Mechanical failure modeling for cathode sheets

Binqi Li

doi:10.1016/j.jpowsour.2024.235586

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Mechanical failure modeling for cathode sheets

2024-12-01

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DOI：10.1016/j.jpowsour.2024.235586

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Abstract

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The mechanical integrity of the cathode is critical for the operation and safety of lithium-ion batteries (LIBs). This study presents a comprehensive exploration of the progression and underlying mechanisms of failure within LIB cathodes, employing a combination of experimental and numerical methodologies. First, shear and 180 degrees peel tests are designed and conducted to calibrate the parameter values governing the interface between the aluminium (Al) foil and the active layer, leveraging cohesive zone modeling (CZM). Furthermore, based on finite element modeling (FEM) and extended finite element modeling (XFEM), failure criteria and damage models are introduced to simulate the damage behavior of both Al foils and active layer. Notably, XFEM computes the initiation and expansion of the crack in cathode. The numerical simulation demonstrates a good correlation with the experimental observations, effectively delineating the failure process of the cathode. Moreover, a parametric analysis is conducted to study the influence of the active layer and interface on cathode failure. It reveals that as the failure strain of the active layer increases, the failure strain of the cathode rises, ultimately converging with the failure strain of an isolated Al foil. However, the failure strain of cathode decreases and then increases with increasing interface peel strength. At a peel strength of 304 N/m, the stress distribution within the active layer and the interface is more uniform compared to the lower peel s trength scenarios. Besides, the interface stress 2024.235586 transfer behavior leads to the failure of the Al foil in early. The results enhance our understanding of the failure process and mechanisms in LIB electrodes and thus provide guidance for the design and fabrication of cathode.

Keywords:

Lithium-ion battery safety

Cohesive zone modeling

Failure behavior of cathode

Extended finite element modeling

Interface effect