The Effects of Stack Configurations on the Thermal Management Capabilities of Solid Oxide Electrolysis Cells

In this study, we analyze the impacts of various stack configurations of a solid oxide electrolysis cell (SOEC) that includes U-type and Z-type stack structures as well as co-flow and counter-flow configurations. The primary focus of this study is to analyze the impact of these SOEC stack configurations on the temperature distribution within the stack and the temperature variations of key components. Furthermore, by predicting the thermal stress and thermal deformation of individual SOEC components, the study can provide design guidelines for enhancing the durability of the SOEC stack. Among various SOEC stack configurations, the counter-flow design outperformed others in temperature uniformity and component temperature variation. The Z-type stack structure slightly surpassed the U-type in flow uniformity, while both had a minimal influence on thermal management. Besides conventional flow-field configurations, such as the parallel flow field, we introduce a metal-foam-based flow-field design and analyze the effects of using metal foam to ensure flow uniformity within the stack and achieve temperature uniformity. The metal foam design has a lower average temperature (2-5 degrees C) and increment T (4-7 degrees C) compared to the parallel flow field in each cell, but this improvement is accompanied by a substantial pressure-drop: 2359.3 Pa for vapor flow (11.7 times higher) and 4409.0 Pa for air flow (4.6 times higher). Additionally, structural analysis was performed using CFD temperature data. The co-flow configuration induced higher thermal stress at the front of the stack, whereas the counter-flow configuration mitigated thermal stress in the front cells. The metal foam structure consistently demonstrated a reduction in thermal stress across all cells by about 1 MPa, highlighting its potential to alleviate thermal stress in SOEC stacks. This study presents a novel CFD analysis approach for a 10-cell SOEC stack, enabling the development of an optimized stack design with improved heat and flow distribution. The integrated CFD-FEM analysis provides reliable thermal stress data that elucidates the correlation between temperature and stress distributions within the stack.