- مبلغ: ۸۶,۰۰۰ تومان
- مبلغ: ۹۱,۰۰۰ تومان
A short stack composed of six micro-tubular fuel cells was fabricated in order to study its electrochemical performance under different electrical connection configurations (parallel, series and parallel-series) at intermediate temperatures. Two cells were in the Ni-YSZ/YSZ/Pr2NiO4-YSZ system and four were in the Ni-YSZ/YSZ/Nd2NiO4-YSZ configuration, of which one failed following testing at 600 °C. Overall, individual cells had similar performance delivering 202, 302 and 340 mW/cm2 at 600, 650 and 700 °C, respectively. The stack delivered a maximum of 7.40, 10.32 and 11.56 W at these temperatures. No significant differences were found among different arrangements. However, as expected, the stack performance was most affected by the malfunctioning cell under a series arrangement at 600 °C. Since the parallel-series configuration delivers an intermediate voltage and current and similar power to the parallel or series connections, it can be more suitable for stack assembly. Such an arrangement also offers the possibility of replacement of a stack module in case a cell fails in that module during operation. A repairable fuel cell stack eliminates the negative economic impacts caused by a malfunctioning cell which, in extreme cases, can lead to the complete loss of the valuable energy conversion device.
In this research the incorporation of high performing nickelate cathodes into a fuel cell stack was evaluated. Nd-nickelate and Pr-nickelate cathode performances were studied in the 600– 700 C temperature range. No significant difference was observed in the performance with the power generation being within a 10% range. Overall, individual cell performances were in good conformity with each other making the results reproducible. The stack was tested under different electrical connections for which similar powers were derived. Incorporation of a malfunctioning fuel cell into the stack at 600 C affected the power and OCV of the series arrangement the most and the parallel arrangement the least. Using mixed series and parallel combinations not only offers a high current or voltage and similar power performance, but also is safer to run in case any cell fails during operation. A stack with the cells connected under a mixed arrangement can be repaired in case a cell in a module fails by replacement of the corresponding module. The repairability is vital for commercialization of fuel cell stacks by preserving the energy conversion device which can be feasible by proper selection of electrical connections among the fuel cells.