Masini Alessia, Strohbach Thomas, Šiška Filip, Chlup Zdeněk, Dlouhý Ivo
Institute of Physics of Materials, Academy of Science of the Czech Republic, 61662 Brno, Czech Republic.
Sunfire GmbH, 01237 Dresden, Germany.
Materials (Basel). 2019 Jan 18;12(2):306. doi: 10.3390/ma12020306.
The mechanical reliability of reversible solid oxide cell (SOC) components is critical for the development of highly efficient, durable, and commercially competitive devices. In particular, the mechanical integrity of the ceramic cell, also known as membrane electrolyte assembly (MEA), is fundamental as its failure would be detrimental to the performance of the whole SOC stack. In the present work, the mechanical robustness of an electrolyte-supported cell was determined via ball-on-3-balls flexural strength measurements. The main focus was to investigate the effect of the manufacturing process (i.e., layer by layer deposition and their co-sintering) on the final strength. To allow this investigation, the electrode layers were screen-printed one by one on the electrolyte support and thus sintered. Strength tests were performed after every layer deposition and the non-symmetrical layout was taken into account during mechanical testing. Obtained experimental data were evaluated with the help of Weibull statistical analysis. A loss of mechanical strength after every layer deposition was usually detected, with the final strength of the cell being significantly smaller than the initial strength of the uncoated electrolyte (₀ ≈ 800 MPa and ₀ ≈ 1800 MPa, respectively). Fractographic analyses helped to reveal the fracture behavior changes when individual layers were deposited. It was found that the reasons behind the weakening effect can be ascribed to the presence and redistribution of residual stresses, changes in the crack initiation site, porosity of layers, and pre-crack formation in the electrode layers.
可逆固体氧化物电池（SOC）组件的机械可靠性对于开发高效、耐用且具有商业竞争力的设备至关重要。特别是陶瓷电池（也称为膜电解质组件，MEA）的机械完整性至关重要，因为其失效会对整个SOC堆栈的性能产生不利影响。在本工作中，通过三球压球法弯曲强度测量来确定电解质支撑型电池的机械强度。主要重点是研究制造工艺（即逐层沉积及其共烧结）对最终强度的影响。为了进行此项研究，将电极层逐一丝网印刷在电解质支撑体上并进行烧结。在每一层沉积后进行强度测试，并在机械测试过程中考虑非对称布局。借助威布尔统计分析对获得的实验数据进行评估。通常在每一层沉积后都会检测到机械强度的损失，电池的最终强度明显小于未涂层电解质的初始强度（分别约为800 MPa和1800 MPa）。断口分析有助于揭示在沉积各层时断裂行为的变化。发现强度减弱效应背后的原因可归因于残余应力的存在和重新分布、裂纹起始位置的变化、各层的孔隙率以及电极层中的预裂纹形成。
