A technology developed by the Massachusetts Institute of Technology (MIT) helps unmanned submarines perform better. The so-called Open Water Power uses an alloy aluminium-based power system for this purpose.
Alloy
Many unmanned underwater vehicles (UUVs is the English acronym) use lithium batteries. But these have some drawbacks. For instance, they are flammable so they usually cannot be transported by air. In addition, their energy density is limited; expensive service ships are often needed to recharge the batteries. In addition, the batteries have to be encapsulated in metal pressure vessels, which also costs a lot of money.
The OWP power system, based on years of research, is safer, cheaper than lithium batteries and lasts longer, according to its makers. It consists of alloyed aluminium, a cathode fitted with a combination of elements (notably nickel) and an alkaline and an alkaline electrolyte placed between the electrodes.
Water in battery
When a UUV equipped with the power system is placed in the ocean, seawater is drawn into the battery which is split with the cathode into hydroxide anions and hydrogen gas. The anions interact with the aluminium anode, creating aluminium hydroxide and releasing electrons. These electrons return to the cathode, releasing energy in the meantime. Then the cycle starts again. Both the aluminium hydroxide and hydrogen gas are rejected as non-hazardous waste.
Components are activated only when flooded with water. Once the aluminium anode corrodes, it can be replaced at low cost. The power system can be thought of as a kind of underwater engine, where chemical reactions are created by the water, rather than by air as is the case with car engines.
Oil exploration
The power system has several applications: it can make UUVs dive deeper and longer. They can then inspect shipwrecks on the bottom, map the bottom and conduct other research. They can also be used in military applications and for offshore oil exploration. With OWP, a submarine can cover a distance 10 times longer than normal and thus check many more pipelines.
"Anything one wants to do or explore underwater should become a lot easier with this," states Salmon McKay, the co-founder of OpenWater Power. "We are ready to conquer the oceans."
By: Kelly Bakker
Source: MIT
