Water Based Hydraulic System

Recent advances in battery technology open the possibility ofpressure-tolerant batteries, i.e., batteries that areintrinsically capable of withstanding ambient pressure in theopen ocean with negligible modification. Pressure-tolerantbatteries can increase an AUV's effective energy capacity by 50%to 100%, with no reduction in vehicle payload and no increase invehicle size. To get a corresponding increase in capacitythrough improvements in electrochemistry or cell manufacturingwould require investing many millions of dollars over many years,with no guarantee of success. In our Phase I effort we performedthe first systematic testing of appropriate cells under deepocean ambient pressure. Our results are promising. COTS cellsunderwent many electrical cycles at high rates (nominally C/2)while under isobaric conditions of over 6,700 psi, with noevidence of pressure-induced failures in either set of cells.Thus, there exist today COTS cells that can be used to build ahigh-capacity pressure-tolerant battery pack for Navy vehicles.For our Phase II effort we propose to engineer a pressure-tolerant battery pack based on the current state-of-the-art COTScells. Furthermore, the pack will be designed to allow it toreadily accept improved cells as they become commerciallyavailable