Characterization of layered anisotropic properties for Li-ion battery pouch film and its application to forming

With the growth of electric vehicle market, lithium-ion pouch battery is attracting great attention. In this work, the deformation and failure behavior of pouch film was investigated. A constitutive model from property characterization was also derived. Tensile testing and nanoindentation combined with optimization was introduced for identifying layered properties of the film. Nanoindentation predetermined yield stress and hardening coefficients for different layers enhances material characterization. The optimization accurately identified layered properties considering stress and strain directionalities. Applying the method to the Yoshida buckling test and battery pouch forming, the proposed multi-layered model proved more accurate than the single-layer model.