Pouch Battery Sealing Strip with Dual-Line Edge Protection
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Solution Overview
Problem
The existing packaging of pouch lithium batteries has an uneven peel force distribution along the sealing strip, leading to insufficient packaging strength and safety risks, as the sealing strip provides only a single line of protection close to the battery cell body.
Innovation Solution
A battery cell design with a sealing strip that is sequentially formed with a first edge, a middle line, and a second edge, where the peel force at the first edge is greater than at the middle line, creating a dual line of protection to enhance packaging strength and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sealing strip provides only single line of protection at a side close to the battery cell body, then the packaging structure is simple, but the packaging strength and safety are insufficient
Solution Approach 1:
The sealing strip is designed with non-uniform peel force distribution, where the first edge portion has greater peel force than the middle portion. This local quality variation creates enhanced protection at critical edges while maintaining simpler structure elsewhere, resolving the contradiction between packaging strength and structural complexity.
Solution Approach 2:
The sealing strip is segmented into different functional regions: a first edge portion with higher peel force for primary sealing and a middle portion with lower peel force. This segmentation allows different parts of the sealing strip to perform different functions, improving overall packaging reliability without requiring a completely complex multi-layer structure.
2Strength
If the peel force is uniformly distributed along the sealing strip, then the manufacturing process is simple, but the packaging strength at critical edges is insufficient
Solution Approach 1:
The thermally-fusible resin layer is designed with transverse distribution, creating higher resin concentration at the first edge portion and lower concentration at the middle portion. This local quality variation in resin distribution directly controls the peel force distribution, achieving higher sealing strength at edges while maintaining manufacturability through controlled material distribution.
Solution Approach 2:
The resin arrangement density in the thermally-fusible resin layer is varied across different positions of the sealing strip. By changing the resin density parameter from uniform to transverse distribution, the peel force characteristics are optimized with higher values at edge portions, achieving improved sealing strength without fundamentally changing the manufacturing process.
Data Source
AI summary
A battery cell includes a battery cell body and a packaging body having a sealing strip that surrounds the battery cell body. The sealing strip is sequentially formed with a first edge, a middle line and a second edge; and a peel force of the sealing strip at the first edge is greater than a peel force of the sealing strip at the middle line. When the battery cell body has a tendency to rupture the sealing strip and subsequently detach from the packaging body, even if first line of protection at a side, close to the battery cell body, of the sealing strip is ruptured, a sealing is also reinforced at the first edge on a side, away from the battery cell body, of the sealing strip, which constructs second line of protection on the sealing strip, thereby solving a problem of safety risks caused by insufficient packaging strength.