Simulation of potential and species distribution in a Li||Bi liquid metal battery using coupled meshes
Simulation of potential and species distribution in a Li||Bi liquid metal battery using coupled meshes
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DOI：
10.1016/j.electacta.2022.141413
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发表时间：
2022-10
影响因子：
6.6
通讯作者：
C. Duczek;N. Weber;Omar E. Godinez‐Brizuela;T. Weier
中科院分区：
文献类型：
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作者：
C. Duczek;N. Weber;Omar E. Godinez‐Brizuela;T. Weier
本文采用一维有限体积耦合网格模型，在忽略流体动力学效应的情况下，捕捉锂铋液态金属电池放电过程中的电位和物质分布，重点关注电池的电化学特性以及电解质和阴极中的质量传递。通过引入离散跃迁电位模型作为周期性边界条件来解决电池电位中的界面不连续，考虑了双电层中的界面反应。实现了一种类似平衡力的方法，以确保接口级计算的一致性。研究发现，质量传递和浓度梯度对电池过电位有显著影响，从而影响电池性能和电池电压。通过量化混合阳离子电解质Li b| | Bi电池中的过电压，可以表明扩散和迁移电流密度可能对电池电压产生反作用。此外，模拟的极限电流密度比实验测量的要低得多，这可以归因于电解质中的对流效应，这需要在未来的模拟中解决。该求解器基于开源库OpenFOAM，并在等效系统COMSOL多物理场上进行了全面验证，并用实验结果进一步验证。
In this work a 1D finite volume based model using coupled meshes is introduced to capture potential and species distribution throughout the discharge process in a lithium–bismuth liquid metal battery while neglecting hydrodynamic effects, focusing on the electrochemical properties of the cell and the mass transport in electrolyte and cathode. Interface reactions in the electrical double layer are considered through the introduction of a discrete jump of the potential modelled as periodic boundary condition to resolve interfacial discontinuities in the cell potential. A balanced-force like approach is implemented to ensure consistent calculation at the interface level. It is found that mass transport and concentration gradients have a significant effect on the cell overpotentials and thus on cell performance and cell voltage. By quantifying overvoltages in the Li|| Bi cell with a mixed cation electrolyte, it is possible to show that diffusion and migration current density could have counteractive effects on the cell voltage. Furthermore, the simulated limiting current density is observed to be much lower than experimentally measured, which can be attributed to convective effects in the electrolyte that need to be addressed in future simulations. The solver is based on the open source library OpenFOAM and thoroughly verified against the equivalent system COMSOL multiphysics and further validated with experimental results.