Study of the Magnetohydrodynamic Instability and a New Suppression Method in Liquid Metal Batteries

As a strong candidate for energy storage applications, Liquid Metal Batteries (LMBs) have the advantages of higher current density, longer cycle life, and simpler manufacturing of large-scale storage systems. Owing to the all-liquid construction, various kinds of Magnetohydrodynamic instabilities (MHDIs) are present in LMBs. In this paper, an in-depth study of the evolution process of MHDIs within LMBs has been conducted. By analyzing the characteristic velocity, the growth rate of instabilities γ has been defined so that the critical Hartmann number at which the instability occurs can be ascertained. A new critical parameter, mixed Reynolds number Remix, has been introduced to determine the duration of stable battery operation across varying charging/discharging currents, including those that may surpass the prescribed safe limits. Finally, a method for mitigating magnetohydrodynamic instability in LMBs through the configuration of busbar current is proposed, which can be seamlessly integrated with parallel battery packs. A comparative analysis of LMBs operation with/without bus current configuration reveals that when bus current is appropriately configured, the magnetic field strength within the battery undergoes a notable reduction of 40%, leading to a significant suppression of instability. The conclusions offer theoretical underpinnings for the application of LMBs in large-scale grid-level energy storage systems.