Pouch Cell Case Bending to Prevent Bat-Ear Deformation
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Solution Overview
Problem
Morphological deformation of pouch-type battery cells occurs due to residual stress during the manufacturing process, particularly at the bat-ear portion, leading to undesirable shape deviations.
Innovation Solution
A manufacturing method where the pouch case is bent based on an edge line adjacent to the recessed portion's edge, minimizing residual stress and preventing bat-ear formation by integrating the bending line with the recessed portion's edge, ensuring a designed shape is maintained.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the pouch case is bent based on a bending line spaced apart from the edge line of the recessed portion, then the recessed portion can be formed, but residual stress causes deformation and bat-ear portions
Solution Approach 1:
The pouch case is pre-formed with a recessed portion before the bending operation. By preparing the recessed portion in advance and then bending the pouch case based on the edge line of this pre-formed recessed portion, the method eliminates residual stress accumulation that would otherwise occur when forming the recessed portion during bending. This preliminary action prevents the bat-ear portion deformation while maintaining manufacturing efficiency.
2Ease of manufacture
If the bending line is formed spaced apart from the edge line, then the recessed portion structure can be created, but the folded portion forms a protruding bat-ear portion
Solution Approach 1:
The bending line is merged with the edge line of the recessed portion, eliminating the spacing between them. This integration ensures that when the pouch case is bent, the folded portion aligns precisely with the recessed portion edge, preventing the formation of protruding bat-ear portions while maintaining the structural integrity and ease of manufacture of the recessed portion.
3Adaptability or versatility
If draw forming is applied to create the recessed portion, then the electrode assembly can be housed, but residual stress causes morphological deformation
Solution Approach 1:
The recessed portion is formed in advance using draw forming before the bending operation. This preliminary formation allows the pouch case to be pre-adapted to house the electrode assembly while maintaining material integrity. By separating the recessed portion formation from the bending operation and using the pre-formed structure as the basis for bending, residual stress is eliminated and morphological deformation is prevented.
Data Source
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AI summary
A battery cell according to one embodiment of the present disclosure includes an electrode assembly including a positive electrode, a negative electrode, and a separator; and a pouch case in which a recessed portion for housing the electrode assembly is formed, wherein the pouch case is bent on the basis of at least one edge line among the edges formed by the recessed portion.