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TECHNOLOGY NEWS: ELECTRONICS

A thermoelectric generator from Nextreme can be embedded into implantable devices to provide localized temperature control for medical therapy.

A miniature, thin-film thermoelectric generator (TEG) converts heat directly into electricity. Providing power densities as high as 3 W/cm², the TEG’s capabilities exceed those of bulk materials, and it can have a form factor that is as much as 20× thinner than bulk-material alternatives, according to the manufacturer, Nextreme (Research Triangle Park, NC, USA).

The compact product can be embedded into such devices as probes, catheters, and surgical tools, where it provides precise localized heating or cooling to the applied area. Suited for waste-heat conversion applications, the TEG can be integrated into implantable devices and has potential for reducing the effects of seizures, as well as for pain management, cancer treatment, and drug-delivery applications. It can also maintain local temperature. The area affected by the TEG can range from 0.3 × 0.3 up to 20 × 20 mm². Operating in a steady or cyclical manner, the device offers microscale thermal control at specific contained regions of the body.

“In environments where a lot of heat is available, we have demonstrated power levels of up to 300 mW with devices that are not much bigger than a piece of confetti,” says Seri Lee, Nextreme chief technology officer. “And, in low-grade thermal environments, we have achieved microwatts of power—enough thermal energy conversion to power remote sensors and other distributed devices.”

TEG devices generate electricity via the Seebeck Effect, in which electricity is produced from a temperature differential applied across the device. The product has demonstrated output power levels of greater than 100 mW at a temperature difference of 70 K, and greater than 300 mW at a temperature difference of 120 K. With modules measuring 3.5 × 3.5 mm², the TEG has output power densities of an estimated 1–3 W/cm².