Curved Pouch Battery Cell Sealing for Electrolyte Leak Prevention
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Solution Overview
Problem
The issue of non-uniform sealing width and electrolyte leakage in the both-sided face sealing parts of curved battery cells, particularly pouch-type secondary batteries, due to their curved shape, which leads to potential moisture permeation and electrolyte leakage.
Innovation Solution
A battery cell design with a curved cross-section where both side ends are bent together, featuring a cutting part formed within 1/3 to 2/3 of the total length of the sealing parts, sealed with UV glue coating, and a UV curable material applied on the cutting surface to enhance sealing strength and prevent leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the battery cell is formed with a curved cross-section where both side ends are bent together, then the battery can be miniaturized and thinned to fit electronic devices, but the sealing width in the both-sided face sealing parts becomes non-uniform
Solution Approach 1:
The both-sided face sealing parts are divided into multiple sealing regions along the curved surface. By segmenting the sealing structure, each region can maintain adequate sealing width despite the overall curvature, preventing non-uniform sealing across the entire face.
Solution Approach 2:
The sealing structure is designed with locally optimized features where the sealing width is enhanced at critical curved regions. This allows the sealing quality to be maintained specifically where needed most, rather than requiring uniform thickness throughout the entire battery case.
2Adaptability or versatility
If the both-sided face sealing parts are bent toward the battery cell to achieve curved shape, then the battery can be deformed to various shapes, but the sealing width cannot be secured consistently
Solution Approach 1:
The sealing parts are pre-formed with built-in reinforcement structures and optimized geometry before the bending process. This preliminary preparation ensures that when the battery is deformed into various shapes, the sealing width remains consistent throughout the bending operation.
Solution Approach 2:
The sealing structures incorporate curved and rounded geometries that naturally distribute stress and maintain uniform sealing width during bending. By designing the sealing parts with appropriate curvature radii, the battery can be deformed while preserving sealing consistency.
3Ease of manufacture
If heat-sealing is used to seal the pouch-type battery case, then the manufacturing process is simple, but contamination occurs, excessive melting happens, and the inner resin layer protrudes causing leakage
Solution Approach 1:
The traditional heat-sealing process is replaced with a mechanical sealing method using a crimping structure. This mechanical approach applies controlled pressure and deformation to create a reliable seal without the thermal effects that cause contamination, excessive melting, and resin layer protrusion.
Solution Approach 2:
The sealing structure utilizes a composite design combining the pouch-type battery case with a separate crimping component. This composite structure enables reliable sealing through mechanical action while protecting the laminated sheet structure from thermal damage.
4Productivity
If the inner resin layer protrudes to the outside due to pressurization during heat-sealing, then the sealing process completes, but moisture permeation and electrolyte leakage occur
Solution Approach 1:
The heat-sealing process that causes resin layer protrusion is replaced with a mechanical crimping process. This mechanical sealing method applies controlled pressure to compress and seal the edges without generating the excessive heat and pressure that force the inner resin layer outward, thereby preventing moisture permeation and electrolyte leakage.
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
Secures consistent sealing width and prevents electrolyte leakage and moisture penetration, while improving sealing strength and reducing stress concentration, thus enhancing the safety and capacity of the battery cell.
Implementation Method 1
a UV curable material is cured to form a sealing coating on the cutting surface
Data Source
Figure 1
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Figure 3~4
AI summary
The present disclosure relates to a battery cell that has a curved shape so that its cross section has a curve, wherein both-sided face sealing parts of a battery case are sealed by UV glue coating based on the direction in which electrode leads are formed, and a cutting part is formed at a central part in the longitudinal direction of each of the both-sided face sealing parts.