Testing And Performance Study Of Planar SOFC Single Cell With Large Active Reaction Area

Anode-supported planar solid oxide fuel cells (SOFCs) with dimension from 5×5 cm² to 15×15 cm² have been successfully fabricated by tape casting, screen printing and single step co-firing technologies, which shows a potential way of cost-effective for mass production. SEM technology was used to characterize the microstructure of the cross section of the cell, XRD technology applied to show the X-ray diffraction diagram of cell anode layer before and after the reduction and a series of electrical testing conducted. The typical cell with dimension of 10×10 cm² (active reaction area of 9×9 cm²) obtained open circuit voltage (OCV) of 1.15 V and power density of 770 mW/cm² at current density of 950 mA/cm² at 750°C. The performance degradation is lower than 1.56%/1000 h and the cell was proved to survived five thermal cycle. When external reformed methane gas was used as fuel, the cell showed no obvious performance decrease compared to that using pure hydrogen as fuel. The test results have demonstrated that the as-prepared large size cells have excellent performance and reliability, which is ready for SOFC stack assembly. In SOFC single cell test progress, factors which effects the cell performance have been studied. Among these factors,for the contact resistance and sealant most. In experiment, the contact between current collector and electrode was optimized by employing LCN (LaCo_0.6Ni_0.4O₃) ceramic paste and Ni paste as cathode and anode contact materials, respectively.In order to prepare for high performance large size anode-supported planar solid oxide fuel cell (SOFC) and avoid the gas distribution difference during the test, in this research single cell with dimension of 10×10 cm² (active reaction area of 9×9 cm²) was divided into 9 galvanically separated segments (each segment with dimension of 2.8×2.8 cm²) to measure the local performance and temperature. Each segment was measured independently about the current-voltage curve and the local temperature. For comparison, computational fluid dynamics (CFD) was used to simulate the gas distribution in the cathode side. Both the simulation and experimental results show an inhomogeneous distribution of gas during the test. This work is crucial to design large size SOFC single cell with optimization of the gas distribution layer.