Patterned Battery Exterior Material for Edge Damage Under Bending

The patent applies different pattern depths at different locations on the exterior material. Specifically, the pattern depth at the edge portion is greater than the pattern depth at the central portion. This local differentiation allows the edge portions (which experience higher stress during bending) to have enhanced stress distribution capabilities, while the central portion maintains sufficient flexibility. This resolves the contradiction by locally optimizing the pattern depth to match the stress distribution requirements at different locations.

The patent introduces a new dimension of pattern depth variation across the exterior material surface. Instead of using a uniform pattern depth, the pattern depth is varied spatially, creating a gradient structure. This dimensional change in pattern depth allows the exterior material to simultaneously achieve high initial modulus for stress dispersion and extended fatigue life by accommodating repeated bending through the differentiated depth structure.

The patent implements local quality by creating regions of different pattern depths across the exterior material. The edge portions with greater pattern depth provide enhanced rigidity and stress distribution to resist compressive forces from the electrode assembly, while the central portion with lesser pattern depth maintains flexibility for bending and folding. This spatial differentiation resolves the contradiction between strength and bending durability.

The patterned exterior material effectively creates a composite structure where regions with different pattern depths function as distinct material zones. The deeper patterns at the edges create a structurally reinforced composite that resists compressive forces, while the shallower patterns in the center create a more compliant composite region that accommodates bending. This composite approach allows simultaneous achievement of strength and flexibility.