Solar Cell Electrode Composition with Porous Silver Powder
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Solution Overview
Problem
Silicon-based solar cells face challenges in achieving low series resistance and high conversion efficiency due to limitations in the sintering and adhesion properties of traditional conductive powders used in their electrodes.
Innovation Solution
A composition for solar cell electrodes comprising a conductive powder with a first silver powder having specific cross-sectional particle porosity and average particle diameter, combined with a glass frit and organic vehicle, which promotes sintering and reduces series resistance, thereby improving the formation of a dense conductive film and enhancing conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional conductive powders are used in solar cell electrodes, then the manufacturing process is simple, but the series resistance is high and conversion efficiency is low
Solution Approach 1:
The patent changes the physical and chemical parameters of the conductive powder by controlling the particle porosity (0.1% to 6%) and average particle diameter (0.5 μm to 3.5 μm) of silver powder. This parameter optimization enables better sintering properties and lower series resistance while maintaining manufacturing simplicity through conventional screen printing and firing processes.
Solution Approach 2:
The patent creates a composite conductive paste formulation combining silver powder with specific porosity characteristics, glass frit, and organic vehicle. This composite approach improves adhesion to the substrate and sintering behavior, resulting in lower series resistance and higher conversion efficiency without complicating the manufacturing process.
2Strength
If conductive powder with low porosity is used, then adhesion to substrate improves, but sintering density decreases
Solution Approach 1:
The patent optimizes the porosity parameter within a specific range (0.1% to 6%) to achieve the optimal balance between adhesion and sintering density. This controlled porosity provides sufficient surface area for adhesion while maintaining adequate density for electrical conductivity after sintering.
Solution Approach 2:
The patent creates different local properties within the conductive powder particles by controlling the internal pore structure. The porous interior provides adhesion sites while the outer structure maintains density, achieving both requirements simultaneously through spatial differentiation of material properties.
3Ease of manufacture
If conductive powder with large particle diameter is used, then manufacturing is easier, but series resistance increases
Solution Approach 1:
The patent optimizes the particle diameter parameter within the range of 0.5 μm to 3.5 μm to achieve the optimal balance between manufacturability and electrical performance. This size range ensures adequate flowability for screen printing while providing sufficient surface area for sintering and low series resistance.
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 proposed composition results in reduced series resistance and improved solar cell conversion efficiency by facilitating the formation of a dense conductive film and enhancing the adhesion of the conductive powder to the substrate, as demonstrated by the fabrication of solar cells with improved performance metrics.
Implementation Method 1
the conductive powder includes a first silver powder having a cross-sectional particle porosity of about 0.1% to about 6%
Implementation Method 2
enhancing the adhesion of the conductive powder to the substrate
Data Source
AI summary
A composition for solar cell electrodes, a solar cell electrode, and a method of manufacturing a solar cell, the composition including a conductive powder; a glass frit; and an organic vehicle, wherein the conductive powder includes a first silver powder having a cross-sectional particle porosity of about 0.1% to about 6%.