AUV NEWS: Saft lithium-ion battery system powers MOVE underwater vehicle
Posted on 09.02.2007 - 15:00 EST in AUV NEWS by Rons_ROV_Links
Saft lithium-ion battery system powers MOVE underwater vehicle during nine month deep sea exploration missions
A single charge of the Saft VLE rechargeable lithium-ion battery system can provide Marum's new deep sea exploration vehicle with up to nine months autonomous operation on the seabed.
A Saft lithium-ion battery system will power MOVE, an unmanned, autonomous deep sea exploration vehicle on missions lasting up to nine months, while it crawls the seabed at depths of several thousand metres to make continuous observations of processes at the ocean floor.
MOVE, which resembles the well-known Mars rovers, is one of the new generation of deep sea exploration vehicles under development at Marum, the University of Bremen's centre of marine environmental research and NIOZ, the Netherlands Institute for Sea Research. It is designed to serve as a mobile platform for various scientific instruments and experiments and has a maximum speed of 5 cm/s and a range of one km. An acoustic link to the surface is used to interrogate the vehicle and retrieve status information, scientific data and video and still images from the onboard camera.
Dr Christoph Waldmann, Marum's project manager for MOVE, said: "We face many of the same technological challenges encountered in space exploration. There are similar constraints regarding energy supply, communication bandwidth and controllability of the deployed systems. We decided to use a Saft lithium-ion battery system in the MOVE vehicle because it offered the ideal combination of high energy content, long-life, reliability and low self-discharge. This will enable us to deploy the vehicle on missions of up to nine months, to make repeated long term observations on the ocean floor without needing to recover the vehicle to recharge or change the battery pack." Integrated modular battery system
Saft has developed a special, modular integrated battery system for MOVE, based on VLE lithium-ion cells. These cells were originally developed for hybrid and electric vehicle applications to pack as much power as possible into a lightweight and space efficient package.
The MOVE battery modules comprise three parallel strings of seven VLE 45 Ah cells, providing a nominal 24 V and 135 Ah capacity, mounted in a tube to withstand deepwater pressures, and complete with an electronic control management system for the monitoring of charge and discharge voltages and cell temperatures. Four modules have been manufactured, and these can be mounted on the vehicle andconnected in parallel to provide the appropriate battery duration for each seabed mission, up to a total capacity of 540 Ah and 13.2 kWh. Deep water tests
MOVE has successfully completed sea trials in the Skagerrak, the deep water strait between Norway and the southwest coast of Sweden, at depths down to 650 m. It is now moving on to carry out its first scientific missions in shallow water regions of the North and Baltic Sea. About Saft
Saft (Euronext: Saft) is a world specialist in the design and manufacture of high-tech batteries for industry. Saft batteries are used in high performance applications such as industrial infrastructure and processes, transportation, space and defence. Saft is the world's leading manufacturer of nickel-cadmium batteries for industrial applications and of primary lithium batteries for a wide range of end markets. The group is also the European leader for specialised advanced technologies for the defence and space industries. With approximately 4,000 employees worldwide, Saft is present in 17 countries. Its 16 manufacturing sites and extensive sales network enable the group to serve its customers worldwide."