Solar Cell Paste Composition with Gallium Compound
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Solution Overview
Problem
Existing solar cell manufacturing processes face challenges in achieving stable and efficient electrode formation with excellent electrical characteristics while maintaining a simple and stable process, as the composition of inorganic materials in the paste composition can affect the efficiency and stability of solar cells.
Innovation Solution
A paste composition for solar cell electrodes is developed, incorporating a glass composition with a gallium compound and lead compound as main network formers, along with additional metal compounds like silicon oxide and zinc oxide, which improves adhesion and reduces resistance by stabilizing the glass formation without increasing firing temperatures, thereby enhancing the efficiency and stability of solar cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a paste composition with inorganic composition is used to form electrodes, then electrical characteristics and adhesion are improved, but the manufacturing process complexity and firing temperature control become more challenging
Solution Approach 1:
The patent modifies the chemical composition parameters of the inorganic materials in the paste composition, specifically incorporating metal compounds like gallium oxide and bismuth oxide alongside lead oxide. This compositional parameter change enables improved electrical characteristics and adhesion while maintaining processability at controlled firing temperatures, thus resolving the contradiction between reliability improvement and manufacturing complexity.
Solution Approach 2:
The patent employs a composite inorganic composition consisting of multiple metal compounds (lead oxide, gallium oxide, bismuth oxide, silicon oxide, zinc oxide) rather than a single material. This composite approach synergistically combines the advantages of each component: lead oxide for adhesion, gallium oxide for low-temperature glass formation, and bismuth oxide for etching enhancement, achieving excellent electrical characteristics without excessive process complexity.
2Reliability
If the inorganic composition is optimized for adhesion and low resistance, then electrode stability is improved, but the risk of over-firing reactions increases
Solution Approach 1:
The patent carefully controls the weight ratios of metal compounds in the inorganic composition, specifying that lead oxide comprises 50-90 wt%, gallium oxide 5-30 wt%, and bismuth oxide 1-10 wt%. These precise parameter specifications ensure optimal adhesion and stability while preventing over-firing reactions by limiting the amounts of reactive components and balancing the overall composition for controlled glass formation at appropriate temperatures.
Solution Approach 2:
The patent introduces gallium oxide and bismuth oxide as intermediary substances that mediate between the lead oxide-based inorganic composition and the passivation layer. These intermediaries facilitate controlled etching and glass formation, improving adhesion and stability while acting as buffers that prevent excessive reactivity and over-firing reactions, thus resolving the contradiction between electrode stability and harmful over-firing effects.
3Reliability
If lead compound is used as main network former, then adhesion is improved, but environmental pollution increases
Solution Approach 1:
The patent creates a composite inorganic composition where lead oxide serves as the primary adhesion-promoting component (50-90 wt%), but its harmful environmental effects are mitigated by incorporating gallium oxide (5-30 wt%) and bismuth oxide (1-10 wt%). These additional compounds contribute to glass formation and etching while reducing the overall environmental impact. The composite structure maintains the essential adhesion function of lead oxide while distributing and reducing the harmful effects through dilution and functional substitution by less toxic materials.
Solution Approach 2:
The patent employs a strategy of using a limited amount of lead oxide (50-90 wt% but not 100%) in the inorganic composition, treating it as a functional component rather than the sole basis of the material system. By incorporating smaller amounts of alternative metal compounds that are more environmentally friendly, the patent reduces the total lead content and its associated pollution while maintaining the necessary adhesion performance. This approach effectively substitutes part of the harmful lead-based material with shorter-lived, less toxic alternatives.
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 paste composition effectively lowers the resistance of solar cell electrodes and improves their stability and uniform efficiency characteristics by promoting adhesion with the conductivity type region, while reducing environmental pollution from lead compounds and preventing over-firing reactions.
Implementation Method 1
an inorganic composition (a glass composition, a glass frit, etc.) including a plurality of metal compounds including a gallium compound including gallium
Implementation Method 2
the paste composition etches the passivation layer by the heat treatment to be connected to the conductivity type region. At this time, an inorganic composition included in the paste composition serves to etch the passivation layer during the heat treatment
Implementation Method 3
improves adhesion and reduces resistance by stabilizing the glass formation without increasing firing temperatures, thereby enhancing the efficiency and stability of solar cells
Data Source
AI summary
Discussed is a paste composition for an electrode of a solar cell, the paste including a conductive powder, an organic vehicle, and an inorganic composition formed by including a plurality of metal compounds including a gallium compound including gallium as a component of a main network former of the inorganic composition.