Battery Winding Separator Adhesion Pattern to Prevent Wrinkles
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Solution Overview
Problem
The existing methods for manufacturing storage devices with wound electrode bodies face challenges in productivity due to issues like distortion, wrinkles, or winding deviations caused by the adhesion between the separator and electrodes, especially when using adhesive resins.
Innovation Solution
A method involving a separator with an adhesion layer arranged in a dot pattern, where each dot has a central non-adhesive region, is used for winding and pressing steps to control the adhesion and reduce the non-adhesive area to 1/2 or less, ensuring proper positional alignment and minimizing distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the separator includes adhesive resin to firmly adhere to electrodes, then adhesion strength is improved, but distortion and wrinkles occur in the separator during pressing
Solution Approach 1:
The adhesion layer is segmented into dot-shaped regions distributed across the separator surface, rather than forming a continuous layer. Each dot has a non-formed region in its center, creating discrete adhesion points that allow localized flexibility while maintaining overall adhesion. This segmentation prevents the separator from developing large-area distortions and wrinkles during pressing, while still providing sufficient adhesion strength.
Solution Approach 2:
The separator exhibits spatially varying properties: dot-shaped adhesion regions provide strong bonding capability at specific locations, while the non-formed central regions and inter-dot areas maintain flexibility and conformability. This local differentiation allows the separator to adhere firmly to electrodes at contact points while accommodating dimensional changes and preventing wrinkle formation in non-adhesive regions.
2Strength
If the adhesion layer non-formed region area is not reduced during pressing, then flexibility is maintained, but adhesion strength is insufficient
Solution Approach 1:
The pressing process induces dimensional changes in the dot-shaped adhesion layers, causing the non-formed central regions to expand and reduce the overall adhesion area. This parameter change during pressing automatically adjusts the adhesion characteristics: initial dot shapes provide strong adhesion during winding, while pressed configuration with reduced non-formed region area provides optimized adhesion for the final flat wound electrode body, preventing both excessive adhesion (wrinkles) and insufficient adhesion (winding deviation).
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
This approach enhances productivity by preventing distortions and winding deviations, allowing for the efficient formation of high-quality flat wound electrode bodies with improved adhesion during the pressing step.
Implementation Method 1
a separator including an adhesion layer arranged in a shape of a plurality of dots on at least one surface of the separator
Data Source
Figure 1~2
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Figure 6~8
AI summary
A method for manufacturing a storage device (100) disclosed herein includes a winding step (S3) of winding a positive electrode (22) and a negative electrode (24) with a separator (26) interposed therebetween to manufacture a wound body (20A), and a pressing step (S4) of pressing the wound body (20A) to form the wound body (20A) into a flat wound electrode body (20a). In the winding step (S3), a separator (26) including an adhesion layer (6) arranged in a shape of a plurality of dots is used. Each of the dots of the adhesion layer (6) includes an adhesion layer non-formed region (E) in a central portion thereof when viewed from top. In the pressing step (S4), an area of the adhesion layer non-formed region (E) when viewed from top is reduced to 1/2 or less.