INTERCHANGEABLE VARIABLE CONDUCTANCE HEAT PIPES FOR SODIUM-SULFUR BATTERIES

THE SODIUM-SULFUR BATTERY IS A CANDIDATE ENERGY STORAGE MECHANISM FOR SATELLITES. THERMAL MANAGEMENT OF THE BATTERY CELLS IS REQUIRED DURING CHARGING AND DISCHARGING. PROPER THERMAL MANAGEMENT WILL ISOTHERMALIZE THE BATTERY CELLS BY PROVIDING THERMAL INSULATION DURING RECHARGE OR SUNLIGHT OPERATION AND PROVIDING A MEANS TO RADIATE EXCESS HEAT GENERATED DURING DISCHARGE OR ECLIPSE OPERATION. VARIABLE CONDUCTANCE HEAT PIPES (VCHP) WILL PROVIDE PASSIVE LIGHTWEIGHT TEMPERATURE CONTROL FOR THE SODIUM-SULFIDE CELLS FOR GEOSYNCHRONOUS-EARTH-ORBIT (GEO) AND LOW-EARTH-ORBIT (LEO). THE GOAL OF THIS PHASE I PROGRAM IS TO ESTABLISH INTERCHANGEABLE THERMAL MANAGEMENT DESIGNS USING VCHPS FOR A COMMON SODIUM-SULFUR BATTERY CELL CONFIGURATION. ONLY ONE BATTERY CELL CONFIGURATION IS REQUIRED AND CAN BE USED FOR GEO OF LEO APPLICATIONS. THE VCHP COOLING SCHEME WOULD SIMPLY MEET THE THERMAL REQUIREMENTS OF THE ORBIT MISSION AND AVOID THE NEED TO CONFIGURE THE BATTERY CELLS TO MEET THE THERMAL MANAGEMENT DESIGN FOR DIFFERENT ORBITS. THIS PHASE I EFFORT WILL FABRICATE AND TEST A PROOF-OF-CONCEPT VCHP TO DEMONSTRATE THERMAL MANAGEMENT FOR SODIUM-SULFUR BATTERY TO BE USED IN LEO.