Separator Zigzag Folding Buffer Roller Tension Control

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Solution Overview

Problem

The existing secondary battery manufacturing methods using zigzag stack type devices face challenges in maintaining position accuracy and yield due to variations in separator dimensions, leading to potential fluttering and reduced accuracy of the electrode plate group.

Innovation Solution

The method involves using buffer rollers to maintain a tension-free state during zigzag folding, allowing continuous folding without pre-cutting the separator, and employing ionized air to prevent static electrification, which enables smooth pulling and folding of the separator, thereby improving accuracy and yield.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the separator is suspended in a tension-free state between guide members during zigzag folding, then the position accuracy of the separator and electrode plates is improved, but the separator may flutter and be drawn into the guide members, reducing manufacturing precision

Engineering Contradiction:
Improveposition accuracy of separator and electrode platesVSAvoidseparator stability during folding
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

A buffer roller is introduced as an intermediary element between the separator and the support structure. The buffer roller applies a controlled buffering force to the separator during zigzag folding, preventing it from fluttering and being drawn into guide members while maintaining the tension-free suspension state that ensures position accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The buffering force applied by the buffer roller is dynamically adjusted based on the folding process. By changing the magnitude of the buffering force according to the separator's position and state during zigzag folding, the system maintains both the tension-free condition for accuracy and sufficient stability to prevent fluttering.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If the separator is cut to a specific length before zigzag folding, then the tension-free state and position accuracy are maintained, but the separator yield decreases due to margin parts required for cutting

Engineering Contradiction:
Improveposition accuracy during foldingVSAvoidseparator yield
Core Design Contradiction:
Manufacturing precisionVSLoss of substance

Solution Approach 1:

The separator is supplied continuously without cutting during the zigzag folding process. The buffer roller maintains the tension-free state and position accuracy throughout the continuous folding operation, eliminating the need for margin parts and cutting operations, thereby maximizing separator yield.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The buffer roller is positioned and configured in advance to provide the necessary buffering force before the separator enters the folding zone. This preliminary positioning ensures that the separator maintains its tension-free state throughout the entire folding process without requiring post-cutting adjustments or margin parts.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If multiple guide members are used to fold the separator zigzag, then the folding accuracy is improved, but the device complexity and number of components increase

Engineering Contradiction:
Improvefolding accuracyVSAvoidnumber of guide members
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The buffering function is extracted from the guide members and assigned to a dedicated buffer roller. This separation of functions allows the guide members to focus solely on guiding and folding the separator with high accuracy, while the buffer roller handles the stabilization and flutter prevention, thereby reducing the functional burden and potential complexity of the guide member system.

Inventive Principle:
Principle #2Taking out (Extraction)

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 ensures accurate and efficient zigzag folding of separators with varying dimensions, maintaining product quality and increasing separator yield by preventing fluttering and static attraction, while simplifying the apparatus and reducing the number of guide members required.

Implementation Method 1

a buffer roller which makes contact with one surface of the separator, and is movable vertically; the buffer roller being located at a predetermined upward position or downward position while contacting the separator, during zigzag folding by movement of the guide members, the buffer roller moves downward or upward

Methodology Applied
Scientific EffectBuffering force:

Implementation Method 2

employing ionized air to prevent static electrification

Methodology Applied
Scientific EffectIonized air: Ionisation

Data Source

PatentEP2911229B1Secondary-battery production method and production device
Publication Date: 2019.04.10 ELIIY POWER
  • EP2911229B1 patent drawingFigure 1
  • EP2911229B1 patent drawingFigure 2
  • EP2911229B1 patent drawingFigure 3(a)~3(b)

AI summary

The purpose of the present invention is to enable smooth pulling of a separator by guide members by inhibiting a phenomenon in which, when the separator is being pulled by the guide members, the separator moves in the width direction and rattles. The present invention is provided with: a step in which a separator (4) is zigzaggedly folded by being pulled by guide members (21); and a step in which, while buffer rollers (45, 46), which are disposed between support rollers (42, 43, 44) for supporting the separator (4) at midpoints located at an upstream side of a suspension roller (41) in the conveyance direction, said buffer rollers being formed so as to be capable of coming into contact with an upper surface of the separator (4) and ascending or descending to adjust the positions thereof in the vertical direction, are in a state of being stationed in a prescribed downward position, the separator (4) is suspended from the suspension roller (41) and between the guide members (21), and when the separator is being zigzaggedly folded in accordance with the movement of the guide members (21), the buffer rollers (45, 46) ascend to feed an amount of length of the separator (4), said amount being proportional to that drawin by the guide members (21).