Ink Composition for Solar Battery Pattern Formation

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Solution Overview

Problem

Conventional ink compositions for inkjet printing are highly viscous, making it difficult to form patterns on uneven silicon substrates in solar battery manufacturing processes, which can lead to damage and poor line widths.

Innovation Solution

An ink composition comprising a polymerizable compound with ethylenically unsaturated bonds, a fluorinated surfactant, and a solvent, with adjustable solid content and thermal treatment, is used for non-contact inkjet printing to form patterns on uneven silicon substrates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional highly viscous ink composition is used for inkjet printing, then the ink composition can be applied, but it flows across the uneven silicon substrate making it difficult to form patterns

Engineering Contradiction:

Improvepattern formation precisionVSAvoidink flow across uneven substrate

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent adjusts the viscosity parameter of the ink composition by selecting specific polymerizable compounds (acrylates, methacrylates) with controlled molecular weights and by optimizing the solid content (5-50%) and solvent composition. These parameter changes enable the ink to maintain stability on uneven silicon substrates during inkjet printing while still forming precise patterns after curing.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If screen printing method is used to form patterns, then materials can be applied to substrates, but it is difficult to obtain fine line widths necessary for solar batteries

Engineering Contradiction:

Improveline width precisionVSAvoidprinting method complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical contact-based screen printing method with a non-contact inkjet printing system. This substitution eliminates the physical contact between the screen mesh and substrate, enabling precise deposition of ink in fine line patterns without the limitations of screen mesh opening sizes, while also reducing device complexity by removing the screen assembly.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes the hydraulic properties of the ink composition (viscosity, surface tension, flow characteristics) to enable precise droplet ejection and placement through the inkjet system. By optimizing the ink's rheological properties, the system achieves fine line width control through fluid dynamics rather than mechanical constraints.

Inventive Principle:

Principle #29Pneumatics and hydraulics

3Reliability

If screen printing method is used on thin silicon substrates, then patterns can be formed, but solar cells are easily damaged or broken due to physical contact

Engineering Contradiction:

Improvesubstrate integrityVSAvoidpattern formation ease

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces the mechanical contact process of screen printing with a non-contact inkjet printing method. This eliminates the physical force applied to thin silicon substrates during pattern formation, preventing damage and breakage while maintaining the ability to form required patterns. The ink is deposited through aerosol or liquid droplet ejection without mechanical pressure on the substrate.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Manufacturing precision

If conventional ink composition is used for inkjet printing, then printing can be performed, but fine patterns cannot be formed on uneven silicon substrates

Engineering Contradiction:

Improvefine pattern formationVSAvoidcompatibility with uneven substrate

Core Design Contradiction:

Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The patent optimizes multiple ink composition parameters including viscosity (through polymerizable compound selection), surface tension (through surfactant addition), and solid content (5-50%) to achieve compatibility with uneven silicon substrates. These parameter adjustments allow the ink to properly flow and adhere to uneven surfaces while maintaining fine pattern definition capability.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite ink composition by combining polymerizable compounds (acrylates, methacrylates), solvents, surfactants, and optional additives in specific ratios. This composite formulation provides the dual functionality of adapting to uneven substrate topography while enabling precise fine pattern formation through controlled curing.

Inventive Principle:

Principle #40Composite materials

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 ink composition allows for the formation of fine, uniform patterns on uneven silicon substrates, enhancing the manufacturing process by preventing damage and ensuring high-quality line patterns.

Implementation Method 1

a polymerizable compound having an ethylenically unsaturated bond; thermally treating the applied ink composition

Methodology Applied

Scientific EffectPolymerization: Photopolymerisation

Implementation Method 2

a fluorinated surfactant

Methodology Applied

Scientific EffectSurfactant action: Surfactant

Data Source

PatentUS9302466B2Ink composition usable in solar battery manufacturing process, and method of forming pattern using the same

Publication Date: 2016.04.05 LG CHEM LTD

AI summary

Provided are an ink composition usable in a solar battery manufacturing process, a method of forming a pattern using the ink composition, an insulation film formed of the ink composition, and an etching mask formed of the ink composition. The ink composition includes: a) a polymerizable compound having an ethylenically unsaturated bond; b) a fluorinated surfactant; and c) a solvent, wherein the ink composition has a solid content of 45 parts by weight to 99.99 parts by weight.