Pouch Battery Sealing Gap to Prevent Temporary Attachment
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Solution Overview
Problem
Conventional pouch-type secondary batteries face issues with the formation of temporary attachment portions in temporary attachment regions during the sealing process, particularly in top sealing, which can lead to poor insulation and exposure of metal layers to electrolytes due to the breakdown of these regions under increased internal pressure.
Innovation Solution
A manufacturing method and device that forms an up-and-down gap in the temporary attachment region between the pouches, preventing the formation of temporary attachment portions by maintaining a separation between the upper and lower pouches during the sealing process, especially in the top sealing region, using suction nozzles to maintain this gap.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the pouches are heat-fused by pressurizing the sealing region, then the sealing strength is improved, but temporary attachment portions are formed in the temporary attachment region
Solution Approach 1:
The pouch surface is divided into distinct regions: a sealing region where pressurization is applied to form strong seals, and a temporary attachment region where no pressurization occurs, preventing temporary attachment portion formation. This spatial segmentation allows the sealing region to provide strong bonding while the temporary attachment region maintains insulation reliability.
Solution Approach 2:
Different regions of the pouch are given different functional properties: the sealing region is designed to be pressurized and bonded, while the temporary attachment region is kept free from pressurization to prevent unwanted attachment. This local differentiation of quality ensures that sealing strength is enhanced where needed without compromising insulation reliability elsewhere.
2Strength
If the polypropylene film is melted and spread during heat fusion, then the bonding between pouches is improved, but the metal layer becomes exposed to electrolyte
Solution Approach 1:
The pouch structure is segmented into a sealing region where the polypropylene film melts and bonds the metal layers together, and a temporary attachment region where the film remains intact to continue protecting the metal layer from electrolyte exposure. This segmentation allows bonding strength to be improved in the sealing region while preventing metal layer corrosion in the temporary attachment region.
3Reliability
If the pouch is heat-pressurized to form sealing portion, then the sealing function is improved, but temporary attachment portions form between pouches
Solution Approach 1:
The pouch is divided into a sealing region where heat pressurization creates reliable seals and a temporary attachment region where the pouch structure remains unchanged, maintaining proper spacing and preventing unwanted attachment between pouches. This segmentation preserves pouch structure integrity while improving sealing function.
Solution Approach 2:
Heat pressurization is applied locally only to the sealing region, giving that area enhanced sealing properties while leaving the temporary attachment region with its original structural properties intact. This local quality differentiation ensures sealing function is improved without compromising pouch structure integrity.
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
Effectively prevents the formation of temporary attachment portions, enhancing insulation and reducing the risk of metal layer exposure, while being compatible with conventional manufacturing processes without additional steps.
Implementation Method 1
a suction step of sucking the upper pouch to the upside and sucking the lower pouch to the downside in the temporary attachment region through a suction nozzle
Implementation Method 2
the inner insulating coating layer (1a) in the sealing region is melted by heat pressurization to form a sealing portion (6)
Implementation Method 3
heat-pressurizing the pouch through a sealing tool (2)
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
According to one example of the present invention, a pouch-type secondary battery manufacturing method, which is characterized in that the method comprises a forming step of sinking a partial region of a pouch to form an accommodation portion in which an electrode assembly is seated; an introduction step of seating the electrode assembly within the accommodation portion; and a sealing step of pressurizing a sealing region spaced apart from the edge of the accommodation portion by a predetermined distance at the outer side of the accommodation portion to form a sealing portion between an upper pouch and a lower pouch as laminated, and at least some sections of the sealing step are performed in a state where an up-and-down gap is maintained between the upper and lower pouches laminated in a temporary attachment region located between the edge of the accommodation portion and the sealing region, and a pouch-type secondary battery manufactured therethrough may be provided.