Operating sensors and detectors in strategic bay and coastal environments is critically important, but powering these devices can be difficult. Not only do batteries have to be able to survive in water, they have to be resistant to damage from wave action, aquatic life, and increased corrosion that can result from salty conditions. FlexEl, LLC has developed thin, flexible batteries that use this challenging environment to their advantage.
FlexEl, LLC, a custom and flexible battery solutions company and beneficiary of NavAir funding, has developed a seawater battery, which operates with a metal anode, a highly efficient proprietary cathode, and uses seawater as the electrolyte. Termed a reserve battery, it has infinite shelf life, meaning it does not lose its stored energy when stored in a dry state. Nevertheless, when deployed in the sea, the cell activates within 1-2 seconds, providing electricity. FlexEl’s seawater batteries are safe in operation, environmentally benign, and contain exclusively nontoxic materials. They can be built either flexible or in various custom forms.
A team, consisting of FlexEl interns Holly Barra, Antony Grzesik, and Mustafa Shahnawaz, undergraduates at the University of Maryland College Park, advised by Dr. Daniel Lowy Sr. Scientist at FlexEl performed several on-site deployments at the CBL research pier. Their work benefitted from the support of Professor Tom Miller and his staff at Chesapeake Biological Laboratory.
Water in the vicinity of the pier has salinity approximately one third that of regular ocean water represented a challenge for operating these cells because of its lower conductivity. Therefore, the team tested the use of bay water at FlexEl’s laboratories and found technical solutions to overcome this challenge. Next, the team built scaled up reserve batteries, which were deployed successfully, supplying energy over several days. Each deployed cell contained mechanical and design improvements as compared to previous cell generations.
With their innovated, technological advances, these batteries would enable the U.S. Navy and researchers to power ocean observing equipment in bay areas. Such custom form reserve batteries can also power the personal locator of a smart lifejacket of a person who falls overboard, or supply energy to sediments and pollution sensors, and acoustic sensor networks. A specially designed FlexEl reserve battery can even extend the operational life of a flight data recorder five times!
Overall, FlexEl demonstrated the sustained operation of these seawater batteries in a real environment, meaning in the presence of continuous wave motion and aquatic life.
FlexEl’s reserve battery prior to deployment
