@inproceedings{oai:jaxa.repo.nii.ac.jp:00008019,
 author = {百留, 忠洋 and 中村, 昌彦 and 吉田, 弘 and 澤, 隆雄 and 石橋, 正二郎 and Hyakudome, Tadahiro and Nakamura, Masahiko and Yoshida, Hiroshi and Sawa, Takao and Ishibashi, Shojiro},
 book = {第27回宇宙エネルギーシンポジウム　平成19年度, The Twenty-seventh Space Energy Symposium},
 month = {May},
 note = {There are concerns about the impact that global warming will have on our environment, and which will inevitably result in expanding deserts and rising water levels. AUVs (Autonomous Underwater Vehicle) were considered and chosen, as the most suitable tool for conducting surveys concerning these global environmental problems. JAMSTEC has started building a long range cruising AUV. An AUV, named 'URASHIMA', was built in 1999, and sea trials have been held since 2000. URASHIMA dived to 3,518 meters depth in 2001. At the end of February 2005, URASHIMA was able to cruise autonomously and continuously for 317 kilometers, beyond its target range of 300 kilometers. This record is the longest one in the world PEFC (Polymer Electrolyte Fuel Cell) power system with Metal Hydrogen storage has been developed for expanding its cruising range. 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 Lithium-ion battery or silver-zinc battery for power source. However the case of long range 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. And it makes worse the maneuverability and energy efficient of the vehicle. So we plan to use fuel cell as power source for underwater vehicle. The fuel cell is a kind of electric generator using the chemical reaction of hydrogen and oxygen. It is able to generate electricity directly from chemical reaction without any combustion or intermediate steps. Among various fuel cell systems considered, PEFC system is most suitable for underwater vehicles. Because of the PEFC system generates electricity at total efficiency about 54 percent and at low temperature about 60 degrees centigrade. The other kinds of fuel cell system generate electricity at over 100 degrees centigrade. It is difficult to handle in an underwater vehicle and bas negative influence on other electrical devices installed in the pressure vessel. And though the fuel cell is a kind of electric generator, mechanical noise and vibration is very small because the system need not using turbine. In the case of using the acoustic telemetry or other acoustic devices, it is good in small noise circumstance. The PEFC system of the vehicle has two stacks of generator cells in series. As each stacks generates 2 kW electricity and total output is 4 kW. Hydrogen is stored by metal hydride for safety. Among various metal hydride considered, we choose AB5 type metal hydride. Because the material is easy handling and suitable to onboard using such that charging temperature is less than 15 degree centigrade, discharging temperature is over 45 degree centigrade and storage temperature is 20-25 degree centigrade. It can store the hydrogen without any cooling system under the sunshine. Storage capacity of the metal hydride is about 1.5 wt percent., 資料番号: AA0063965006},
 pages = {26--30},
 publisher = {宇宙航空研究開発機構宇宙科学研究本部, Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA/ISAS)},
 title = {深海探査機用水素貯蔵システムの開発状況},
 year = {2008}
}