Pouch Cell Folded Sealing Structure for Compact Module Assembly
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Solution Overview
Problem
Pouch-type secondary batteries face issues with energy density reduction due to protruding sealing parts, increased volume, and defective appearances, along with fluttering, bending, and detaching phenomena of folding parts, which hinder efficient heat dissipation and module assembly.
Innovation Solution
The design involves folding the sealing parts to ensure they do not protrude from the electrode assembly, using a polyurethane adhesive to attach the folding parts to the case, with specific dimensions and adhesive properties to prevent fluttering and ensure secure adhesion, thereby improving energy density and reducing volume and appearance issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sealing parts are formed by sealing the outermost portions of the case, then the battery is properly sealed and protected, but the total volume increases and energy density decreases
Solution Approach 1:
The sealing parts are folded back along the outer periphery of the electrode assembly in a dimensional transformation, changing from a protruding configuration to a folded configuration that follows the contour of the electrode assembly, thereby reducing overall volume while maintaining sealing function
Solution Approach 2:
The folded sealing parts are positioned to follow and nest along the outer periphery of the electrode assembly, with the folded sealing part having a length that does not exceed the length of the electrode assembly in the folding direction, creating a compact nested structure
2Reliability
If sealing parts protrude from the electrode assembly, then sealing is achieved, but heat dissipation is inhibited
Solution Approach 1:
The sealing parts are folded back to follow the outer periphery of the electrode assembly rather than protruding outward, creating a contour-following structure that maintains thermal contact between the electrode assembly and cooling plates while preserving sealing integrity
3Ease of manufacture
If folding parts are not properly secured, then assembly is simple, but fluttering, bending, and twisting phenomena occur
Solution Approach 1:
An adhesive member is applied in advance to the folded sealing part before final assembly, pre-securing the folding part to prevent fluttering, bending, and twisting phenomena during operation while maintaining relatively simple assembly procedures
4Stability of the object's composition
If adhesive member is applied extensively to secure folding parts, then stability is improved, but manufacturing complexity increases
Solution Approach 1:
The adhesive member is applied locally at specific positions on the folded sealing part rather than extensively across the entire surface, providing sufficient stability to prevent fluttering and twisting while minimizing manufacturing complexity and adhesive material usage
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 approach enhances energy density, prevents fluttering and detaching of folding parts, and improves heat dissipation by ensuring the folding parts are securely attached, resulting in a more efficient and compact secondary battery module.
Implementation Method 1
a folding part formed by folding sealing parts of surfaces on which the electrode tab drawn to an outside of the case is not formed; An adhesive member is applied to the folding part
Data Source
AI summary
An embodiment of the present invention relates to a pouch-type secondary battery. According to embodiment of the present invention, the pouch-type secondary battery includes: an case configured to house an electrode assembly from which electrode tab are drawn out; sealing parts formed by adhering the case along outer peripheries of the electrode assembly; and folding parts formed by folding the sealing parts of surfaces on which the electrode tab drawn to an outside of the case is not formed, wherein a length of the folding part has a relationship with a thickness of the electrode assembly as the following equation: H≤T/2 (wherein, H is the height of the folded folding part, T is the thickness of the electrode assembly, based on a cross-section perpendicular to a direction in which the electrode tabs of the electrode assembly are drawn out).