Secondary Battery Pouch Bridge Geometry for Bat-Ear Wrinkle Control
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Solution Overview
Problem
The manufacturing of pouch-type secondary batteries often results in wrinkles, specifically bat-ear shaped wrinkles, when the battery case is folded, which reduces capacity and increases the risk of cracks and damage.
Innovation Solution
A method involving a pouch sheet with bilaterally symmetrical accommodation grooves and a bridge connecting them, where the bridge protrudes upward and has a rounded upper end, is used to optimize the folding process, preventing or minimizing wrinkles by ensuring proper alignment and sealing of the electrode assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the pouch is folded to manufacture the secondary battery, then the battery can be assembled in a compact form, but wrinkles having a bat-ear shape occur on the folded portion
Solution Approach 1:
The patent applies preliminary action by pre-forming accommodation grooves and a bridge structure on the pouch sheet before the folding operation. The grooves are positioned to receive the electrode assembly, and the bridge connects these grooves to provide structural support during folding, preventing wrinkles from forming on the folded portion while maintaining compact assembly capability
2Quantity of substance
If the pouch is folded to increase battery capacity, then more electrode assembly can be accommodated, but wrinkles and cracks occur reducing structural integrity
Solution Approach 1:
The patent applies segmentation by dividing the pouch sheet into distinct functional zones: accommodation grooves that receive the electrode assembly and a bridge structure that connects these grooves. This segmentation allows the pouch to be folded to increase capacity while the bridge structure maintains structural integrity and prevents crack formation along the fold lines
3Ease of manufacture
If the pouch is folded without proper structural support, then manufacturing is simpler, but wrinkles and cracks occur increasing the risk of damage
Solution Approach 1:
The patent applies local quality by providing structural support (the bridge connecting the accommodation grooves) only at the specific locations where wrinkles and cracks are most likely to occur during folding. This localized reinforcement maintains ease of manufacture while preventing harmful defects on the folded portion
Data Source
AI summary
A method for manufacturing a secondary battery includes a forming step of pressing a pouch sheet by using a press die so that left and right accommodation grooves, which are bilaterally symmetrical to each other and are opened upward, and a bridge connecting the left and right accommodation grooves to each other are formed in the pouch sheet, wherein the bridge protrudes upward with respect to bottom surfaces of the left and right accommodation grooves, and a curved portion having a rounded shape is formed on an upper end of the bridge, a seating step of seating an electrode assembly in one of the left and right accommodation grooves, and a folding step of folding the pouch sheet so that the left and right accommodation grooves face each other.