Life testing of a nine-couple hybrid thermoelectric panel

Life test data are presented for a nine couple thermoelectric panel of hybrid couples tested at an average hot junction temperature of 840 C (1113 K). In the hybrid couple, a hollow cylinder of p-type Si-Ge is used to encapsulate a segmented PbTe/Si-Ge n-leg. The output power and internal resistance of the panel as well as the resistances of the individual hybrid couples are presented as functions of test time covering a period of more than 4200 hours. Test results indicated improved stability relative to hybrid couples tested at higher temperatures. Thermal cycling of the panel resulted in an order of magnitude increase in room temperature resistance. However, very little change in resistance at operating temperatures was noted following the thermal cycles.