LiAlO2 Conductive Paste for Solar Cell Adhesion

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Solution Overview

Problem

Conventional conductive pastes for forming electrodes in solar cells exhibit insufficient adhesion strength to semiconductor substrates, leading to inferior solar cell performance in terms of photovoltaic conversion efficiency and fill factor.

Innovation Solution

Incorporation of LiAlO2 into the conductive paste composition, which includes a conductive metal, glass frit, and an organic medium, enhances the adhesion strength of the electrodes to the substrate, improving the electrical connection and performance of solar cells.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional conductive paste composition is used, then the electrode can be formed on semiconductor substrate, but the adhesion strength between electrode and substrate is insufficient

Engineering Contradiction:
Improveadhesion strengthVSAvoidelectrode-substrate bonding reliability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent applies composite materials by incorporating LiAlO2 particles into the conductive paste formulation. This creates a multi-component system where LiAlO2 serves as an adhesion promoter that forms strong chemical bonds with both the aluminum electrode and the silicon substrate, while the conductive metal particles maintain electrical conductivity. The composite paste composition achieves superior adhesion strength and bonding reliability compared to conventional single-component pastes.

Inventive Principle:
Principle #40Composite materials

2Strength

If LiAlO2 is incorporated into conductive paste, then adhesion strength is enhanced, but the complexity of paste composition increases

Engineering Contradiction:
Improveadhesion strengthVSAvoidpaste composition complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by optimizing the concentration of LiAlO2 in the conductive paste to a specific range (0.1-5 wt%). This parameter optimization ensures that sufficient adhesion promoter is present to enhance bonding strength, while excessive amounts that would unnecessarily increase composition complexity are avoided. The controlled parameter range achieves the desired adhesion enhancement with minimal impact on paste formulation complexity.

Inventive Principle:
Principle #35Parameter changes

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 addition of LiAlO2 significantly increases the adhesion strength of the electrodes to various semiconductor substrates, resulting in solar cells with comparable or better photovoltaic conversion efficiency and fill factor compared to LiAlO2-free conductive pastes.

Implementation Method 1

incorporation of LiAlO2 (lithium aluminate) therein... provides enhanced adhesion strength of an electrode prepared therefrom to a substrate

Methodology Applied
Scientific EffectChemical bonding: Chemical Bonding

Implementation Method 2

the front side silver paste sinters and penetrates through an anti-reflective layer (e.g., SiNx film) during firing and thereby achieves electrical contact with a semiconductor substrate

Methodology Applied
Scientific EffectSintering: Sintering

Data Source

PatentUS10431700B2Conductive paste composition for providing enhanced adhesion strength to a semiconductor substrate and its use
Publication Date: 2019.10.01 GIGA SOLAR MATERIALS CORPORATION

AI summary

The present invention relates to a conductive paste, which imparts an electrode formed therefrom with enhanced adhesion strength to a semiconductor substrate by incorporation of LiAlO2 (lithium aluminate) therein. The present invention further relates to an electrode formed from the conductive paste and a semiconductor and in particular, a solar cell comprising the electrode produced therefrom.