Paris, April 25th, 2007 – Saft has been awarded a contract by GESMA (Groupe d’Etudes Sous Marines de l’Atlantique) to develop a rechargeable lithium-ion (Li-ion) battery system that will notably boost the performances and payload capacity of the experimental platform Redermor (Unmanned Underwater Vehicle). The new Li-ion battery system will provide Redermor with up to five hours of autonomous power for its electric thrusters and onboard electronics. Packed in a compact, maintenance-free module, this battery system is just half the size of the previous one.
GESMA developed the Redermor UUV in the 1990s as an experimental platform used for evaluation of data acquisition and acoustic communications technologies for detecting and identifying underwater mines. Redermor is now operated as a fully autonomous free-swimming vehicle, it is six metres long, about one metre diameter and weights between 2.7 to 3.2 tonnes, according to the specific version. Eight electric thrusters allow Redermor to be very manoeuvrable and to travel at speeds of up to 10 knots at depths down to 200 m. It is also designed to carry large payloads (about one tonne and one cubic metre) such as high resolution sonar and large range of sensors.
Required power is drawn from a 260 V onboard battery. Within the designing process of the new version (Redermor-3), GESMA has chosen the Saft’s Li-ion technology in order to drastically reduce the size of the battery for the same performances as the current battery system and also to have an easy to operate and maintenance-free subsystem. The reduced size will enable the company to have additional equipment or to add another high power battery pack to literally double its endurance.
Custom designed Li-ion module
The Redermor-3 battery system is based on Saft’s VL45E Li-ion cells originally developed for hybrid and electric vehicle applications to pack maximum energy into a lightweight and space efficient package. With no maintenance, the battery system has a low auto discharge and offers an excellent reliability through its long operational lifetime. Saft will integrate these cells into a custom built module, designed to make the best possible usage of the limited dedicated space. The battery pack also include an electronic control management system for the monitoring of charge and discharge voltages and cell temperatures. The battery system is scheduled for delivery to GESMA in September 2007.