固体氧化物燃料电池阳极电解质界面的建模和分析

发布时间：2018-03-11 15:04

本文选题：固体氧化物燃料电池　切入点：COMSOL　出处：《华中科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：固体氧化物燃料电池(SOFC)由于它的高效率、很强的燃料灵活性和环境友好等优点是未来能源市场上很有前景的能量转化装置,但是目前它还存在很多的不足,阻碍了其更广泛的应用。因此,为了提高固体氧化物燃料电池的性能及竞争力,研究人员采取了各种方法从各个方面进行尝试。本论文中将建立模型对平板式固体氧化物燃料电池进行数值模拟,并尝试从优化阳极和电解质界面的角度提高SOFC的电化学性能。本文的模拟工具是有限元软件COMSOL,文中利用它分别成功地对含有较厚和较薄电解质层的SOFC阳极-电解质-阴极重复单元进行了二维稳态下的数学建模,模型的等式略有不同,但都以氢气为燃料气体并考虑了电池内部的电荷,气体传输定律和电化学反应过程。在先一个模型中,文中建模测试了五种具有不同阳极/电解质界面的电池,以找出具有最佳电化学性能的阳极/电解质界面电池。结果显示较深椭圆型的界面在不同的固定电压下比其他四种界面电池获得更高的电流密度,对其进一步的优化研究发现,此椭圆形态在阳极/电解质界面处越深、越密集,电池总的性能表现就越好,和平面界面电池比较,理想下能获得最大32%的电流密度的提升。利用第二个模型本文着重研究了阳极支撑型SOFC中矩形的电极和电解质界面对单电池性能的影响,模拟得到了电池内部的气体、电子离子电势、活化过电势等的分布,发现参数gap厚度为100μm的矩形界面单电池电流电压曲线明显优于平面界面电池,其最大功率密度提升可以达到48%,并具体分析了较高的矩形界面对电池性能提升作用的原因,提出了影响此提升的因素,同时与实验数据的比对还验证了此模拟的可靠性。本论文提出了固体氧化物燃料电池中界面曲折因子的概念,并验证了其与电池电化学性能之间的正相关关系,对未来从燃料电池电解质/电极界面角度优化燃料电池的性能的提供了很好的方向。
[Abstract]:Solid oxide fuel cell (SOFC) is a promising energy conversion device in the energy market in the future due to its high efficiency, strong fuel flexibility and environmental friendliness, but it still has many shortcomings. Thus, in order to improve the performance and competitiveness of solid oxide fuel cells, In this paper, a model is built to simulate the solid oxide fuel cell (SOFC). In this paper, the finite element software COMSOL is used to improve the electrochemical performance of SOFC from the point of view of optimizing the interface between anode and electrolyte. In this paper, the SOFC anode electrolysis with thicker and thinner electrolyte layers is successfully carried out by using the finite element software COMSOL. Two dimensional steady state mathematical model of mass-cathode repeat unit is presented. The equation for the model is slightly different, but both use hydrogen as the fuel gas and take into account the charge, the law of gas transfer and the electrochemical reaction process inside the cell. In this paper, five kinds of batteries with different anode / electrolyte interfaces are modeled and tested. In order to find out the anode / electrolyte interface battery with the best electrochemical performance, the results show that the deep elliptical interface obtains higher current density than the other four interface cells at different fixed voltages. The deeper and denser this ellipse is at the anode / electrolyte interface, the better the overall performance of the battery is, compared with the planar interface battery. In this paper, the effect of the rectangular electrode and electrolyte interface on the performance of a single cell in anodic supported SOFC is studied, and the gas inside the cell is simulated. The distribution of electron ion potential, activation overpotential and so on shows that the current and voltage curves of rectangular interface cells with the thickness of 100 渭 m gap are obviously superior to those of planar interface cells. The maximum power density can be increased to 48. The reason of the effect of the high rectangular interface on the battery performance is analyzed, and the factors that affect the performance of the battery are put forward. In this paper, the concept of interface zigzag factor in solid oxide fuel cell (SOFC) is proposed, and the positive correlation between it and the electrochemical performance of SOFC is verified. It provides a good direction for optimizing the performance of fuel cell from the point of view of electrolyte / electrode interface.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM911.4

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