High-performance half-Heusler thermoelectric devices through direct bonding technique
High-performance half-Heusler thermoelectric devices through direct bonding technique
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DOI：
10.1016/j.jpowsour.2021.229695
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发表时间：
2021-03-03
影响因子：
9.2
通讯作者：
Priya, Shashank
中科院分区：
文献类型：
--
作者：
Nozariasbmarz, Amin;Saparamadu, Udara;Priya, Shashank
固态热电发电机（TEG）是一种很有前景的余热回收解决方案。然而，它们通常面临转换效率较低、缺乏可靠的高温器件制造工艺和长期稳定性的问题。为了在 TEG 中实现高电转换效率 (ECE)，至关重要的是，与高 TE 材料品质因数 zT 相结合，还有可靠的 TE 模块制造工艺。这项研究表明，即使在高温 (>600 °C) 下，TEG 制造工艺也能降低金属电极和 TE 腿之间的热接触电阻和电接触电阻。该制造方法使用 p 型 ZrCoSb 基和 n 型 ZrNiSn 基 half Heusler TE 材料进行了演示。高温钎焊材料用作填料，可以将 TE 腿直接粘合到铜电极，而无需对腿进行金属化。该技术通过最大限度地减少 TE 腿/电极界面处的接触电阻和扩散，提高了 TEG 在高温下的性能和稳定性。所制造的模块具有 -11.5 Wcm? 的高功率密度？ 2 和 670 °C 温度梯度下的 ECE 为 9.5%。该模块在 550 °C 的空气中长时间浸泡，发现其退化程度可以忽略不计。这些结果对于推进 TE 模块在废热回收应用中的应用前景非常广阔。
Solid-state thermoelectric generators (TEGs) are promising solution for waste heat recovery. However, they typically suffer from lower conversion efficiency, lack of reliable high temperature device fabrication process and long-term stability. In order to realize high electrical conversion efficiency (ECE) in TEGs, it is critical that in conjunction with high TE materials figure of merit, zT, there is also a reliable TE module fabrication process. This study demonstrates the TEG fabrication process that results in reduced thermal and electrical contact resistances between metal electrodes and TE legs, even at high temperatures (>600 ?C). The fabrication approach is demonstrated using p-type ZrCoSb-based and n-type ZrNiSn-based half-Heusler TE materials. High temperature brazing material is used as a filler that enables direct bonding of TE legs to the copper electrode without metallizing legs. This technique improves the TEG performance and stability at high temperatures by minimizing the contact resistance and diffusion at TE leg/electrode interface. The fabricated modules exhibit a high power density of -11.5 Wcm? 2 and an ECE of 9.5% at 670 ?C temperature gradient. The module was exposed to longtime soaking at 550 ?C in air and was found to exhibit negligible deterioration. These results are highly promising for advancing the TE modules in waste heat recovery applications.