Patterned Adhesive Separator for Secondary Battery Wettability

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Solution Overview

Problem

Conventional secondary battery manufacturing processes result in low wettability at the electrode-separator interface due to uniform adhesive forces, leading to degraded battery performance and difficulties in gas discharge during the formation process.

Innovation Solution

A unit cell design with patterned adhesive forces between the electrode and separator, achieved by plasma treatment of specific regions, allowing for improved electrolyte impregnation and gas discharge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If uniform adhesive force is applied between electrode and separator, then complete uniform adhesion is achieved, but electrolyte wettability is reduced

Engineering Contradiction:
Improveadhesive forceVSAvoidelectrolyte wettability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The separator is designed with regions of different adhesive forces: a first region with strong adhesive force (plasma-treated) for secure bonding, and a second region with weak adhesive force (non-plasma-treated) for improved electrolyte wettability. This local differentiation resolves the contradiction by providing both strong adhesion where needed and good wettability where required.

Inventive Principle:
Principle #3Local quality

2Strength

If strong adhesive force is applied at positive electrode-separator interface, then bonding strength is improved, but electrolyte penetration is hindered

Engineering Contradiction:
Improvebonding strength at positive electrode interfaceVSAvoidelectrolyte penetration
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The separator has a first region specifically configured to contact the positive electrode with strong adhesive force through plasma treatment, while a second region provides weak adhesive force to facilitate electrolyte penetration. This local quality differentiation allows the positive electrode interface to have both strong bonding and adequate electrolyte access.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The separator surface is segmented into multiple regions with different adhesive properties. The first region (plasma-treated) provides strong adhesion for the positive electrode, while the second region (non-plasma-treated) allows electrolyte penetration, thus resolving the contradiction through spatial segmentation of functional zones.

Inventive Principle:
Principle #1Segmentation

3Strength

If uniform high adhesive force is applied, then electrode-separator bonding is strengthened, but gas discharge is impeded

Engineering Contradiction:
Improveelectrode-separator bondingVSAvoidgas discharge
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The separator incorporates a second region with weak adhesive force that serves as a gas discharge pathway. This local quality differentiation allows the majority of the interface to maintain strong bonding while providing dedicated zones for gas venting, thus resolving the contradiction between bonding strength and gas discharge capability.

Inventive Principle:
Principle #3Local quality

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

Enhances electrolyte wettability and facilitates smooth gas removal during battery formation, thereby improving secondary battery performance.

Implementation Method 1

The separator has a patterned adhesive force. The first region is a region treated with plasma, and the second region is a region not treated with plasma.

Methodology Applied
Scientific EffectPlasma treatment: Plasma

Data Source

PatentEP3396767B1Unit cell for secondary battery with improved wettability and method for manufacturing the same
Publication Date: 2022.09.14 LG ENERGY SOLUTION LTD
  • EP3396767B1 patent drawingFigure 1~4
  • EP3396767B1 patent drawingFigure 5~6
  • EP3396767B1 patent drawingFigure 7~9

AI summary

A unit cell for a secondary battery includes a central electrode having a first polarity, a pair of separators respectively laminated on both surfaces the central electrode, and an upper electrode and a lower electrode respectively laminated on the pair of separators and having a second polarity, wherein the separator has a patterned adhesive force.