North Carolina State University engineers have designed a flexible EGain material thermoelectric energy harvester. The potential to rival the effectiveness of existing power wearable electronic devices. Using body heat as the only source of energy.
Wearable devices used to monitor a variety of health and environmental measures are becoming increasingly popular. However, pale in comparison to rigid devices. Superior in their ability to convert body heat into usable energy.
We wanted to design a flexible thermoelectric harvester that does not compromise on the material quality of rigid devices. Provides similar or better efficiency said Mehmet Ozturk, a professor of electrical and computer engineering at NC State. Using rigid devices is not the best option when you consider a number of different factors. Superior contact resistance or skin contact with flexible devices. As well as the ergonomic and comfort considerations to the device wearer.
Liquid metal of gallium and indium EGaIn
Thermoelectric materials used in rigid devices in a flexible package, so that manufacturers wouldn’t need to develop new materials when creating flexible devices. the key challenges of a flexible harvester is to connect thermoelectric elements in series using reliable, low-resistivity interconnects. Liquid metal of gallium and indium – a common, non-toxic alloy called EGaIn to connect the thermoelectric legs. The electric resistance of connections very low, critical until the generated power is inversely proportional to the resistance Low resistance means more power.
Using liquid metal also adds self-healing function If connection broken, the liquid metal reconnects to make the device work efficiently again. Rigid devices are not able to heal themselves.
Future work will focus on improving the efficiencies of these flexible devices, by using materials and techniques to further eliminate parasitic resistances.