Multi-Physical Field Coupling Numerical Simulation And Performance Optimization Design Of Solid Oxide Fuel Cell With Double-Sided Cathodes

Solid oxide fuel cell(SOFC)is an efficient and clean power generation device.Its development is of great significance to control environmental pollution.There are still problems in the structural reliability and operational life of SOFC at high temperature,which hinders the development of SOFC commercialization.The complicated operating conditions inside the SOFC: mechanical field,thermal field,internal flow field,electric field and diffusion field in the SOFC are tightly coupled.It is difficult to directly observe the internal physical field of the cell through traditional experimental means,However,the numerical simulation method has low cost and high efficiency,can accurately obtain the physical field distribution inside the closed cell under high temperature operation.This paper conducts a simulation study on the internal operation process of symmetric double cathode(DSC)SOFC and the mechanical behavior of battery structure.The key factors affecting the performance of SOFC are analyzed,and the current collection design and operation conditions are optimized to provide theoretical support for improving the stability of SOFC.The main research contents and conclusions are as follows:(1)Based on the coupling theory of mechanical-thermal-electro-chemo multi physical fields,a new multi coupling numerical model of DSC-SOFC stack is established by integrating solid mechanics model,heat transfer model,electrochemical reaction model,gas flow model and species diffusion model.The validity of the model is verified by comparing with experimental data.(2)The discharge performance of the cell is simulated by using the established DSC-SOFC numerical model,and a feasible design scheme of collecting current is given.The results show that: under the same current collection mode,the DSC-SOFC has a more uniform component distribution and electrolyte current density in the counter flow configuration,and a more uniform temperature distribution in the co-flow configuration;The non-uniform temperature distribution in the reactor can be effectively improved by set current collection position at the gas at the inlet and outlet.(3)Based on the current collection scheme at the gas inlet and outlet,the cell performance and thermal stress of DSC-SOFC under 8 different current collection methods are simulated and calculated.The results show that thermal stress at the anode,electrolyte and cathode(PEN)is higher than that at other structures of the cell stack.The cell has a higher output power under the double-side current collection mode.When the anode current collection position is set at the anode gas outlet,the battery has a more uniform temperature distribution,and the maximum principal stress at the PEN structure is lower.Compared with other structures of PEN,the anode has a larger maximum principal stress.(4)Combined with Weibull failure statistics method,the failure probability of pen structure is calculated under different current collection designs,and the most ideal collector is given.The results show that the PEN structure has a higher failure probability when the anode current collection position is at the anode gas inlet;Among the electrodes,the failure probability of the anode structure is the largest,reaching 0.6 at most,which is the most vulnerable component in the electrodes;The failure probability is affected by the flow configuration,and the common flow side has a lower failure probability.