Electrode Assembly Sealing with Downward Separator Bending
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Solution Overview
Problem
The separator wrinkling phenomenon occurs during the sealing process of pouch-type secondary batteries, leading to insulation failure due to the interference of the separator with the battery case, which is exacerbated by the melting of the binder component and inner coating layer, causing cracks and damage.
Innovation Solution
A manufacturing method and device that control the heat-sealing direction of the separator to be downward, using a transfer unit, sealing blocks, and lower supports to ensure the separator is bent and sealed in a consistent direction, preventing wrinkling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the separator is heat-sealed in an upwardly bent state during conventional sealing, then the separator can be sealed to the battery case, but the separator wrinkles during sealing causing interference with the battery case
Solution Approach 1:
The patent inverts the conventional sealing approach by sealing the separator in a downwardly bent state rather than upwardly bent. The sealing member presses the downwardly bent separator end against the battery case, creating a sealed state that prevents wrinkling during the sealing process while maintaining sealing integrity.
Solution Approach 2:
The patent applies preliminary action by pre-bending the separator end in the downward direction before the sealing process begins. This preliminary bending ensures that during sealing, the separator follows the intended path and does not wrinkle, as the bending direction is established prior to contact with the sealing member.
2Reliability
If high temperature pressurization is applied to seal the battery case, then the inner coating layer melts and bonds the battery case layers, but the binder component of the separator also melts causing separator wrinkling
Solution Approach 1:
The patent applies local quality by making the separator end portion have different properties from the rest of the separator. The separator end is designed to be bent downward and sealed in a specific configuration, creating a localized structural difference that prevents the harmful wrinkling effect during high-temperature sealing while maintaining the bonding function.
3Reliability
If the separator protrudes from the electrode assembly to cover the entire surface, then electrode coverage is ensured, but the separator interferes with the battery case sealing area
Solution Approach 1:
The patent applies segmentation by dividing the separator into two functional zones: the main body that covers the electrode surface and the end portion that is bent downward for sealing. This segmentation allows the separator to fulfill both functions - providing adequate electrode coverage while the segmented end portion is directed away from the sealing area to prevent interference.
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
Prevents separator wrinkling during the sealing of pouch-type battery cases, ensuring the integrity of the battery case and preventing insulation failure.
Implementation Method 1
seal the ends of multiple separators by heating and pressing
Implementation Method 2
heat-seals the separator by heating the end of the separator S
Implementation Method 3
both distal ends of multiple separators in the longitudinal direction are bent downward and sealed while contacting the sealing block
Implementation Method 4
the inner coating layer of the corresponding area is melted and the two layers of the battery case are heat-sealed
Data Source
Figure 1~2
Figure 3
Figure 4(a)~4(c)
AI summary
An electrode assembly manufacturing device according to the present disclosure includes a transfer unit for transferring an electrode assembly to a sealing position, multiple sealing blocks, and a lower support. The lower support is controlled to move up and down in a first state in which the sealing block is moved forward toward the electrode assembly, so that both distal ends of multiple separators in the longitudinal direction are bent downward and sealed while being in contact with the sealing block. Since the electrode assembly manufacturing device according to embodiments of the present invention heat-seals the end of the separator in a downwardly bent state, it is possible to manufacture an electrode assembly that prevents blocking of the separator when sealing a pouch.