Electrode Assembly Tape Design for Uniform Pressure Distribution
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Solution Overview
Problem
Conventional secondary batteries face issues with nonuniform pressure distribution due to overlapping fixing tapes, leading to obstructed gas discharge and reduced safety during the activation process.
Innovation Solution
The electrode assembly incorporates non-overlapping and overlapping tape portions with a tapered structure, where the non-overlapping portions have a larger width than the overlapping portions, reducing the area of overlap to 1% to 20% of the total tape area, and using polyimide tapes for improved adhesion and pressure distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If tapes are used to fix the exterior of the electrode assembly, then the structural integrity is improved, but nonuniform pressure distribution occurs due to overlapping portions
Solution Approach 1:
The tape is divided into multiple segments: a first tape portion and a second tape portion, where the second tape portion is positioned to overlap the first tape portion. This segmentation allows the overlapping region to be specifically designed with reduced width, distributing the fixing function across different regions with different characteristics.
Solution Approach 2:
Different portions of the tape structure are given different qualities: the non-overlapping portions have larger width for strong fixing, while the overlapping portion has reduced width (1% to 20% of total tape area) to minimize pressure concentration. This local differentiation resolves the contradiction between maintaining structural integrity and ensuring uniform pressure distribution.
2Strength
If overlapping tape portions are used for fixing, then the adhesion strength is improved, but gas discharge is obstructed due to high applied pressure at overlap areas
Solution Approach 1:
The tape structure is segmented into overlapping and non-overlapping portions, allowing the adhesion function to be primarily fulfilled by the non-overlapping portions while the overlapping portion is minimized to avoid gas discharge obstruction.
Solution Approach 2:
The overlapping portion is designed with locally reduced width (1% to 20% of total tape area), creating a local quality difference that maintains adhesion strength where needed while minimizing pressure concentration that would obstruct gas discharge in critical areas.
3Strength
If the width of overlapping tape portions is large, then the fixing strength is improved, but the area of nonuniform pressure increases
Solution Approach 1:
The tape design implements local quality differentiation where the overlapping portion has significantly reduced width compared to the non-overlapping portions. This ensures that the overlapping area (which creates nonuniform pressure) is minimized to 1% to 20% of the total tape area, while the non-overlapping portions maintain sufficient width for strong fixing.
Solution Approach 2:
The tape is segmented into functional zones: non-overlapping portions that provide the majority of fixing strength over large areas, and a minimized overlapping portion that connects these zones while contributing minimal pressure nonuniformity.
Data Source
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AI summary
The present disclosure provides an electrode assembly comprising: a laminate body including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, and one or more pairs of tapes for fixing the exterior of the laminate body, wherein the pair of tapes includes non-overlapping portions that do not overlap with each other, and overlapping portions that overlap with each other, and wherein a width of the non-overlapping portions is larger than a width of the overlapping portions, and a secondary battery comprising the same.