Reliable sealing design of metal-based solid oxide fuel cell stacks for transportation applications

Recently, metal-based solid oxide fuel cells (SOFCs) receive much attention as new power converting systems, and reliable sealing is an essential requirement for the metal-based SOFC stacks. In this study, metal-based SOFC stacks with a reliable sealing method are developed for transportation applications. For successful development, bolt-spring and hydraulic compression methods for stack tightening are discussed in terms of their applicability to vehicles. Then, detailed stack designs are developed to obtain sufficient compressive stress on the surfaces of the sealing gaskets based on the finite element method (FEM). To maintain the compression and heat insulation of the stack, a hot box is designed based on the thermogravimetric properties, shrinkage behaviors, and mechanical properties of sealing gaskets of mica and Thermiculite 866LS, and ceramic fiber insulating board. As a result, a 1-cell stack unit is successfully fabricated and tested based on the designs, and a sealing rate of 100 ± 0.78% is achieved at an operating temperature of 800 °C. This study investigates comprehensive stack and sealing design processes, and it has broad implications for reliable stack development.