No abstract

Management of solid oxide fuel cell (SOFC) thermal gradients is vital to limit thermal expansion mismatch and thermal stress. However, owing to harsh operation conditions of SOFCs and limited available space in stack configuration, the number of techniques available to obtain temperature distribution from the cell surface is limited. The authors previously developed and studied a thermocouple array pattern to detect surface temperature distribution on an SOFC in open circuit conditions. In this study, the performance in terms of mechanical durability and oxidation state of the thin film thermoelements of the thermocouple array on the porous SOFC cathode is investigated. A thin-film multi-junction thermocouple array was sputter deposited using a magnetron sputter coater. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) characterisation techniques were carried out to understand characteristics of the thin film before and after temperature (20 °C–800 °C) measurement. Temperature readings from the sensor agreed well with the closely placed commercial thermocouple during heating segments. However, a sensor failure occurred at around 350 °C during the cooling segment. The SEM and XPS tests revealed cracks on the thin film thermoelements and oxidation to the film thickness direction.

We present single‐step‐co‐sintering manufacture of a planar single‐chamber solid oxide fuel cell (SC‐SOFC) with porous multilayer structures consisting of NiO/CGO, CGO and CGO‐LSCF as anode, electrolyte, and cathode, respectively. Their green tapes were casted with 20 μm thickness and stacked into layers of anode, electrolyte, and cathode (10:2:2), then hot‐pressed at 2 MPa and 60°C for 5 minutes (deemed optimal). Subsequently, hot laminated layers were cut into 40 × 40 mm cells and co‐sintered up to 1200°C via different sintering profiles. Shrinkage behavior and curvature developments of cells were characterized, determining the best sintering profile. Hence, anode‐supported SC‐SOFCs were fabricated via a single‐step co‐sintering process, albeit with curvature formation at edges. Subsequently, anode thickness was increased to 800 μm and electrolyte reduced to 20 μm to obtain SOFCs with drastically reduced curvature with the help of a porous alumina cover plate.

A test was performed to determine the efficacy of a novel multi-channel thermocouple temperature sensor employing “N+1” array architecture for the in-situ detection of icing in cold climates. T-type thermoelements were used to fabricate a sensor with six independent temperature sensing points, capable of two-dimensional temperature mapping. The sensor was intended to detect the high latent heat of fusion of water (334 J/g) which is released to the environment during ice formation. The sensor was embedded on a plywood board and an aluminium plate, respectively by an epoxy resin. Three different ice accretion cases were considered. Ice accretion for all cases was achieved on the surface of the resin layer. In order to analyse the temperature variation for all three cases, the first 20 s response for each case was averaged between three cases. A temperature increase of (1.0 ± 0.1) °C and (0.9 ± 0.1) °C was detected by the sensors 20 s after the onset of icing, attributed to the latent heat of fusion of water. The results indicate that the sensor design is well-suited to cold temperature applications and that detection of the latent heat of fusion could provide a rapid and robust means of icing detection.