Degradation Analysis of SOFC Performance for Long-Term Operation with High Fuel Utilization (2)

Three types of SOFC stacks have been operated in a NEDO’s project from FY2020 to FY2024 in order to clarify the technical issues for high efficiency and toughness of SOFC stacks and establish the methods for advanced degradation diagnosis of SOFC stacks. Long-term durability tests of two types of SOFC stacks as flatten-tubular type and planar type have been conducted toward 20,000 h under the high fuel utilization at 80 and 85 %, respectively close to the operational limits of the stacks. In addition, the degradation factors of SOFCs were analyzed by using the electrode polarization model developed by CRIEPI. As a result, cathode overvoltage and IR loss were the major degradation factors in the durability tests over 10,000 h.