The thermal conductivity of polymer electrolytes is one of the important parameters characterizing heat transport in lithium polymer batteries. Experimental measurements, over the temperature range from 25 degrees C (298 K) to 150 degrees C (423 K), of the thermal conductivity of poly(ethylene oxide)-lithium salt electrolytes by a guarded heat flowmeter are described. Thermal conductivities of the poly(ethyene oxide) (PEO)-LiCF3SO3 polymer electrolytes were found to be relatively constant for the electrolytes with various concentrations of the lithium salt. Also, the thermal conductivity of the PEG-lithium salt electrolytes decreases with increasingly amorphous structure according to the order. PEO-LiClO4 congruent to PEO-LiCF3SO3 > PEO-LiN(CF3SO2)(2) > PEO-LiC(CF3SO2)(3).