Battery Pouch Chamfer Structure Prevents Peripheral Extrusion
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Solution Overview
Problem
The pouch-type secondary batteries experience extrusion of the periphery compared to the central region due to external pressure, leading to increased thickness and potential detachment of active materials from the electrode assembly.
Innovation Solution
A pouch design with a vessel-type bottom and cover-type top featuring a chamfer or step structure at the adjoining portions between the bottom surface and lateral surfaces, which helps maintain a constant thickness and prevents peripheral extrusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the pouch is manufactured in a vessel form by deep drawing process, then the bottom surface can hold the electrode assembly, but the periphery becomes thicker than the central region due to external pressure
Solution Approach 1:
The invention applies local quality by creating a recessed region at the periphery of the bottom surface with different geometric properties than the central region. This recessed region, formed by removing material or creating a depression, locally modifies the bottom surface geometry to prevent peripheral thickening while maintaining the overall vessel form structure needed to hold the electrode assembly.
2Strength
If the periphery of the pouch becomes thicker due to external pressure, then the structural strength may increase, but the active materials may detach from the electrode assembly
Solution Approach 1:
The recessed region creates a localized geometric feature that prevents the periphery from bulging outward under external pressure. By removing material or creating a depression at the periphery, the invention eliminates the mechanism that causes active material detachment while preserving necessary structural strength through the overall vessel form.
3Productivity
If the pouch is subjected to external pressure during vacuum packaging, then the pouch contracts to remove gases, but the periphery extrudes more than the central region
Solution Approach 1:
The recessed region at the periphery is specifically designed to accommodate and prevent extrusion during vacuum packaging. The local geometric modification creates a stress distribution pattern that allows the pouch to contract uniformly under external pressure without causing peripheral bulging or distortion.
Data Source
AI summary
A pouch for battery and a pouch type secondary battery, and more particularly, to a pouch for a battery having a space for containing an electrode assembly, the space being previously formed in a vessel form, and a pouch type secondary battery using the same. The pouch of the battery includes a vessel type bottom having a bottom surface and lateral surfaces; and a cover type top for covering an upper opening of the vessel type bottom, wherein a chamfer or step structure is formed at some of the adjoining portions of the bottom surface and the lateral surface, and the chamfer or step structure is viewed in cross section cut off along a plane which is perpendicularly to the bottom surface and approximately parallel to one surface of lateral surfaces. And the electrode assembly is contained by the pouch of battery to constitute a pouch type secondary battery according to the present invention.