Electrode Sheet Folding Line for Accurate Tab Bending

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Solution Overview

Problem

The challenge in forming electrochemical cells is ensuring that electrode sheets are reliably and consistently folded at the desired zones to prevent short circuits and ensure proper electrode alignment, as existing methods often result in unintended folding of electrode sheet portions not affected by tabs.

Innovation Solution

Structurally weakening the electrode sheet along a longitudinal path creates a preferential folding line, allowing tabs to be easily rotated and folded when pressure is applied, thereby defining a precise folding zone.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If folding pressure is applied to tabs to enable correct folding, then tabs can be folded towards the central axis, but the folding pressure is transmitted to adjacent portions of the electrode sheet causing unintended folding

Engineering Contradiction:
Improvefolding of tabsVSAvoidfolding zone accuracy
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The electrode sheet is provided with a longitudinal track that locally reduces the thickness only in specific sections where tabs are located. This creates a difference in mechanical properties between the track section (thinner, more flexible) and the rest of the electrode sheet (full thickness, more rigid), allowing folding pressure to be localized to the tabs without transmitting to adjacent portions.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The electrode sheet is segmented into different thickness zones along the longitudinal track. The track creates discrete weakening sections that correspond to tab positions, effectively dividing the electrode sheet into independent folding zones that can be folded without affecting adjacent areas.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If tabs are folded without a predefined folding line, then the process is simpler, but it is not always possible to guarantee folding at the desired folding zone

Engineering Contradiction:
Improvefolding process simplicityVSAvoidfolding zone consistency
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The longitudinal track is created in advance during electrode sheet formation, pre-defining the folding zones before the winding and folding operations. This preliminary structural modification ensures that when folding pressure is later applied, the tabs will naturally fold along the predetermined track path, guaranteeing consistent folding zone location without requiring complex real-time control.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If the electrode sheet is structurally weakened along a longitudinal path, then tabs are more easily rotated and folded about that path, but the structural integrity of the electrode sheet is reduced

Engineering Contradiction:
Improvetab rotation and foldingVSAvoidelectrode sheet structural integrity
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The thickness reduction is applied locally only along the longitudinal track where tabs are positioned, rather than uniformly across the entire electrode sheet. This localized modification provides the necessary flexibility for tab folding while preserving the full structural integrity and mechanical strength of the remaining electrode sheet areas that require strength for electrochemical performance.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4421891A1Method for forming an electrode for electrochemical cells and electrode for electrochemical cells
Publication Date: 2024.08.28 GD SPA
  • EP4421891A1 patent drawingFigure 1
  • EP4421891A1 patent drawingFigure 2~4
  • EP4421891A1 patent drawingFigure 5

AI summary

A method for forming an electrode for electrochemical cells comprises arranging an electrode sheet (11) having a thickness, a length (L) and a height (H), wherein the length (L) is measured along a longitudinal direction, the height (H) is measured along a transverse direction and the thickness is measured along a direction perpendicular to the longitudinal direction and the transverse direction, said electrode sheet (11) having a longitudinal free edge (12a); cutting a plurality of tabs (17) on the electrode sheet (11) in a first portion (15) of the electrode sheet extending transversely from the free edge (12a); reducing the thickness of the electrode sheet (11) along a longitudinal track (20) contained in the first portion (15) of the electrode sheet (11).