Pouch Battery Bridge Notch Structure to Prevent Bat-Ears
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Solution Overview
Problem
Pouch-type secondary batteries face issues with undesired deformation of the pouch film during the forming process, leading to potential damage of the electrode assembly and the formation of bat-ears, which affect energy density and assembly accuracy.
Innovation Solution
The introduction of a notch in the bridge portion of the pouch film, which acts as a hinge during folding, prevents collision with the electrode assembly and reduces bat-ear formation by providing a well-defined pouch structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pouch film is formed without a notch in the bridge portion, then the structure is simpler, but the pouch film deforms undesirably during folding and collides with the electrode assembly
Solution Approach 1:
A notch is formed in advance in the bridge portion of the pouch film before the folding process. This preliminary structural modification creates a predetermined folding line that guides the folding process, preventing the bridge portion from deforming undesirably and colliding with the electrode assembly during subsequent folding operations.
2Manufacturing precision
If the pouch film is formed without a notch, then the manufacturing process is simpler, but bat-ears are formed affecting energy density and assembly accuracy
Solution Approach 1:
The notch is created during the pouch film forming process as a preliminary structural feature. This advance preparation ensures that when folding occurs, the bridge portion follows the predetermined notch line, preventing bat-ear formation and ensuring high dimensional stability and assembly accuracy without requiring additional post-processing steps.
3Stability of the object's composition
If the bridge portion is made rigid to maintain structure, then dimensional stability improves, but deformation and crack risks increase during folding
Solution Approach 1:
The bridge portion of the pouch film is segmented by introducing a notch that divides it into distinct regions. This segmentation creates a controlled weakness at the notch location, allowing the bridge portion to flex and deform along the notch line during folding rather than cracking. The segmented structure maintains overall structural integrity while enabling necessary flexibility during the folding process.
Data Source
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AI summary
In a pouch-type battery case (10) which is configured to accommodate an electrode assembly (21) having a structure in which electrodes (23, 25) and separators (24) are alternately arranged, the battery case (10) comprises a pouch film (1) having a film thickness (d1), a first surface (31) and a second surface (34), a first cup portion (13) formed in the pouch film (1) having a recessed shape offset from the first surface (31) towards the second surface (34); a second cup portion (15) formed in the pouch film (1) having a recessed shape offset from the first surface (31) towards the second surface (34); and a bridge portion (14) formed in the pouch film (1) between the first cup portion (13) and the second cup portion (15) and connecting the first cup portion (13) to the second cup portion (15); the bridge portion (14) includes a notch (41) formed in the first surface (31) projecting towards the second surface (34).