本文針對鋰離子電池內部的多孔介質因受到電極膨脹而被壓縮的現象進行探討。文獻回顧中提到，多孔介質基於不同的假設，會使用不同的力學模型，像是多孔彈性力學或黏彈性力學，來分析多孔介質的受力。為了探討鋰電池內部的多孔介質在受壓行為下的力學行為，與多孔材質受壓後對電池表現可能造成的影響，我們使用多孔彈性力學中的Mandel問題模型，模擬多孔介質受壓下的變化。 本文利用PETSc函式庫進行有限元素法模擬，探討多孔介質的性能。根據不同的曲線圖得出孔壓與位移在二維區域內的曲線分布變化。其中多孔介質的孔隙度、楊氏模數、泊松比、滲透率與體積模數，還有電解質液體的黏度與體積模數都設定為已知值。假定頂部和底部邊界是不透水層、可視為液壓絕緣，而側面邊界則暴露在空氣中、壓力設定為0。對上下板子施加壓應力的狀況下，採用多孔彈性力學的經典二維Mandel問題，模擬矩形區域內多孔介質孔壓分布與位移隨時間的變化。結果顯示，中心的孔壓分布會隨時間遞進而溢散減小。 ;This paper analyzes the phenomenon that the internal porous media of a lithium-ion battery is compressed due to electrode expansion. It is mentioned in the literature review that the porous media is based on different assumptions and uses different mechanical models, such as poroelasticity or viscoelasticity, to analyze the stress of porous materials. In order to explore the mechanical behavior of the internal porous media of a lithium-ion battery under compression and the possible impact on battery performance after the porous media is compressed, we use the Mandel problem model in poromechanics to simulate the change of porous materials under compression. We use the PETSc (Portable, Extensible Toolkit for Scientific Computation) function library to perform the finite element method simulation to discuss the performance of the porous media. According to different graphs, the curve distribution changes of pore pressure and displacement in a two-dimensional area are obtained. The porosity, Young′s modulus, Poisson′s ratio, permeability, and bulk modulus of the porous media, as well as the viscosity and bulk modulus of the electrolyte liquid, are all set to known values. Assume that the top and bottom boundaries are impervious and can be considered as hydraulic insulation, while the side boundaries are exposed to air and the pressure is set to zero. Under the condition of applying compressive stress to the upper and lower plates, the classical two-dimensional Mandel′s problem of porous elasticity is used to simulate the change in the pore pressure distribution and displacement of the porous media with time in a rectangular region. The results show that the pore pressure distribution in the center decreases with time and then the pressure release.
