Pouch Cell Sealing Lines for Bendable Hermetic Battery Edges
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Solution Overview
Problem
Conventional pouch-type secondary batteries face challenges in sealing and bending due to uniformly thermally welded sealed portions, which makes it difficult to reduce the battery's volume and increase the risk of process errors and reduced sealability.
Innovation Solution
The battery cell features parallel and spaced sealed lines at the outer edge of the battery case, with non-welded or low-welded portions between them, allowing for easy bending and accurate formation of bent portions, reducing process errors and maintaining sealability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sealed portion is uniformly thermally welded to ensure hermetical sealability, then the sealing reliability is improved, but the difficulty of bending the sealed pouch increases
Solution Approach 1:
The sealed portion is divided into multiple sealed lines instead of being uniformly welded. The welding is segmented into first sealed lines, second sealed lines, and intermediate portions, where the intermediate portions have lower welding strength or are non-welded. This segmentation allows the sealed pouch to be bent at the intermediate portions while maintaining hermetic sealing at the sealed lines.
Solution Approach 2:
Different regions of the sealed portion are given different welding qualities. The first and second sealed lines have high welding strength for hermetic sealing, while the intermediate portions between them have lower welding strength or are non-welded to facilitate bending. This local differentiation of welding quality resolves the contradiction between sealing reliability and bendability.
2Stability of the object's composition
If the sealed portion is made rigid through uniform thermal welding, then the structural stability is improved, but the flexibility for volume reduction is worsened
Solution Approach 1:
The sealed portion is segmented into rigid sealed lines and flexible intermediate portions. The sealed lines provide structural stability and hermetic sealing, while the intermediate portions provide flexibility for bending and volume reduction. This segmentation allows the sealed pouch to maintain stability where needed while adapting its volume through bending at the intermediate portions.
Solution Approach 2:
Different regions of the sealed portion have different mechanical properties. The sealed lines have high rigidity for structural stability, while the intermediate portions have lower rigidity for flexibility. This local quality differentiation enables the sealed pouch to be bent for volume reduction while maintaining overall structural integrity.
3Volume of moving object
If additional bending processes are performed on the sealed pouch, then the volume reduction is improved, but the process complexity and error risk increase
Solution Approach 1:
The welding structure is preliminarily designed with first sealed lines, second sealed lines, and intermediate portions that are non-welded or have lower welding strength. This preliminary design of the welding pattern creates built-in bending zones that facilitate volume reduction through bending without requiring complex additional processes, thereby reducing process complexity and error risk.
4Ease of manufacture
If the sealed portion is uniformly welded, then the manufacturing simplicity is maintained, but the manufacturing precision for bending positions is worsened
Solution Approach 1:
The sealed portion is segmented into distinct sealed lines and intermediate portions with different welding characteristics. The sealed lines serve as precise reference markers for bending positions, while the intermediate portions are designed to be bent. This segmentation improves manufacturing precision for bending positions while maintaining manufacturing simplicity through a systematic welding pattern.
Solution Approach 2:
Different regions of the sealed portion have different welding qualities that serve specific functions. The sealed lines have high welding strength for precise positioning and hermetic sealing, while the intermediate portions have lower welding strength for bending. This local quality differentiation improves bending position accuracy without significantly complicating the manufacturing process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enables the battery cell to be easily bent, reducing volume and improving manufacturing accuracy, while maintaining airtightness and preventing electrolyte leakage.
Implementation Method 1
a sealed portion is formed at an outer edge of a receiving part, in which an electrode assembly is mounted, by thermal welding
Data Source
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AI summary
Disclosed herein is a battery cell configured to have a structure in which an electrode assembly is mounted in a battery case made of a laminate sheet including a resin layer and a metal layer, and the battery case is provided with a sealed portion (an outer edge sealed portion), which is formed at the outer edge of a receiving part, in which the electrode assembly is mounted, by thermal welding in order to seal the battery case, wherein electrode terminals are located at an upper sealed portion, a lower sealed portion, or the upper sealed portion and the lower sealed portion, two or more sealed lines are formed in at least one of side sealed portions, which are adjacent to the upper sealed portion or the lower sealed portion, such that the sealed lines are spaced apart from each other and parallel to each other, the sealed lines are continuously formed from the outer edge end of the upper sealed portion to the outer edge end of the lower sealed portion in the longitudinal direction of the battery case, and the outer edge sealed portion, in which the sealed lines are formed, is bent between the sealed lines at an angle of 30 to 180 degrees.