Pressure-tolerant batteries promise improved performance for deep-dive underwater vehicles

A consortium led by UK industrial computing specialist Steatite has announced the successful completion of the first phase of a 24-month project to develop a pressure-tolerant lithium sulphur (Li-S) battery pack.

The firm claims that the technology could help to improve the endurance and speed of ‘deep-dive’ autonomous underwater vehicles (AUVs).

The technology could help increase the operational envelope of AUVs

The project, which is due for completion in October 2017, aims to exploit the potential of Li-S cell technology to surpass conventional lithium-ion (Li-ion) solutions, and will enhance the capabilities of the scientific and defence vehicles used in applications across the marine and maritime community, including subsea structures, ROVs, profilers, buoys and submersible systems.

AUVs are energy-limited, which constrains their operational envelope meaning that speeds are usually low (2-4 knots) and endurance can be limited.

By increasing the energy available within the vehicle, this operational envelope could be expanded, thereby raising both speed and range.

At the same time, as vehicles go deeper, the pressure vessels become excessively heavy and expensive and AUVs with internal batteries become limited by the fact that these batteries have to be recharged.

The Consortium – led by Steatite and funded by Innovate UK and the Defence Science and Technology Laboratory (Dstl) – aims to produce a pressure-tolerant battery pack that gets around these challenges.

During testing at the National Oceanography Centre (NOC) in Southampton the team demonstrated that Li-S cells can meet the demanding challenge of operating at depths up to 6000m. The project is now moving on to the battery development phase involving continued development of a pressure-tolerant multi-chemistry Battery Management System (BMS).