Stack Performance

The performance of 5x4 multiple cell stacks using multilayers of type B were investigated with Ni-Cr alloy or LaCr03 ceramics interconnects. The other testing conditions were same as those of single cell. The I-V/P characteristics of the stacks are shown in Fig. 6 and 7. The maximum power of the stacks with alloy and ceramics interconnects were 465W (0.23Wcm"2) and 472W (0.24Wcm'2), respectively (Uf=40%). The results of alloy and ceramics interconnects were scarcely different. To estimate the long-term reliability, the stacks were operated for 500h.

During the testing, some multilayers were broken down. The degradation rate of terminal voltage except the broken multilayers were 0.39mVh"' with alloy interconnects and O.OOmV h"1 with ceramics interconnects. For the stacks with alloy interconnects, the Cr ions were detected in the cathode adjacent to the interconnects. The diffusion of Cr ions seems to increase the polarization resitivity of the cathode. The gradual increase of polarization resitivity was considered to result in the degradation of the stack with alloy interconnects.

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