Multiphysics analysis of flow uniformity and stack/manifold configuration in a kilowatt-class multistack solid oxide electrolysis cell module

Solid oxide electrolysis cells (SOECs) can convert excess electrical energy into hydrogen at high temperatures. However, widespread implementation of SOECs is impeded by performance degradation and reliability issues at large-sized stacks. The magnification effects of heat, flow, and reactions within the stacks are necessary to address the limitations. In this study, we focus on a 12 kW multistack module comprising four short stacks, each containing 24 cells. A novel numerical approach based on distributed resistance analogy is employed to predict the multiphysics transport phenomena at the multistack module level. The effects of varying cell/stack numbers on the uniformity of multiphysics are investigated. A distributed gas supply method is introduced to achieve even distribution of gaseous flow across different stacks. Notably, increasing the number of short-stacks enhances flow and temperature uniformities compared to single long-stack configurations. A unified buffer chamber is proposed to decrease the temperature difference to 42.2 K for the magnified mutlistack module. The flow uniformity index of a dual-stack module (2 stacks x 48 cells) exhibits a remarkable 17.1 % improvement over that of a single long- stack (1 stack x 96 cells). A four-stack module (4 stacks x 24 cells) demonstrates a 6.7 % increase in flow uniformity index compared to the dual-stack configuration.