Wearable Thermoelectric Generator With Copper Foam as the Heat Sink for Body Heat Harvesting

Wearable thermoelectric generator (TEG) is an attractive technology to enable self-powered electronics and sensors for healthcare and the Internet of Things through its ability to convert body heat into electricity. However, the actual inner temperature gradient in the thermoelectric legs is relatively small when a TEG is worn on the body, which leads to a low voltage and power generation. To enhance the output performance, the structural design of a wearable TEG with copper foam as the heat sink is proposed. A thermal resistance model was developed to investigate the effects of using copper foam heat sink on the heat transfer and performance of the TEG. In addition, for comparison, the inner temperature gradients and open-circuit voltages of the TEGs with and without plate-fin heat sink were analyzed. Then, these different TEGs were fabricated and tested using an experimental setup. The results showed that TEGs with heat sinks could generate greater open-circuit voltage and output power values, while the TEG with copper-foam heat sink achieved the highest power-to-weight ratio. Finally, a wearable TEG with copper-foam heat sink was connected to a step-up circuit and worn on the wrist to power a miniaturized accelerometer for body motion detection. The results demonstrated that the wearable TEG with the copper-foam heat sink design provided a potential pathway for the realization of electronics powered by harvesting the human body heat.