Self-Powered Wearable Electrocardiography Using a Wearable Thermoelectric Power Generator

Abstract

A self-powered wearable electrocardiography (ECG) system is demonstrated. The ECG sensing circuit was fabricated on a flexible PCB and powered by a wearable thermoelectric generator (w-TEG) using body heat as the energy source. To allow the TEG to obtain a large temperature difference for high power generation and also be wearable, a polymer-based flexible heat sink (PHS) comprised of a superabsorbent polymer (SAP) and a fiber that promotes liquid evaporation was devised. Parametric studies on the PHS were conducted, and the structure of the w-TEG was also optimized for the PHS. The output power density from the w-TEG with the PHS was over 38 μW/cm2 for the first 10 min and over 13 μW/cm2 even after 22 consecutive hours of driving the circuits. This power level is high enough to continuously drive the wearable ECG system, including the sensors and the power management circuits.

Energy harvesting using thermoelectricity for IoT (Internet of Things) and E-skin sensors

“…Different from heat sinks with PCMs or micro-channels mentioned above, not much research has been done on flexible heat sinks as their demand has been low. There have been several works [26,72,94] which adopt a flexible heat sink on a thermoelectric generator for body heat harvesting. Although the performance of body heat harvesting has been enhanced with the existence of a flexible heat sink, those research have aimed more on the flexible thermoelectric system rather than flexible heat sink.…”

“…To operate a miniaturized accelerometer which requires 2.4 μW of power with a 1.6 mV voltage, a DC-DC converter with an efficiency of 50% is adopted to boost the voltage up to 2.2 V. A demonstrated thermoelectric system successfully operates the miniaturized accelerometer powered from body heat, as in figure 6(a). Kim et al[72] represent a self-powered wearable ECG system using a DC-DC converter, as infigure 6(b). The system consists of a DC-DC converter, VDD shifter and an ECG module.…”

“…Flexible thermoelectric system with a voltage converter and wireless sensor powered by body heat: (a) the system operating an accelerometer from human motion[71]. (b) Operation of self-powered wearable electrocardiography[72]. (a) Reprinted from[71], Copyright 2018, with permission from Elsevier.…”

“…All rights reserved. (b) Reprinted with permission from[72]. Copyright 2018 American Chemical Society.…”

UV‐Curable Silver Electrode for Screen‐Printed Thermoelectric Generator

“…Thermoelectricity, a phenomenon which enables the direct conversion of heat into electricity or vice versa, is attractive because it allows electricity to be generated from waste heat and provide environmentally friendly cooling. Given its many advantages, a large number of studies have been carried out to investigate a wide spectrum of applications in military, medical, industrial, and telecommunications fields . For example, to generate power from a heat source that has an arbitrary shaped surface, flexible thermoelectric generators (TEGs) have been developed and studied …”