Looking to address the problem, an engineering team from North Carolina State University says it has developed a flexible thermoelectric energy harvester with the potential to rival the effectiveness of existing solutions using body heat as the only source of energy.
“We wanted to design a flexible thermoelectric harvester that does not compromise on the material quality of rigid devices, yet which provides similar or better efficiency,” said Professor Mehmet Ozturk. “Using rigid devices is not the best option when you consider a number of different factors.”
According to Prof Ozturk, one of the key challenges of a flexible harvester is to connect thermoelectric elements in series using reliable, low-resistivity interconnects. “We use a liquid metal of gallium and indium – a common, non-toxic alloy called EGaIn – to connect the thermoelectric ‘legs’,” he said. “The electric resistance of these connections is very low, which is critical since the generated power is inversely proportional to the resistance.”
Using liquid metal is also said to support self healing – if a connection is broken, the liquid metal will reconnect to make the device work efficiently again.
