电化学能量储存和转换体系多物理场模型的建立及其应用

Development and application of multiphysics models for electrochemical energy storage and conversion systems

电化学能量储存和转换技术已成为解决能源和环境问题的重要手段。如何解决大规模工业化应用过程中电化学能量储存和转换体系相关材料、器件的研发、设计、优化以及管理控制等关键科学和技术问题已经成为一个热点。本工作以锂离子电池、超级电容器和电解水制氢3个具体实例为对象,建立电化学系统多物理场模型。基于实验验证模型,探索了大容量软包电池内芯传递现象、电化学反应过程及电流分布间的相互作用;引入“静电像相关性”概念,研究超级电容器多级孔道内双电层及赝电容的分布规律;考虑PEM电解水制氢工程学上的瞬态问题,研究制氢装置电化学表征特性模拟及两相流传递现象对电解性能的影响。结果表明,大电流操作、导热性差的电池内芯材料显著加剧电池内芯内部电流及反应非均匀性,超级电容器微孔和介孔配比影响双电层及赝电容分布及离子传递过程,制氢装置部件需要高亲水性材料且保持流道中高液相饱和度来增强电解性能。由此可见,多物理场模型可以为材料设计、实际物理过程分析以及系统优化等方面提供理论和设计指导。

The use of electrochemical energy storage and conversion technology is a primary method for addressing energy and environmental problems.The key scientific and technological issues of its material development,optimization and design,and system management for industrial-scale applications have received a lot of attention.This paper describes three application cases:lithium-ion batteries,supercapacitors,and proton exchange membrane water electrolysis(PEMWE),as well as the multiphysics models that were developed for each.We discovered and investigated the interactions of transport phenomena,electrochemistry,and current density distributions in the large-format pouch cell based on such experimentally validated models;we introduced"electrostatic image forces"to study the effects of hierarchically porous structures on double layer and pseudocapacitance of the supercapacitor;we considered the transient-state issues in PEMWE engineering,and investigate the effects of two-phase flow transport phenomena on the electrolytic performance.The results show that high C-rate operations and jelly roll materials with low thermal conductivities significantly increase the heterogeneity of internal reactions and current density distributions.It also claims that the volume ratio of micro and mesopores influences the allocation of alternative capacitances in the hierarchical pores and ion transport processes.PEMWE requires materials with high hydrophilia and high liquid saturations in the flow channels to improve electrolytic performance.As a result,the multiphysics models can help with theoretical interpretation and optimization in the areas of material design,process analysis,and system management optimization.