Liquid metal batteries have been introduced as promising option to address the needs for new energy storage technologies. Currently, batteries based on sodium and zinc are under development and a favorable option due to their high theoretical cell potential, readily abundant materials, and cost-advantages. Nevertheless, they face the problem of self-discharge, which makes it inevitable to understand fluid dynamics in the whole cell. Motivated by that, several types of fluid mechanic instabilities in Na-Zn liquid metal batteries are identified and discussed here. On the one hand they can jeopardize secure operation, but on the other hand they can also improve mixing and increase the cell efficiency. In doing so, realistic cell as well as operation parameters are included and dimensionless numbers for identifying critical conditions are presented. The phenomena with highest significance for the discussed batteries are solutal convection, swirling flow, electrocapillary Marangoni convection, and droplet formation. Still, many open research questions remain and we aim at motivating researchers to dig deeper into some of these topics to contribute to an improved cell design and performance.

中文翻译：

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Na-Zn 液态金属电池的流体力学


液态金属电池已被引入作为满足新能源存储技术需求的有前途的选择。目前，基于钠和锌的电池正在开发中，由于其高理论电池潜力、易于丰富的材料和成本优势，这是一个不错的选择。然而，它们面临着自放电的问题，这使得理解整个细胞中的流体动力学变得不可避免。受此启发，本文确定并讨论了 Na-Zn 液态金属电池中的几种类型的流体力学不稳定性。一方面，它们会危及安全运行，但另一方面，它们也可以改善混合并提高电池效率。在此过程中，包括真实的单元和操作参数，并提供了用于识别关键条件的无量纲数字。对所讨论的电池最重要的现象是溶质对流、漩涡流、电毛细管马兰戈尼对流和液滴形成。尽管如此，仍有许多悬而未决的研究问题，我们的目标是激励研究人员更深入地研究其中一些主题，为改进细胞设计和性能做出贡献。