BATTERIES FOR GEOTHERMAL, OIL, AND GAS BOREHOLE SYSTEMS Sandia National Laboratories (Albuquerque, New Mexico) is developing novel battery technologies for providing power to down-hole drilling systems. Small, high temperature (150o to over 300oC) power sources are needed to meet the demands for powering newly emerging high-temperature electronics. New, high-temperature, battery-operated instruments have immediate application in geothermal, oil, and gas borehole equipment. With adequate power, data from sensors can be logged in real time and stored for later retrieval. Drilling systems can react immediately to down-hole conditions with electrically powered actuators. Several electrochemical technologies, such as sodium/sulfur and thermal batteries, are feasible for the extreme environments present in down-hole applications. While rechargeable technologies might be advantageous, non-rechargeable systems with a long enough run time are also practical. Sandia has been investigating the use of non-rechargeable thermal batteries using electrolytes that melt in the range of 150o to 300oC for these applications. Sandia Labs has been designing, developing, and producing thermal batteries for over 40 years as part of its responsibility for system engineering of nuclear weapons. Thermal batteries have been developed at Sandia with extremely long shelf lives (more than 30 years), high power densities and specific powers, and four 9s-plus reliability. Sandia has extensive battery development and fabrication facilities, world class expertise, and is an industry leader in the R&D of thermal batteries. Thermal batteries typically consist of the lithium-silicon/iron disulfide electrochemical couple with a conductive salt (molten at elevated temperature) as the electrolyte. A bipolar cell stack in a hermetically-welded container is used, and at room temperature, the batteries are inert. To activate the batteries, iron/potassium perchlorate pellets built into the stack are ignited and the battery heats up to operating temperature in milliseconds to several hundred milliseconds. Once hot, the electrolyte melts, and the battery begins delivering power. Typical weapon batteries operate between 400o and 550oC according to the use of specific electrolytes. However, recent research has focused on using lower-melting electrolytes. One halide electrolyte that melts at 228oC has been successfully scaled-up in 5- and 10-cell batteries and operated in simulated borehole environments. One ran over 21 h under a 125 mA load at a temperature of 250oC. Other, lower-melting point nitrate electrolytes are being screened for compatibility with various candidate anodes and cathodes. Several promising candidates for batteries operating at 150oC have been identified. Run-times of 24 h or more are possible with the advanced technologies being studied. Sandia is seeking collaborators to fully develop this technology for a wide range of commercial uses. Sandia wishes to partner with the battery, geothermal, or oil & gas industries. Possible collaborative mechanisms include licensing or cooperative development agreements. Preference will be given to organizations willing to co-fund development activities. For further information, please respond by mail or fax to Sheila Pounds by January 12, 2000 at: Sandia National Laboratories, MS 1380, P. O. Box 5800, Albuquerque, New Mexico 87185-1380. Fax: (505) 843-4163. Please indicate the date and title of this CBD notice and the type of partnering agreements your company would be most interested in entering into. E-MAIL: Sheila L. Pounds, slpound@sandia.gov. Posted 12/13/99 (W-SN407952).

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