Patterned Battery Exterior Material for Repetitive Bending Durability
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Solution Overview
Problem
Flexible batteries face damage and safety issues due to repetitive bending, leading to electrolyte leakage and reduced capacity, as conventional exterior materials fail to effectively disperse compressive and tensile stresses.
Innovation Solution
The exterior material is patterned in the transverse direction (TD) to enhance compressive stress, increasing resistance to deformation and minimizing damage, with the pattern formed using upper and lower molds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If pattern processing is performed by pressing upper and lower molds on the exterior material, then the initial modulus of elasticity increases and force is dispersed, but the exterior material may still be damaged under repetitive bending and compressive stress
Solution Approach 1:
The patent applies curvature to the exterior material surface by forming convex and concave patterns. This curvature transformation allows the material to better absorb and disperse compressive stresses during bending, preventing stress concentration and improving durability while maintaining flexibility.
Solution Approach 2:
The patent changes the physical parameters of the exterior material by forming three-dimensional convex and concave patterns with specific dimensions (convex pattern height: 0.1-1.0 mm, concave pattern depth: 0.1-1.0 mm, pattern pitch: 1-10 mm). These parameter changes enhance the material's ability to withstand compressive stress while maintaining flexibility.
2Stress or pressure
If the exterior material is made more resistant to deformation through pattern processing, then compressive stress is increased, but the material may become more prone to damage from internal electrode assembly forces
Solution Approach 1:
The patent applies local quality by creating specific convex and concave patterns at different locations on the exterior material. The convex patterns provide compression resistance while the concave patterns accommodate expansion, creating locally optimized stress distribution that prevents both compressive damage and internal force damage.
Solution Approach 2:
The three-dimensional convex and concave patterns create curved surfaces that naturally distribute stresses. The curvature allows the material to withstand compressive forces from external bending while also accommodating expansive forces from internal electrode assembly deformation without concentrated stress points.
Data Source
AI summary
An exterior material to be used for a battery comprises at least one pattern part formed in a transverse direction (TD) of the exterior material, wherein the TD of the exterior material is a width direction of a battery including the exterior material, and a machine direction (MD) of the exterior material is a longitudinal direction of the battery including the exterior material.