From concept to commercialization: A review of tubular solid oxide fuel cell technology

The reduced sealing difficulty of tubular solid oxide fuel cells (SOFCs) makes the stacking of tubular cell groups relatively easy, and the thermal stress constraints during stack operation are smaller, which helps the stack to operate stably for a long time. The special design of tubular SOFC structures can completely solve the problem of high-temperature sealing, especially in the design of multiple single-cell series integrated into one tube, where each cell tube is equivalent to a small electric stack, with unique characteristics of high voltage and low current output, which can significantly reduce the ohmic polarization loss of tubular cells. This paper provides an overview of typical tubular SOFC structural designs both domestically and internationally. Based on the geometric structure of tubular SOFCs, they can be divided into bamboo tubes, bamboo flat tubes, single-section tubes, and single-section flat tube structures. Meanwhile, this article provides an overview of commonly used materials and preparation methods for tubular SOFCs, including commonly used materials and preparation methods for support and functional layers, as well as a comparison of commonly used preparation methods for microtubule SOFCs. It introduced the three most important parts of building a fuel cell stack: manifold, current collector, and ceramic adhesive, and also provided a detailed introduction to the power generation systems of different tubular SOFCs. Finally, the development prospects of tubular SOFCs were discussed.