Cell integrated thin-film multi-junction thermocouple array for in-situ temperature monitoring of solid oxide fuel cells

Abstract

A thin-film multi-junction thermocouple array was developed and tested for multi-point simultaneous temperature measurements from an operating SOFC stack. The array requires only {N+1} number of wires/ thermo-elements for N number of independent temperature measuring points. Hence, it requires less number of lead wires than any available contact-temperature sensor requires for the same number of measurements. Because the multi-junction thermocouple array operates on the same principle of a conventional thermocouple, the Seebeck effect, it shares all the merits of a thermocouple. A thin-film multi-junction thermocouple array was sputter deposited on the cathode of a SOFC test cell and tested and evaluated up to 10500C from 200C. Temperature measured from the thermocouple array was compared with that from a commercial thermocouple placed adjacent to it during the test; they were in very good agreement within the entire temperature range that a SOFC stack generally operates.