Study on Forming Performance of Aluminum-Plastic Film for Pouch Lithium-Ion Batteries

To ensure the reliability of aluminum-plastic film encapsulation for lithium-ion batteries，strict control of the aluminum layer thickness after forming is necessary. However，obtaining the thickness relies heavily on physical experiments，resulting in high cost for both early design optimization and later production process quality monitoring. In this paper，a combination of physical experiments and simulation modeling is adopted to establish a constitutive equation that can well characterize the mechanical properties of the pouch during forming. Additionally，a prediction method for the aluminum layer thickness based on the overall aluminum-plastic film thickness is proposed，enabling precise prediction of the aluminum-plastic film and aluminum layer thickness after forming. Furthermore，based on simulation Design of Experiments（DOE），key influencing factors are screened to construct a response surface model，facilitating rapid prediction and optimal parameter matching design for different products，which also provides a solution for online monitoring of forming quality during production. The results show that the multi-layer composite aluminum-plastic film exhibits obvious anisotropy during the plastic stage. The 3-parameters Barlat-Lian constitutive model effectively represents the anisotropic properties of the film，and outperforms the single-directional elastic-plastic model，achieving accurate prediction of the aluminum-plastic film performance after forming. The constructed response surface model can replace the refined finite element model，and have excellent prediction accuracy for the thickness of the composite aluminum-plastic film and the aluminum layer，with an error less than 5%. By optimizing the process parameters，the formed thickness of the aluminum layer can be increased by 10%~20%. The integrated development application APP can meet the requirements for quick design evaluation，parameters optimization，and online monitoring of the forming quality. © 2024 SAE-China. All rights reserved.