Separator Adhesive Coating for Precise Electrode Alignment

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Solution Overview

Problem

Existing electrode assembly manufacturing methods result in skew failure due to positional deviation of electrodes between separators, leading to inefficiencies and potential performance degradation in secondary batteries.

Innovation Solution

An adhesive layer coating unit applies a uniform adhesive layer with controlled width and thickness on a separator using a transfer roller, discharge roller, and curing member, ensuring precise alignment and bonding of electrodes and separators.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electrodes and separators are alternately stacked during electrode assembly manufacturing, then the electrode assembly structure is formed, but the electrode position shakes and deviates causing skew fail

Engineering Contradiction:
Improveelectrode position stabilityVSAvoidelectrode alignment precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The adhesive layer is applied to the separator surface before the electrode is disposed on it. This preliminary action of coating the adhesive layer ensures that when the electrode is placed on the separator, it is immediately bonded in the correct position, preventing positional deviation and skew fail during the stacking process

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

An adhesive layer is introduced as an intermediary substance between the separator and the electrode. This adhesive layer acts as a bonding medium that secures the electrode to the separator, preventing the electrode from shaking and deviating during assembly and operation

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If adhesive is applied to bond electrode and separator, then bonding strength is improved, but adhesive layer uniformity in width and thickness is difficult to control

Engineering Contradiction:
Improvebonding strengthVSAvoidadhesive layer uniformity
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The coating head height relative to the separator surface is precisely controlled and optimized. By adjusting this parameter (the vertical distance between the coating head and separator), the adhesive is delivered with optimal force and distribution, resulting in a uniform adhesive layer with consistent width and thickness while maintaining strong bonding

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The coating groove on the discharge roller creates a standardized template or pattern for adhesive distribution. The groove's dimensions (width and depth) are precisely controlled, and this geometry is copied onto the separator surface with each rotation, ensuring uniform adhesive layer dimensions across the entire bonding area

Inventive Principle:
Principle #26Copying

3Manufacturing precision

If adhesive layer is applied before electrode disposal, then electrode positioning accuracy is improved, but additional coating process step is added

Engineering Contradiction:
Improveelectrode positioning accuracyVSAvoidcoating process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The adhesive coating function is merged with the existing separator transfer process. The discharge roller that already exists for transferring separators is modified to include a coating groove, and the coating head is integrated into this existing pathway. This combination allows adhesive application without requiring a completely separate coating system, thus improving positioning accuracy while minimizing added complexity

Inventive Principle:
Principle #5Merging (Combining)

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

Prevents skew failure of electrodes during assembly, enhances manufacturing efficiency, and maintains battery performance by ensuring consistent adhesive application and bonding.

Implementation Method 1

a coating groove (122a) having the first width and a closed curve shape is formed in a circumferential surface of the discharge roller (122)... as the adhesive (12a) flows in the coating groove (122a) of the discharge roller (122), the adhesive layer (12) having the first width is continuously applied on the top surface of the first separator (11)

Methodology Applied
Scientific EffectAdhesive transfer through contact: Adhesive

Implementation Method 2

a curing member (130) which emits a light source toward the first separator (11) and cures the adhesive layer (12), which is continuously applied on the first separator (11), to a set viscosity

Methodology Applied
Scientific EffectLight-induced curing: Photopolymerisation

Data Source

PatentEP4131532B1Adhesive layer coating unit, electrode assembly manufacturing apparatus and electrode assembly manufacturing method
Publication Date: 2025.07.16 LG ENERGY SOLUTION LTD
  • EP4131532B1 patent drawingFigure 1
  • EP4131532B1 patent drawingFigure 2
  • EP4131532B1 patent drawingFigure 3

AI summary

The present invention provides an adhesive layer coating unit configured to continuously apply an adhesive layer having a first width in a longitudinal direction of a first separator. The adhesive layer coating unit comprises: a transfer roller configured to support a bottom surface of the first separator and transfer the first separator; a discharge roller configured to transfer the first separator, which has passed through the transfer roller, in conjunction with the transfer roller while supporting a top surface of the first separator, wherein a coating groove having the first width and a closed curve shape is formed in a circumferential surface of the discharge roller; and a coating member configured to inject an adhesive into a space between the discharge roller and the top surface of the first separator which has passed through the transfer roller. As the adhesive flows in the coating groove of the discharge roller, the adhesive layer having the first width is continuously applied on the top surface of the first separator.