重力扰动下液态金属电池内部的多场耦合特性分析

Multi-field Coupling Characteristics of Liquid Metal Battery Under Gravity Disturbance

液态金属电池由于其低成本、长寿命的优异性能,有望成为面向电网的储能手段。然而,液态金属电池工作过程中存在多种流体不稳定性,外界的晃动等扰动则有可能加剧这些不稳定性对电池运行的影响,甚至导致液–液界面失稳与短路。为探究晃动对现有大容量液态金属电池的影响,该文建立综合考虑电化学反应、流体动力学、传热与传质的二维轴对称200Ah Li||Bi电池模型,采用不同放电倍率的放电电压数据完成模型验证,并在重力扰动下研究热致流动与磁致流动对电池内部传质及放电特性的影响,并探究不同电解质层厚度下的短路风险。研究表明,液态金属电池对重力扰动具有一定的鲁棒性,但在电解质厚度较小时具有较大的短路风险。

Liquid metal battery(LMB) has become a possible solution for grid scale energy storage applications due to its low cost, long life and great performance. However, there are a variety of instabilities during operation. External disturbances, such as sloshing, would further aggravate the influence of the instabilities, even lead to short circuit of the batteries. In this paper, a 2-D axisymmetric model of a 200 Ah Li||Bi LMB was developed to investigate the impact of sloshing on electrochemical performance of the large capacity LMBs.The model considered the electrochemical reactions, fluid dynamics, heat and mass transfer process in the LMBs to simulate the thermal induced flow and the magnetic induced flow. It was validated by experimental voltage data at different discharge ratios. Under gravity disturbance, influence of the induced flows to the mass transfer and discharge performance was studied, and the short-circuit risk of the LMBs with different electrolyte thickness was presented. The results showed that the LMB was robust to the gravity disturbance to some extent. However, when the electrolyte thickness was small, there was a large risk of short circuit.