In-situ temperature monitoring directly from cathode surface of an operating solid oxide fuel cell


Guk E., Ranaweera M., Venkatesan V., Kim J., Jung W.

APPLIED ENERGY, vol.280, 2020 (Journal Indexed in SCI) identifier identifier

Abstract

The electrode temperature distribution of a solid oxide fuel cell is an important parameter to consider for gaining better insight into the cell performance and its temperature-related degradations. The present efforts of measuring gas channel temperatures do not accurately reveal the cell surface temperature distribution. Therefore, the authors propose a cell-integrated multi-junction thermocouple array to measure the electrode temperature distribution from a working solid oxide fuel cell. In this work, the authors deposited a thin film/wire multi-channel thermal array on the cathode of a commercially-sourced solid oxide fuel cell. The temperature of the cell was measured under varying fuel compositions of hydrogen and nitrogen. The multi-channel array showed excellent temperature correlation with the fuel flow rate and with the cell's performance whilst commercial thermocouples showed a very dull response (10 similar to 20 degrees C discrepancy between thermocouples and the multi-channel array). Furthermore, cell temperature measurements via the multi-channel array enabled detecting potential fuel crossover. This diagnostic approach is applied to a working solid oxide fuel cell, yielding insights into key degradation modes including gas-leakage induced temperature instability, its relation to the theoretical open circuit voltage and current output, and propagation of structural degradation. It is envisaged that the use of the multi-thermocouple array techniques could lead to significant improvements in the design of electrochemical energy devices, like fuel cells and batteries and their safety features, and other hard-to-reach devices such as inside an internal combustion engine or turbine blades.