Highly Thermal-Integrated Flame Fuel Cell Module with High Temperature Heatpipe

Abstract

Flame fuel cell(FFC) is a novel kind of fuel cell coupling rich-flame and solid oxide fuel cell(SOFC) together. With rich-flame as both heater and reformer, FFC takes advantages of quick start-up, no sealing and low cost. However, for the temperature distribution is determined by flame, temperature nonuniformity is a significant problem, especially along the axis direction of the tubular SOFC or within SOFC stacks. Due to great temperature gradient and insufficient thermal shock resistance, micro cracks occur inside the cell, resulting in a low open circuit voltage and failure of FFC. Relatively low temperature in partial regions of SOFC also leads to a low power density. In this paper, a high temperature heatpipe was introduced to a flame fuel cell module to lower the temperature gradient and improve the performance of the whole SOFC. A highly thermal-integrated FFC module with a two-layer porous media burner, micro-tubular SOFCs and an annular high temperature heatpipe was designed and tested. The temperature difference along the axial of the tubular SOFC decreased from 34°C/10 mm to 12°C/10 mm due to the high heat conductivity of the heatpipe. By integrating with a heatpipe, the power output for a single fuel cell increased from 0.88 W to 1.54 W at 0.7 V with a methane-rich flame at an equivalence ratio of 1.6. The FFC module with four cells showed considerable performance and had the potential for fabrication of FFC stacks.