Analysis Of The Residual Stress In Cone-Shaped Tubular Solid Oxide Fuel Cell

The Cone-shaped Tubular Solid Oxide Fuel Cell has a very good application prospect in the portable energy field due to its advantages of simple preparation,easy sealing,good thermal cycle performance and high output voltage.Due to the difference in thermal expansion coefficient of different parts of the SOFC,it causes a large residual stress during the preparation process.If the relevant parameters are not properly selected,it is likely to cause microcracks or even cracks in the cell.Therefore,the research on the residual stress of the cell has received wide attention from scholars in recent years.Nowadays,there are many researches on the residual stress of P-SOFC,tubular SOFC and micro-tube SOFC,but there is little research on the residual stress of Cone-shaped Tubular SOFC.In order to study the influence of residual stress generated in the sintering process Cone-shaped Tubular SOFC on the mechanical properties and service life of SOFC,a two-dimensional axisymmetric model of Cone-shaped Tubular SOFC was established by using COMSOL Multiphysics software.The electrode composition,porosity and structural parameters were analyzed.The influence law on the residual stress of the cell provides a theoretical basis for the design of the cone tube SOFC in the future.The specific research contents of this paper are as follows:1.Firstly,the effects of Ni composition,cathode LSM composition,anode porosity and cathode porosity on the residual stress of the cell were studied.It is found that the increase of Ni content will lead to the increase of residual stress of various components of the cell,which is not conducive to the mechanical stability of SOFC.Considering the structural stability of the Cone-shaped Tubular SOFC,the volume fraction of Ni should not be too large.The influence of cathode LSM content on the residual stress of the cell is mainly concentrated on the cathode itself.The change of the volume fraction of LSM has little effect on the residual stress of the anode and the electrolyte.Increasing the porosity of the anode is beneficial to alleviate the residual stress inside the SOFC of the cone.Properly increasing the anode porosity reduces the damage of the anode.However,considering the other properties of the cell,the porosity should not be too large.2.The residual stress of SOFC in cone tube is closely related to its structural parameters.Therefore,the influence of structural parameters on residual stress of Cone-shaped Tubular SOFC is further analyzed.It is found that the component thickness of the cell(anode,electrolyte and cathode)is the main factor affecting the residual stress of the Cone-shaped Tubular SOFC;while the large end diameter,internal height and small end diameter of the Cone-shaped Tubular SOFC have little effect on the residual stress,negligible.3.The residual stress on each component decreases with the increase of its thickness,and the influence of electrolyte thickness variation on the overall residual stress of the cell is much larger than that of the cathode;The relationship between the thickness of the Cone-shaped Tubular SOFC component under different electrode porosity is given.Compared with the MT-SOFC assembly thickness formula,it was found that when the electrolyte thickness and the cathode thickness are the same,the Cone-shaped Tubular SOFC minimum anode thickness is smaller than the MT-SOFC.4.The creep deformation of SOFC has a "relaxation" effect on cell stress,and the effect of creep deformation on thermal stress decreases with increasing creep time.At different temperatures,the probability of anode damage decreases with increasing creep time.However,the higher the temperature,the greater the effect of creep on the probability of damage,ie the faster the probability of damage decreases.