Technology Research

MIT Develops Scheme for Energy Harvesting That Eliminates Need for Batteries

• By Dian Schaffhauser
• 02/18/10

Batteries are the bane of modern life, especially when they're located in an inaccessible location such as a biomedical monitoring system or the interior of an industrial flue or vent, making them tough to replace. Results from research at MIT may eventually eliminate the need for batteries in small electronic devices that need to work for long periods of time.

Researchers Anantha Chandrakasan and Yogesh Ramadass are developing "energy-scavenging systems" that exploit the differences in temperature between the body (or some other warm object) and the surrounding air to power sensors. The systems use the differences in temperature to produce tiny amounts--about 100 microwatts--of electrical power. That would be sufficient, the researchers said, for example, to power 24-hour-a-day monitoring of heart rate, blood sugar, or other biomedical data. This could be done through a simple device worn on an arm or a leg and energized just by the body's temperature, which would almost always be different from the surrounding air.

The scientists have created a control circuit that performs maximal transfer of the extracted energy to a storage capacitor. Currently, their experiments have resulted in a metal heat-sink device worn on an arm or leg and exposed to the ambient air. Next, they'll try to miniaturize the whole system.

The findings were recently presented at the International Solid State Circuits Conference in San Francisco. The research was funded by a seed grant from the MIT Energy Initiative.