Mechanical design and layout of an alkaline fuel cell for an Autonomous Underwater Vehicle.

ENDURUNS is a European R&D project that consists in developing and demonstrating a long endurance sea surveying Autonomous Underwater Vehicle (AUV), powered by a hydrogen fuel cell, to perform seabed mapping, geological studies, surveillance, ocean search missions, mineral and mining exploration. The thesis was developed in the framework of this project in the company HYSYTECH. It is focused on the mechanical design of the fuel cell, figuring out challenges such as the design of the stack to fit a limited space, the heating and cooling process of some components in a sealed environment, setting up the system to guarantee neutral buoyancy and a stable barycenter, and finally, assuring the capability of the system to deal with the high pressures and the demanding seawater environment. Each challenge is solved using an analytical approach and software modeling, obtaining a conceptual power bank of 300W composed of a stack of 15 cells, able to work in ocean depths up to 800 m and neutral buoyancy in seawater. These results demonstrate the feasibility of a powertrain based on hydrogen fuel cells that allow an increased amount of energy stored onboard in comparison with conventional battery-powered AUVs.