After a certain distance or time of travel, unmanned underwater vehicles (UUVs) must return to a base station to refuel or regain energy before continuing. UUVs could benefit from a self-contained energy source. Microbial fuel cells (MFCs) have been shown to power low-power undersea electronics such as modems and hydrophones. Through the use of electrodes, MFCs harness free electrons released from metabolizing microbes naturally found in ocean sediment. By integrating a bottom-resting MFC into a low-power UUV such as a glider, a UUV could sleep or rest in a remote area while recharging and extend its travel time.
The invention is essentially a self-propelled MFC. The MFC consists of an upper cathode and a lower anode, both of which are depth-sensitive and flexible. This allows the MFC to adjust between locomotion mode and bottom-resting mode. In locomotion mode, the MFC takes a nonplanar streamlined shape, protecting the anode in an enclosure. In bottom-contact mode, the enclosure opens and the anode becomes partially exposed to sea floor sediment to collect microbes and their free electrons. Having a planar orientation, with the ability to expose and conceal the anode, prevents the need for burying the anode when collecting microbes. Incorporation of nutrients into the design attracts and sustains microbe colonies within the cell. Impregnating the fuel cell with nutrients to sustain a thriving colony could ensure energy collection, even after the device has left a microbial rich environment. This technology may find application in UUVs, pop-up buoys, or low-power underwater equipment such as sensors or communication nodes.
- Comprises a green, sustainable energy source
- Adds mobility to MFCs and enables longer missions
- Potential for collaboration with Navy researchers
- Patent No., 8,916,299 available for license