Flexible Electrode Hierarchical Pattern Manufacturing

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Solution Overview

Problem

Conventional methods for creating flexible batteries face challenges in maximizing energy density and structural extensibility due to bonding issues between flexible substrates and active material layers, which are compromised by elongation and contraction, and the use of extensible connectors reduces energy density.

Innovation Solution

A manufacturing method involving a polymer substrate with pre-patterned first and second uneven patterns, where a tensile force is applied to form the patterns, and a carbon nanotube network thin film is used to enhance bonding strength and surface area, allowing for improved energy density and flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the thickness of the active material layer is reduced to secure flexibility, then flexibility is improved, but the energy density decreases

Engineering Contradiction:

ImproveflexibilityVSAvoidenergy density

Core Design Contradiction:

Ease of operationVSQuantity of substance

Solution Approach 1:

The invention transitions from a flat two-dimensional substrate to a three-dimensional hierarchical uneven pattern structure. By forming first uneven patterns on the substrate surface and then forming second uneven patterns on the protruding portions, the structure gains vertical dimensionality, dramatically increasing the surface area available for active material deposition without increasing the overall device thickness, thus maintaining flexibility while improving energy density.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The invention implements a nested hierarchical structure where second uneven patterns are formed on the protruding portions of the first uneven patterns. This nested arrangement creates multiple levels of surface complexity, maximizing the surface area within a confined vertical space, allowing the active material layer to have greater contact area with the substrate without increasing the overall thickness of the flexible battery structure.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Area of stationary object

If a tensile force is applied to form uneven patterns on the substrate, then the surface area is maximized, but the active material layer may be damaged

Engineering Contradiction:

Improvesurface areaVSAvoidintegrity of active material layer

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The invention applies preliminary actions by first forming the first uneven patterns on the substrate before depositing the active material layer. Then, while maintaining the tensile force, the active material is deposited onto the pre-formed uneven patterns. This preliminary structuring allows the material to conform to the patterned surface under controlled tension, and subsequent removal of the tensile force creates the final hierarchical structure without subjecting the deposited material to damaging mechanical stress.

Inventive Principle:

Principle #10Preliminary action

3Ease of operation

If conventional coating methods are used on flexible substrates, then flexibility is maintained, but bonding problems occur between substrate and active material layer during contraction or elongation

Engineering Contradiction:

ImproveflexibilityVSAvoidbonding strength

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The invention replaces flat planar surfaces with curved three-dimensional uneven patterns. The protruding portions and recessed portions create a curved hierarchical topography that allows the structure to accommodate mechanical deformation more effectively. When the flexible substrate contracts or elongates, the curved surfaces can deform elastically without creating stress concentration points, maintaining strong bonding between the substrate and active material layer while preserving flexibility.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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

The method achieves enhanced energy density and structural extensibility by forming a hierarchical uneven pattern structure without damaging the active material, improving bonding strength and flexibility, suitable for wearable devices.

Implementation Method 1

forming a polymer substrate configured to have a first uneven pattern on a first surface thereof

Methodology Applied

Scientific EffectMechanical deformation: Deformation

Implementation Method 2

coating a carbon nanotube (CNT) network thin film on the first uneven pattern

Methodology Applied

Scientific EffectAdhesion: Adhesive

Implementation Method 3

forming a second uneven pattern on the polymer substrate and the electrode active material layer by removing the tensile force

Methodology Applied

Scientific EffectSurface area expansion through pattern formation:

Data Source

PatentUS10026965B2Method for manufacturing electrode structure for flexible energy storage device, electrode structure manufactured thereby, and energy storage device including same

Publication Date: 2018.07.17 KOREA INST OF MACHINERY & MATERIALS

AI summary

An exemplary embodiment of the present invention provides a manufacturing method of an electrode structure for an energy storage device, the method including: forming a polymer substrate configured to have a first uneven pattern on a first surface; forming an electrode active material layer on the first uneven pattern in a state that an tensile force is applied to the polymer substrate; and forming a second uneven pattern on the polymer substrate and the electrode active material layer by removing the tensile force.