Turbulence-enhanced flexible thermoelectric generator with perforated fins and copper-encapsulated polyimide for high-performance body heat harvesting

Flexible thermoelectric generators are promising candidates for powering low-consumption wearable electronics via body heat harvesting; however, their performance is often limited by inadequate convective heat dissipation and inefficient thermal-electrical coupling. These limitations lead to reduced temperature gradients across the thermoelectric legs, which are directly related to the electrical power output of the device.This study proposes a turbulence-enhanced flexible thermoelectric generator integrated with copper-encapsulated polyimide substrates and perforated T-shaped fins to address these issues. A comprehensive multiphysics model was developed and validated against experimental data to investigate the fluid flow characteristics, temperature distributions, electric potential profiles, and electrical power output performance. Key design parameters, including T-shaped fin heads, circular perforations, and copper-encapsulated polyimide substrates, were systematically tailored to enhance turbulent mixing and convective heat transfer, sustaining a significant temperature gradient of 7.3 K across p-type (Bi_0.4Sb_1.6Te₃) and n-type (Bi_1.7Te_3.7Se_0.3) thermoelectric legs.At a temperature difference of 10.5 K, the turbulence-enhanced flexible thermoelectric generator achieved a power density of 325.216 μWcm−2 within a compact active area of 1.3456 cm2, representing a 57.95 % improvement over state-of-the-art designs. The device exhibited stable performance across load resistances (0.118-0.89 Ω) and hot-side temperatures (306.15-312.15 K), with a peak power output of 437.61 μW under the matched load condition.This study demonstrates a significant advancement toward high-performance, compact, flexible body heat harvesters and offers a promising energy supply solution for small-scale wearable electronics with low power demands.