Jelly Roll Coiling Device With Feedback Tension Control

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Solution Overview

Problem

The challenge in battery assembly is achieving consistent and controlled tension during the coiling of jelly roll electrode assemblies, which is crucial for compactness and efficiency, while avoiding damage to the jelly roll and ensuring proper circuit completion without wasting space or reducing battery capacity.

Innovation Solution

An automated coiling device with a winding apparatus, upper and lower spools, and a platform that supports a mandrel, allowing for controlled tension through a feedback loop and secure attachment of electrodes and separator strips, ensuring consistent coiling and secure attachment of electrodes to the mandrel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the jelly roll is wrapped tightly to eliminate dead space and increase battery capacity, then the battery footprint is maximized for power storage, but the mandrel removal process may pull the core of the jelly roll out and damage the assembly

Engineering Contradiction:
Improvebattery capacityVSAvoidjelly roll integrity
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

A removable connector is introduced as an intermediary component between the mandrel and the electrode assembly. This connector allows the mandrel to be securely held during the coiling process to maintain tight winding, then easily removed afterward without damaging the jelly roll core, thus resolving the contradiction between tight wrapping and damage prevention

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The electrode assembly is coiled around the mandrel with the connector in place before the final assembly steps. This preliminary coiling with support ensures tight winding without risk of core displacement, and the connector is removed only after coiling is complete, preventing damage during the critical winding phase

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the jelly roll is wrapped loosely to avoid mandrel removal damage, then the jelly roll integrity is maintained, but space is wasted and battery capacity decreases

Engineering Contradiction:
Improvejelly roll integrityVSAvoidbattery capacity
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The removable connector serves as a protective intermediary during the coiling process, enabling tight winding without the risk of core displacement. This allows the jelly roll to be wrapped tightly to maximize capacity while the connector prevents the damage that would otherwise occur during mandrel removal

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If automated coiling is implemented to improve manufacturing efficiency, then productivity increases, but controlling consistent tension during coiling becomes more complex

Engineering Contradiction:
Improvecoiling efficiencyVSAvoidtension control system
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The automated coiling device incorporates a feedback control system with a brake mechanism that responds to tension variations during coiling. This feedback loop maintains consistent tension on the electrode assembly throughout the winding process, enabling high-speed automated production while preventing over-tensioning or loose winding that would compromise quality

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2625739B1Coiling device for making an electrode assembly and methods of use
Publication Date: 2017.05.31 MEDTRONIC INC
  • EP2625739B1 patent drawingFigure 1
  • EP2625739B1 patent drawingFigure 2
  • EP2625739B1 patent drawingFigure 3A~3B

AI summary

A system for the automated coiling of a jelly roll electrode assembly for controlled assembly and tensioning of jelly roll assembly is provided. The system includes: a shuttle (100), and a mandrel (130) to which electrodes (160,162) are welded; a base (60), mateable with the shuttle and on which the battery head assembly is mounted for welding to the mandrel; and a coiling device (10). The coiling device has an upper spool (32), a lower spool (34), holding a separator strip (36) and a platform between the two holding the base. The separator strip is threaded through a passage (P) in the mandrel separating positive and negative portions (132,134). Rotating the mandrel coils the positive electrode, the separator strip and the negative electrode to coil around the mandrel. The coiling device may include a feedback loop braking one or both spools and allowing the coiling tension to be programmed to a desired level.