Two-Step Sealing for Pouch Battery Side Portions
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Solution Overview
Problem
Pouch-shaped batteries with a single member bent portion face issues where the sealant layer is pushed out, forming a 'bat ear' during sealing, leading to increased measured length and reduced capacity due to inefficient sealing processes in existing technologies.
Innovation Solution
A two-step sealing method is employed, where the lower end part of the side portion adjacent to the bent portion is sealed in the primary step, and the entirety of the side portion is sealed in the secondary step, using different shaped sealing blocks for each step to minimize the bat ear formation and ensure precise measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single member bent portion is sealed in one step, then the sealing process is simple and fast, but the sealant layer is pushed out forming a bat ear that increases measured length and reduces capacity
Solution Approach 1:
The sealing process is divided into two distinct steps: a first sealing step that seals the side portion from the outer edge toward the bent portion, and a second sealing step that seals the bent portion. This segmentation prevents the sealant layer from being pushed out during sealing, eliminating the bat ear formation while maintaining process efficiency.
Solution Approach 2:
The first sealing step is performed as a preliminary action before the second sealing step. By pre-sealing the side portion adjacent to the bent portion, the structure is prepared to prevent sealant push-out during the subsequent bending and final sealing operations.
2Stability of the object's composition
If the entirety of the bent end is sealed, then wrinkles are prevented, but the volume of the battery cell is reduced
Solution Approach 1:
Different sealing approaches are applied to different regions: the side portion adjacent to the bent portion is sealed in the first step with controlled pressure and temperature to prevent wrinkle formation, while the bent portion itself is sealed in the second step with parameters optimized to minimize volume reduction. This local quality differentiation resolves the contradiction between wrinkle prevention and volume preservation.
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 method significantly reduces the length of the bat ear, minimizing waste and allowing for precise measurement of the battery cell length, thereby increasing the overall capacity and reducing the measured length of the battery cell.
Implementation Method 1
a thermal-fusion sealing process is performed in order to seal a pouch-shaped battery cell
Implementation Method 2
the upper case and the lower case, which are adhered via pressure being applied to adhesive resin layers
Data Source
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AI summary
Disclosed herein is a method of sealing a side portion of a pouch-shaped battery including an electrode current collector and a pouch-shaped battery case, the method including bending a lower case and an upper case connected to the lower case in the state in which the electrode current collector is mounted in the lower case such that the upper case faces the lower case, a primary sealing step for sealing the lower end part of a side portion of the pouch-shaped battery case adjacent to the outer edge of the pouch-shaped battery case in the direction of protrusion of an electrode terminal, which is connected to the bent portion of the pouch-shaped battery case, in the state in which the upper case faces the lower case, and a secondary sealing step for sealing the entirety of the side portion of the pouch-shaped battery case.