Implantable Thermoelectric Generator with High Aspect Ratio Thermolegs and Integrated Voltage Converter

Thermoelectric generators (TEGs) are becoming important for energy harvesting from body heat flow. Implantable TEGs utilize temperature gradients within the human body to provide electrical power, offering the potential to extend the lifespan of implantable medical devices (IMDs). This paper presents a TEG featuring high aspect ratio thermolegs, measuring up to
$0.5\times 0.5\times 4\ \text{mm}^{3}$
, enclosed within a compact polyetheretherketone (PEEK) housing, similar in size to a pacemaker. A novel fabrication approach enables seamless integration of a boost converter, resulting in a compact TEG with a 30 mm diameter. In simulated implantation scenarios, this TEG delivers
$53\ \mu \mathrm{W}$
of power at a voltage of 2.5 V under optimal load conditions, meeting the power requirements of IMDs such as pacemakers and neurostimulators. Additionally, the study validates the TEG's applicability through finite element model simulations, accounting for bio-heat effects within detailed high-quality human torso and head models.