach from the piezoelectric energy harvester, causing the resonance and output generation of the piezoelectric energy harvester.…”