It has long been known that batteries can be pressure compensated, i.e., modified to operate at depth [e.g., Work, 1968]. Unfortunately, these modifications bring along severe restrictions on vehicle handling as well as increased maintenance requirements, neither of which is acceptable for the new generation of small, low-cost, AUVs. Recent advances in polymer- electrolyte and all-solid-electrolyte lithium ion cells open the possibility of pressure-tolerant batteries, i.e., batteries that are intrinsically capable of withstanding the pressure with negligible modification. In this proposal we will demonstrate how such pressure-tolerant batteries can increase an AUV's energy capacity by 50% or more, with no reduction in vehicle payload and no increase in vehicle size. To get a corresponding increase in capacity through better electrochemistry or cell manufacturing would require many millions of dollars and many years of R&D effort, with no guarantee of success. For this Phase I effort we propose to perform the key tests required to demonstrate the feasibility of such pressure-tolerant batteries.
Benefits: This work will result in significant increases in the effective energy density of underwater battery packs. Such systems will power AUVs in scientific and military applications, as well as the critical off-shore oil and sub-sea telecommunications industries. Our market study show that, by 2005, AUV applications alone will constitute a multi-million dollar market for these batteries. In addition, the prospects for non-AUV uses are at least as promising.
Keywords: Autonomous Underwater Vehicles, Solid Electrolyte, Lithium Polymer, Pressure Tolerant, Pressure Compensation, Marine Power, AUV, battery
