Piezo-based energy harvesting within medical implants: Page 2 of 3

April 25, 2019 //By Bill Schweber
energy harvesting
Researchers developed a prototype energy-harvesting transducer for medical implants, such as pacemakers, using normal motion of the heart-related blood vessels to generate critical power.

Fig. 1: Shown is the concept of piezoelectric
thin-film energy harvester for an implantable
cardioverter defibrillator and a flexible porous
PVDF-TrFE dual-cantilever energy harvester
on the AICD lead (A). Image from video analysis
of a chronically implanted pacemaker lead from
a dog (B). A dual-cantilever energy harvester within
a soft tube on the pacemaker AICD lead (C).
(Source: Thayer School of Engineering at
Dartmouth College).

To build the harvester transducer, the researchers used a combination of thin-film energy-conversion materials with a minimally invasive mechanical approach in a modified pacemaker design. They harnessed the kinetic energy of the lead wire that’s attached to a beating heart, and then converted it into electricity to continually charge the batteries – see figure 1. The power-generating material, a specialized polymer piezoelectric film called polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE), is designed with porous structures and then built into either an array of small beams or a flexible cantilever.

The team created a dual-cantilever structure that wraps around the pacemaker’s lead, with the structure’s two free ends available for connection and subsequent energy collection – see figure 2.

Fig. 2: Illustrated are a schematic of the porous
piezoelectric-energy harvester (A); flexible porous
PVDF-TrFE thin film (B); and scanning electron microscope
image of the cross-section of the thin film (C). (Source:
Thayer School of Engineering at Dartmouth College).

The maximum output was 0.5V at 43nA at 1Hz, a little over 20nW. By adding a small proof mass of 31.6 mg on the tip of the dual-cantilever tip, the power output increased by a little over 80% since the added mass enabled a larger bending curvature, resulting in higher electrical output from the harvester.

Vous êtes certain ?

Si vous désactivez les cookies, vous ne pouvez plus naviguer sur le site.

Vous allez être rediriger vers Google.