Life-saving medical implants like pacemakers and defibrillators face a big drawback: their batteries eventually run out. So every few years, patients need surgery to have the batteries replaced.

Now a company in New York state is planning to tackle the problem by providing patients with an implantable power source that recharges their implant’s batteries using electricity generated by the patient’s own body heat.

By continuously recharging the batteries, it saves the patient from frequent surgery. In some low power devices, it could even replace the batteries altogether, making such operations unnecessary.

The “biothermal battery” under development by Biophan Technologies of West Henrietta, will generate electricity using arrays of thousands of thermoelectric generators built into an implantable chip. These generators exploit the well-known thermocouple effect, in which a small voltage is generated when two of the junctions between two dissimilar materials are kept at different temperatures.

More here.