Pouch Battery Case Die-Edge Curvature for Tab-Safe Molding
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Solution Overview
Problem
The interference between the die edge and the electrode tab occurs during the molding process of pouch type secondary batteries, which affects the moldability and integrity of the battery case.
Innovation Solution
The battery case design includes die edges with varying curvature radii to accommodate the electrode tab, and the pouch film is composed of specific layers with optimized thickness and composition to enhance moldability and prevent interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the moisture barrier layer is improved in moldability to make the wall of the cup part close to a vertical state and improve the curvature radius of the edge of the cup part, then the moldability is improved, but the die edge presses the electrode tabs to cause interference
Solution Approach 1:
The die edge is designed with different curvature radii at different locations: a first curvature radius in the region that contacts the electrode tab and a second curvature radius (smaller than the first) in other regions. This local differentiation allows the die edge to provide adequate support to the electrode tab while maintaining vertical wall formation and edge curvature improvement in non-contact regions, thus resolving the interference issue while preserving moldability improvements
2Manufacturing precision
If the curvature radius of the die edge is reduced to improve moldability, then the moldability is improved, but the die edge interferes with the electrode tab
Solution Approach 1:
The die edge curvature radius is locally optimized by setting a first curvature radius in the electrode tab contact region and a second (smaller) curvature radius in other regions. This ensures that the electrode tab region maintains sufficient curvature to prevent interference and damage, while other regions can achieve smaller curvature radii for improved moldability and vertical wall formation
3Ease of manufacture
If the wall of the cup part is made close to a vertical state to improve moldability, then the moldability is improved, but the die edge presses the electrode tabs causing interference
Solution Approach 1:
The die edge geometry is locally differentiated with a first curvature radius in the electrode tab contact region and a second curvature radius in other regions. This allows the cup part wall to be formed close to a vertical state for improved moldability, while the electrode tab contact region maintains adequate curvature to prevent die edge interference with the electrode tabs
Data Source
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AI summary
Provided is a pouch type battery case. The pouch type battery case include a cup part configured to accommodate an electrode assembly, which is formed by stacking electrodes and separators, therein and a plurality of die edges configured to connect an wall of the cup part to a side extending from the wall. At least one die edge includes a first area formed to be rounded with a first curvature radius and a second area formed to be rounded with a second curvature radius less than the first curvature radius.