Development of fuel cell system for underwater power source

Research for the global warming, submarine earthquake or any ocean environmental fluctuation needs huge range observation. In order to gather various seawater data efficiently, Autonomous Underwater Vehicle (AUV) is very useful. Because the vehicle is able to cruise without tether cable joined to support vessel, and gather data and samples automatically. The development of the power source is one of important key technologies for battery drive underwater vehicle. Usually, many underwater vehicle used rechargeable battery such that silver-zinc battery for power source. However the case of cruising type AUV, it needs many electric power supplies in proportion to cruising distance. To extend cruising range, the battery must become heavier and lager. So we plan to replace Lithium-ion battery with fuel cell because of its high energy efficiency. In 2007, we started the conceptual design of a demonstration long-cruising-range autonomous underwater vehicle to cruise 3000 kilometers, getting to develop main devices including a fuel cell power system. The second generation fuel cell system must achieve the system efficiency of over 60%, downsizing compared with the first one, reducing consumption power on the auxiliaries, large endurance up to 600 hours. We had developed a second generation fuel cell system named HEML (High efficiency Multi-Less) fuel cell system which is characterized by a lack of gas recirculation blowers and humidifiers and reducing hydrogen leak (leak-less).