Vacuum-Assisted Pouch Forming to Prevent Battery Sheet Cracks
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Solution Overview
Problem
The formation of cracks in the accommodation part of pouch-type batteries during the manufacturing process of secondary batteries, which affects the integrity and reliability of the battery.
Innovation Solution
A pouch forming device and method that involves seating a pouch sheet on a lower die with a forming groove, elongating the pouch sheet through vacuum, and pressing the elongated portion using a punch to form the accommodation part, while controlling the stripper and punch movements to reduce pressure and speed, thereby preventing cracks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the pouch sheet is pressed directly to form the accommodation part, then the forming process is simple, but cracks occur in the pouch sheet
Solution Approach 1:
The pouch sheet is elongated through vacuum suction before the punch presses it to form the accommodation part. This preliminary elongation prepares the material to accommodate the forming process without cracking, resolving the contradiction between simple forming and preventing cracks.
Solution Approach 2:
The vacuum suction applies a cushioning elongation effect to the pouch sheet before the pressing action. This pre-stretching cushions the material against the stress of subsequent forming, preventing crack formation while maintaining process simplicity.
2Reliability
If the pouch sheet is elongated through vacuum before forming, then cracks are prevented, but the process complexity increases
Solution Approach 1:
The vacuum elongation and punch forming operations are merged into a single integrated process. The lower die with vacuum passages and the punch work together in sequence without requiring separate equipment or complex intermediate steps, thus preventing cracks while minimizing process complexity.
Solution Approach 2:
The lower die serves multiple functions: it provides the forming groove for the accommodation part and simultaneously acts as a vacuum source through integrated vacuum passages. This multi-functionality eliminates the need for separate vacuum equipment, reducing overall process complexity while maintaining reliability.
3Productivity
If the punch presses the pouch sheet with high force, then the accommodation part is formed efficiently, but cracks occur in the pouch sheet
Solution Approach 1:
The pouch sheet is elongated through vacuum suction before the punch applies pressing force. This preliminary action prepares the material to withstand the subsequent high-force pressing without cracking, enabling both high productivity and reliability.
Solution Approach 2:
The process uses dynamic sequencing where vacuum suction is applied first to elongate the pouch sheet, then the punch presses with high force. This dynamic timing optimization allows efficient forming while preventing cracks through proper sequence control.
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
The method effectively prevents cracks in the pouch sheet during the formation of the accommodation part, improving the manufacturing process by enhancing elongation efficiency and reducing defects, leading to higher-quality pouch batteries.
Implementation Method 1
a vacuum unit, connected to the forming groove of the lower die, to elongate a forming portion of the pouch sheet through vacuum
Implementation Method 2
elongating the pouch sheet through vacuum
Data Source
Figure 1
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Figure 4
AI summary
Provided are a pouch forming method and a pouch forming device. The pouch forming method for forming an accommodation part accommodating an electrode assembly in a pouch sheet comprises a seating process of seating the pouch sheet on a top surface of a lower die in which a forming groove is formed in an upper portion thereof, a vacuum elongation process of elongating a lower portion of the pouch sheet, in which the accommodation part is formed, through vacuum, and an accommodation part formation process of pressing the portion of the pouch sheet, which is elongated through the vacuum, by using a punch disposed above the pouch sheet in a direction in which the forming groove is formed to form the accommodation part.