Correction Roll Profile for Uniform Electrode Sheet Stretching
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Solution Overview
Problem
Electrode sheets with multiple non-formation portions experience strain due to differences in stretched length among these portions, leading to potential warping and defects during the rolling process.
Innovation Solution
A rolling apparatus and method that utilize a correction roll with short-diameter and long-diameter portions to adjust the stretched length of non-formation portions, ensuring uniform stretching and minimizing strain by varying the outer diameters of the long-diameter portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a stepped roll with uniform long-diameter portions is used to stretch non-formation portions, then the non-formation portions are stretched, but the difference in stretched length among multiple non-formation portions causes strain and warping
Solution Approach 1:
The correction roll has different long-diameter portions with different outer diameters corresponding to different non-formation portions. Each long-diameter portion is designed with a specific diameter to achieve the required stretched length for its corresponding non-formation portion, thereby eliminating strain and warping caused by uneven stretching.
Solution Approach 2:
The outer diameter of each long-diameter portion is adjusted as a parameter to control the stretched length of corresponding non-formation portions. By changing the outer diameter parameter of each long-diameter portion individually, the stretched length of each non-formation portion is precisely controlled to be substantially equal, preventing electrode sheet warping.
2Manufacturing precision
If pressing pressure is applied only to the active material-containing layer, then the active material layer is compressed, but the current collector exposed portion is not stretched sufficiently causing strain
Solution Approach 1:
The correction roll is segmented into different portions: short-diameter portions corresponding to active material layers and long-diameter portions corresponding to non-formation portions. This segmentation allows different functions to be performed on different parts of the electrode sheet simultaneously - compression on active material layers and stretching on non-formation portions.
Solution Approach 2:
The correction roll combines both compression and stretching functions in a single device. By positioning the correction roll to contact both the active material-containing layer and the current collector exposed portion, it simultaneously compresses the active material layer while stretching the non-formation portions, eliminating strain without requiring separate processing steps.
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 solution effectively suppresses the difference in stretched length among non-formation portions, reducing strain and warping of the electrode sheet, thereby improving the rolling process efficiency and product quality.
Implementation Method 1
a tensile force applied in a transportation direction of the band-like electrode plate may be concentrated on the current collector exposed portion. As a result, the current collector exposed portion may be stretched
Implementation Method 2
a pair of press rolls located on the transportation path along which the electrode sheet is transported by the transportation device, the pair of press rolls sandwiching the electrode sheet to press the active material layer
Data Source
AI summary
A rolling apparatus includes a transportation device transporting an electrode sheet along a predefined transportation path; a pair of press rolls located on the transportation path and pressing an active material layer of the electrode sheet; and a correction roll located upstream or downstream with respect to the pair of press rolls. The correction roll includes at least one short-diameter portion each provided at a position corresponding to the active material layer in the width direction of the electrode sheet, and a plurality of long-diameter portions each having an outer diameter longer than an outer diameter of the short-diameter portion, non-formation portions of the electrode sheet being respectively wound along the plurality of long-diameter portions. The plurality of long-diameter portions includes a first long-diameter portion, and a second long-diameter portion, the outer diameter of which is longer than the outer diameter of the first long-diameter portion.