Pouch Cell Bridge Crack Prevention via Metal Layer Thickness Ratio
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Solution Overview
Problem
Pouch cells experience cracks in the bridge portion due to gases generated during charging and discharging, leading to potential damage and loss of functionality.
Innovation Solution
A method for manufacturing pouch cells involves molding a pouch film with a metal layer to form cup portions on both sides of a bridge portion, ensuring a thickness ratio of the metal layer in the bridge portion to the cup portion depth exceeds 0.006, and sealing the pouch film with specific distance requirements to prevent cracks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If cup portions are formed on both sides of the pouch film to increase energy density, then energy density is improved, but cracks occur in the bridge portion due to internal gas generation
Solution Approach 1:
The patent applies parameter changes by establishing a specific thickness-to-depth ratio (T/D ≥ 0.006) for the metal layer in the bridge portion relative to cup portion depth. This quantitative parameter control ensures the bridge portion has sufficient structural strength to resist cracking while maintaining the dual cup configuration for high energy density. The metal layer thickness is specifically optimized to balance structural integrity with electrochemical performance.
Solution Approach 2:
The patent uses composite materials by incorporating a metal layer within the pouch film structure at the bridge portion. This metal reinforcement layer provides enhanced mechanical strength and crack resistance to the bridge portion, allowing it to withstand internal gas pressure while maintaining the pouch cell's flexibility and electrochemical functionality. The composite structure combines the advantages of both the pouch film and metal layer.
2Strength
If the metal layer thickness in the bridge portion is increased to prevent cracks, then bridge portion strength is improved, but manufacturing complexity increases
Solution Approach 1:
The patent simplifies manufacturing by establishing a clear quantitative criterion (T/D ≥ 0.006) that guides the metal layer thickness selection. This parameter-based approach provides manufacturers with a straightforward design rule, eliminating the need for complex simulations or iterative testing to determine appropriate thickness. The criterion directly links geometric parameters to structural performance, streamlining the manufacturing process.
Data Source
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AI summary
The present invention relates to a pouch cell that can prevent the generation of cracks in the bridge portion of a pouch due to gases generated during charging and discharging, and a method for manufacturing the same. The method for manufacturing a pouch cell comprises (a) a step of molding a pouch film comprising a metal layer so as to form a pair of cup portions capable of accommodating an electrode assembly at both sides of a bridge portion in the pouch film, wherein in step (a), the pouch film may be molded so as to satisfy an equation of T/D>0.006, where a thickness of the metal layer in the bridge portion is T mm, and a depth of the cup portion is D mm after molding.