Conductive Paste Composition for High Aspect Ratio Solar Cell Electrodes
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Solution Overview
Problem
Existing conductive paste compositions for solar cells face challenges in achieving high electrical conductivity while minimizing shadowing and ohmic heating, requiring a balance between small electrode size and high conductivity, which is difficult to achieve with traditional methods.
Innovation Solution
A conductive paste composition comprising a source of electrically conductive metal, glass frit, and an organic vehicle with microgel particles and solvent, applied to a substrate and fired to form fine conductive lines with high aspect ratios, enhancing electrical conductivity and adhesion while minimizing organic vehicle residue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the electrode size is reduced to minimize shadowing, then light absorption efficiency is improved, but electrical conductivity deteriorates
Solution Approach 1:
The electrode is divided into multiple fine conductive lines instead of a single large electrode, allowing the total conductive area to be distributed across the substrate while maintaining individual line thinness to minimize shadowing. This segmentation enables both high light absorption and adequate electrical conductivity through the collective effect of multiple lines.
Solution Approach 2:
The conductive paste uses a composite formulation combining conductive metal particles (silver, aluminum, or copper), glass frit, and organic vehicle with microgel particles. This composite structure provides enhanced electrical conductivity and adhesion properties, enabling fine lines to achieve high conductivity despite reduced cross-sectional area.
2Ease of manufacture
If traditional conductive paste is used, then manufacturing simplicity is maintained, but manufacturing precision deteriorates
Solution Approach 1:
The organic vehicle formulation is modified by incorporating microgel particles with specific size ranges (0.1-10 μm) and controlled swelling properties. These parameter changes in the paste composition enable better rheological control during screen printing, resulting in improved line width precision and reduced spreading while maintaining ease of application.
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 solution enables the formation of high-efficiency solar cells with low series resistance and high fill factor by creating fine conductive structures that maintain high conductivity and stability, effectively addressing the balance between electrode size and conductivity.
Implementation Method 1
firing the conductive paste
Implementation Method 2
the organic vehicle comprising microgel particles and a solvent
Implementation Method 3
firing the substrate and paste composition thereon, whereby the electrically conductive structure is formed on the substrate
Data Source
AI summary
A conductive paste composition comprises (i) an inorganic powder comprising at least a conductive powder, (ii) at least one microgel polymer, and (iii) a solvent. The paste composition may be used in a process for manufacturing an electrical device comprising: preparing a substrate; applying the conductive paste onto the substrate in a preselected pattern; and heating the applied conductive paste to form a conductive structure that provides an electrode for connecting the device. The paste composition beneficially permits the formation of narrow, high aspect ratio features in the conductive structure.