Wound Electrode Separator Adhesion Pattern for Flat Cell Assembly
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Solution Overview
Problem
The manufacturing of storage devices with wound electrode bodies faces challenges in productivity due to issues such as distortion, wrinkle formation, and winding deviation caused by the adhesion between the separator and electrodes, especially when using adhesive resin, which affects the positional relationship and winding accuracy.
Innovation Solution
A method involving a separator with an adhesion layer arranged in a dot shape, where each dot has a central non-adhesive region, is used in the winding process, allowing for controlled adhesion during the pressing step to reduce the non-adhesive area to half or less, ensuring proper positional alignment and minimizing distortion and winding deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive resin is used to firmly adhere the separator and electrodes, then adhesion strength is improved, but distortion and wrinkle occur in the separator during pressing
Solution Approach 1:
The adhesion layer is configured with spatially varying properties: the outer peripheral region has adhesive resin for strong bonding, while the central region has reduced adhesion to allow deformation during pressing. This local differentiation resolves the contradiction by providing strong adhesion where needed while preventing wrinkle formation in the central area.
Solution Approach 2:
The adhesion layer is segmented into functionally distinct regions: an outer peripheral region for adhesion and a central region for deformation accommodation. This segmentation allows each region to perform its specific function independently, resolving the conflict between adhesion strength and separator flatness.
2Strength
If adhesive resin is used to firmly adhere the separator and electrodes, then adhesion strength is improved, but winding deviation occurs
Solution Approach 1:
The adhesion layer provides strong bonding at the outer peripheral regions where winding stability is critical, while the central region's reduced adhesion allows the separator to deform and absorb winding deviations without transferring them to the electrode assembly, thereby maintaining winding accuracy.
3Manufacturing precision
If the separator does not include adhesive resin, then distortion and wrinkle are reduced, but winding deviation occurs
Solution Approach 1:
Rather than uniformly applying adhesive resin, the invention applies it only to the outer peripheral region where winding stability is needed. The central region remains free of adhesive resin, allowing the separator to deform freely during pressing without causing winding deviation, thus achieving both flatness and winding accuracy.
4Strength
If adhesive resin is used to firmly adhere the separator and electrodes, then adhesion strength is improved, but productivity is reduced
Solution Approach 1:
The adhesion layer is applied only to the outer peripheral region rather than the entire separator surface. This localized application reduces the amount of adhesive resin needed, shortens the drying time, and decreases the pressing time required, thereby improving manufacturing efficiency while maintaining sufficient adhesion strength.
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 the productivity of storage devices by maintaining the positional integrity of the separator and electrodes, reducing distortion and winding deviations, thereby improving the manufacturing efficiency and quality of the wound electrode bodies.
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
AI summary
A method for manufacturing a storage device disclosed herein includes a winding step of winding a positive electrode and a negative electrode with a separator interposed therebetween to manufacture a wound body, and a pressing step of pressing the wound body to form the wound body into a flat wound electrode body. In the winding step, a separator including an adhesion layer arranged in a shape of a plurality of dots is used. Each of the dots of the adhesion layer includes an adhesion layer non-formed region in a central portion thereof when viewed from top. In the pressing step, an area of the adhesion layer non-formed region when viewed from top is reduced to ½ or less.