Stress field and failure probability analysis for the single cell of planar solid oxide fuel cells
Stress field and failure probability analysis for the single cell of planar solid oxide fuel cells
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DOI：
10.1016/j.jpowsour.2008.04.027
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发表时间：
2008-08
影响因子：
9.2
通讯作者：
Tao Zhang;Qingshan Zhu;W. Huang;Z. Xie;X. Xin
中科院分区：
文献类型：
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作者：
Tao Zhang;Qingshan Zhu;W. Huang;Z. Xie;X. Xin
建立了固体氧化物燃料电池（SOFC）单电池残余热应力的解析模型，该电池由8mol%Y2O3稳定的氧化锆/氧化镍（8 YSZ/NiO）厚阳极、致密8 YSZ电解质和多孔锰酸锶镧（LSM）阴极组成。模拟结果表明，在室温条件下，由于电池各组成部分的收缩失配，电池中的主应力主要为拉应力，而电解质和阴极则处于压应力状态。当其他两个部件的厚度固定时，其中一个部件的应力随其厚度的增加而减小，阳极中拉应力的减小将导致阴极和电解质中压应力的增加，反之亦然。分析还表明，阳极是最容易断裂的部分，因为拉伸热应力如此之高，它达到了阳极材料的断裂强度。采用威布尔统计量来估计阳极的失效概率。模拟结果表明，阳极失效概率随阳极厚度的增加而减小，随电解液厚度的减小而减小。对于电解质厚度为10μm、阴极厚度为20μm的电池，为了保持阳极失效概率小于1 E-06，阳极厚度应大于0.7mm。
An analytical model is developed to predict the residual thermal stresses in a single cell of solid oxide fuel cells (SOFCs), which consists of a thick porous 8mol% Y2O3stabilized zirconia/nickel oxide (8YSZ/NiO) anode, a dense 8YSZ electrolyte and a porous lanthanum strontium manganite (LSM) cathode. The simulated stresses in the cell at room temperature, which are resulted from the contraction mismatch of its components, indicate that the major principal stress in the anode is tensile while the electrolyte and cathode are under compressive stresses. The stress in one component decreases with the increase of its thickness when the thicknesses of the other two components are fixed, and the decrease of the tensile stress in the anode will cause the increase of the compressive stresses in both the cathode and the electrolyte, and vice versa. The analysis also reveals that the anode is the part that is most susceptible to fracture since the tensile thermal stress is so high that it reaches to the fracture strength of the anode material. The Weibull statistic is employed to estimate the failure probability of the anode. The simulation results indicate that the anode failure probability decreases with the increase of the anode thickness and the decrease of the electrolyte thickness. To keep the anode failure probability less than 1E−06, the anode thickness should be greater than 0.7mm for a cell with an electrolyte thickness of 10μm and a cathode thickness of 20μm.