Solar Cell Electrode Composition Shrinkage Control
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Solution Overview
Problem
Existing solar cell electrode compositions face challenges in reducing post-baking shrinkage while maintaining excellent processability and electrical properties, such as contact resistance and open circuit voltage.
Innovation Solution
A composition for solar cell electrodes comprising a conductive powder, a bismuth-tellurium-oxide-based glass frit, and either a cyclosiloxane or silsesquioxane compound, with specific weight percentages and additives, which helps in reducing area change rate and improving electrical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrode compositions are used, then the composition can be easily processed and applied, but the area change rate after baking is high leading to poor reliability
Solution Approach 1:
The patent modifies the chemical composition parameters of the electrode material by incorporating specific cyclosiloxane compounds (D4, D5, D6) and silsesquioxane compounds in controlled amounts (0.1-2 wt%). This compositional parameter change reduces the area change rate after baking while preserving good printability and electrical properties, resolving the contradiction between reliability and ease of manufacture.
Solution Approach 2:
The patent creates a composite electrode composition by combining conductive powder, glass frit, organic vehicle, and specific amounts of cyclosiloxane/silsesquoxane compounds. This composite material approach achieves both low area change rate (high reliability) and good processability by synergistically combining multiple material components with complementary properties.
2Reliability
If the composition is optimized for low area change rate, then reliability improves, but electrical properties such as contact resistance may deteriorate
Solution Approach 1:
The patent carefully controls the concentration parameters of cyclosiloxane/silsesquoxane compounds within the optimal range of 0.1-2 wt%. This precise parameter control ensures that the area change rate is reduced while maintaining adequate electrical properties such as contact resistance and open circuit voltage, resolving the contradiction between reliability and manufacturing precision.
Solution Approach 2:
The patent applies different functional components in specific proportions: conductive powder (60-95 wt%) for electrical conductivity, glass frit (0.1-20 wt%) for adhesion and low melting, organic vehicle (1-30 wt%) for processability, and cyclosiloxane/silsesquoxane (0.1-2 wt%) for shrinkage control. This localized quality distribution ensures both low area change rate and good electrical properties are achieved simultaneously.
3Strength
If more glass frit is added to improve adhesion, then bonding strength increases, but the area change rate increases
Solution Approach 1:
The patent optimizes the glass frit content parameter within the range of 0.1-20 wt% and combines it with specific amounts of cyclosiloxane/silsesquoxane compounds (0.1-2 wt%). This coordinated parameter control achieves the balance where glass frit provides adequate adhesion while the cyclosiloxane/silsesquoxane compounds constrain shrinkage to maintain low area change rate, resolving the contradiction between strength and reliability.
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 composition achieves a low area change rate, ensuring excellent processability and reliability, along with improved electrical properties like contact resistance and open circuit voltage, thereby enhancing solar cell efficiency.
Implementation Method 1
the composition may have an area change rate of about 60% or less, as calculated according to the following Equation 1: Area change rate=(|S1−S0/S0)×100 wherein, in Equation 1, S0 denotes a cross-sectional area in μm2 of an electrode formed by printing the composition for solar cell electrodes and not subjected to drying and baking, and S1 denotes a cross-sectional area in μm2 of the electrode subjected to drying at 300° C. for 40 seconds and baking at 800° C. for 60 seconds
Implementation Method 2
a glass frit; at least one of a cyclosiloxane compound and a silsesquoxane compound
Implementation Method 3
a conductive powder
Implementation Method 4
an organic vehicle
Data Source
AI summary
A composition for solar cell electrodes, an electrode formed of the same, and a method of forming an electrode, the composition including a conductive powder; a glass frit; at least one of a cyclosiloxane compound and a silsesquioxane compound; and an organic vehicle.