Stepped Roll Pressing for Wrinkle-Free Electrode Sheet Boundaries
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Wrinkles occur in electrode sheets during the manufacturing process due to differences in elongation rates between the uncoated and coated portions of the current collector, leading to issues in forming tabs and potential breakage.
Innovation Solution
A manufacturing apparatus and method that includes a first pressing step using rubber rolls to stretch uncoated portions, followed by a stepped roll pressing step to stretch boundary regions with larger diameters, and a final step to adjust the active material layer density, using a conveyor, first and second pressing devices, and a stepped roll with specific diameter configurations to manage elongation differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the uncoated portion is pressed by a pair of elastic rolls during roll-pressing, then compressive force and deformation force can be applied to prevent breakage, but wrinkles may occur in the electrode sheet due to difference in elongation rate between boundary region and other regions
Solution Approach 1:
The stepped roll has different diameters at different locations: a larger diameter at the boundary region between uncoated and coated portions, and a smaller diameter at other uncoated portions. This local variation in geometry allows differential pressing force distribution, applying stronger compression at the boundary region to prevent wrinkles while maintaining adequate breakage prevention across the entire uncoated portion.
Solution Approach 2:
The pressing operation is divided into two distinct stages: first pressing the uncoated portion with elastic rolls to prevent breakage, then pressing the boundary region with the stepped roll to eliminate wrinkles. This segmentation of the pressing process allows each stage to address specific problems without causing adverse effects.
2Device complexity
If uniform pressing is applied across the entire electrode sheet, then processing simplicity is maintained, but wrinkle formation occurs due to differential elongation between boundary and non-boundary regions
Solution Approach 1:
Instead of uniform pressing, the stepped roll implements local quality by having different diameters at different positions. The larger diameter portion contacts the boundary region to apply targeted pressing force where wrinkles form, while the smaller diameter portion contacts other uncoated regions. This resolves the wrinkle issue without requiring complex multi-stage pressing equipment.
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 reduces wrinkles and prevents breakage by uniformly stretching the electrode sheet, ensuring proper tab formation and reducing strain at boundary regions.
Implementation Method 1
press-stretching the unformed portion of the electrode sheet by a rubber roll
Implementation Method 2
pressing the electrode sheet onto a stepped roll including a stepped portion at a part coming into contact with a boundary region
Implementation Method 3
press-stretching the active material layer of the electrode sheet by roll-pressing
Data Source
AI summary
A method of method of manufacturing an electrode sheet includes: a first pressing step of press-stretching an uncoated portion of the electrode sheet by a rubber roll while conveying the electrode sheet along a predetermined conveyance passage, a stepped roll pressing step of, after the first pressing step, conveying the electrode sheet while pressing the electrode sheet onto a stepped roll including a stepped portion at a part of the stepped roll coming into contact with a boundary region of the uncoated portion with an active material layer, the part coming into contact with the unformed portion having a larger diameter than other parts of the stepped roll coming into contact with the active material layer; and a second pressing step of, after the stepped roll pressing step, press-stretching the active material layer of the electrode sheet by roll-pressing.