Review of Autonomous Undersea Vehicle (AUV) Developments 
Batteries 
The NSB had the following comments regarding battery power systems [2]. 
"The science of electrochemical energy storage is fundamentally mature. The pace of development is 
relatively slow, but the need for safe and reliable electric power is so pervasive that there is a constant 
high level of research and development. New commercial battery products find their way onto the 
market, as historical shortcomings in the safety and stability of materials and chemical reactions are 
resolved. This was the case, for instance, in the recent development of the nickel metal hydride (NiMH) 
battery as a replacement for the environmentally unsound nickel cadmium (NiCd) battery. 
Technology development promises evolutionary progress in the realization and utility of the physical 
potential within the basic chemistries. Several long-term efforts in commercial and government 
establishments focus on improvement in shelf life, safety, volumetric and gravimetric energy values, and, 
in the case of secondary batteries, smart controls for charging efficiency and cycle lifetimes. 
Where weight is a major concern or the application calls for both long shelf and operating lives, lithium- 
based chemistries are a clear leader. Primary lithium batteries with 20-year shelf lives are in current use 
in smart mines and kinetic kill weapons. The U.S. Army has been a leader in the development of high- 
density, high-power, 6- to 12-V battery power systems for vehicles, pulsed-power weapons, remote power 
backup, and missile systems. The utility of high-power systems that are capable of operating in severe 
environments is driving further research on lithium battery safety issues such as handling and mitigation 
of volatile chemistry systems. 
Nickel-hydrogen has long been the preferred spaceborne secondary battery technology. Capable of high 
discharge rates and nearly infinite charge-discharge cycling, nothing currently matches its reliability. 
Underwater applications have been dominated by silver zinc (AgZn) systems. Some silver aluminum 
units are in use for lower power applications such as small torpedoes and the smaller offboard vehicles, 
but AgZn batteries are widely used for high-power applications. These can provide up to 100 kW over 15 
minutes and, together with advanced electric motors, can propel a torpedo at high speed.” 
Tables 2-5 provide additional details on power cells. 
Table 2. Primary Battery Cell Types with Promise as Prospective Power Sources 
Chemistry Cell W-h/kg Notes 
Volt 
Aluminum-Silver Dioxide 1.57 Pumped electrolyte; heat 
Al-Ag202 exchanger required 
Calcium-Thionyl 3:40 Increased tolerance to abuse 
Chloride over Li 
Ca-SOC12 
Calcium-Sulfuryl 322 Increased tolerance to abuse 
Chloride over Li 
Ca-SO2C12 
SOURCE: Compilation of data from Bis, R.F., J.A. Barnes, W.V. Zajac, P.B. Davis, and R.M. Murphy, 1986, Safety 
Characteristics of Lithium Primary and Secondary Battery Systems, NSWC TR 86-296. Navy Surface Weapons Center, Silver 
Spring, Md., July; and Bis, R.F., and R.M. Murphy, 1986, Safety Characteristics of Non-lithium Battery Systems, NSWC TR 
86-302 Rev. 1, Naval Surface Weapons Center, Silver Spring, Md., July. 
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