Solar Cell Electrode Paste with Burn-out Retardant
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Solution Overview
Problem
Solar cell electrodes face challenges in minimizing contact resistance and maintaining efficiency as the area of the solar cell increases, requiring a composition that balances conductive powder, glass frit, and organic vehicle to reduce series resistance and firing temperature variability while ensuring thermal stability and adhesion.
Innovation Solution
A composition for forming electrodes that includes a conductive powder, glass frit, and a burn-out retardant with residual carbon, which adjusts fluidity and etching properties to minimize contact resistance and enhance open circuit voltage, comprising 60-95% conductive powder, 0.5-20% glass frit, and 0.05-1.5% burn-out retardant, along with an organic vehicle and optional additives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the area of the solar cell is increased, then the power output is improved, but the contact resistance increases and series resistance worsens
Solution Approach 1:
The patent modifies the chemical composition parameters of the electrode paste by introducing a burn-out retardant compound and adjusting the ratios of conductive powder, glass frit, and organic vehicle. This changes the thermal and electrical properties of the paste, enabling lower contact resistance even in large-area solar cells where traditional formulations would fail.
Solution Approach 2:
The patent creates a composite electrode paste formulation combining multiple components with specific functions: conductive powder for electrical conductivity, glass frit for adhesion and wetting, organic vehicle for printability, and burn-out retardant for controlled decomposition. This composite approach allows optimization of multiple properties simultaneously to address the scaling challenge.
2Manufacturing precision
If the firing temperature is increased, then the electrode formation is improved, but the thermal stability and energy consumption worsen
Solution Approach 1:
The patent changes the decomposition temperature parameters of the organic vehicle by selecting specific burn-out retardant compounds that decompose at lower temperatures. This allows the electrode formation process to occur at reduced firing temperatures, lowering energy consumption while maintaining adequate electrode quality through the synergistic composition of paste components.
3Reliability
If the conductive powder content is increased, then the electrical conductivity is improved, but the adhesion and fluidity worsen
Solution Approach 1:
The patent optimizes the concentration parameters of all paste components, particularly adjusting the ratio of conductive powder to glass frit and organic vehicle. The burn-out retardant compound further modifies the rheological parameters during firing, enabling high conductive powder content to be maintained while preserving adhesion through controlled sintering behavior and glass frit wetting action.
4Strength
If the glass frit content is increased, then the adhesion is improved, but the firing temperature and series resistance worsen
Solution Approach 1:
The patent modifies the chemical composition parameters of the glass frit and optimizes its content ratio to achieve a balance where sufficient adhesion is obtained without excessive firing temperature requirements. The burn-out retardant compound contributes to lowering the effective firing temperature, allowing adequate glass frit content for adhesion while minimizing its negative impact on series resistance through reduced thermal processing.
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 effectively reduces series resistance, maintains electrical characteristics, and increases open circuit voltage, thereby improving solar cell efficiency and thermal stability across varying firing temperatures.
Implementation Method 1
The burn-out retardant may have residual carbon, in terms of an amount, of greater than or equal to about 1 wt %, based on an initial amount of 100 wt %, at a temperature of about 600° C.
Implementation Method 2
The burn-out retardant may exhibit an exothermic peak at about 200° C. to about 500° C.
Implementation Method 3
a conductive powder... effectively reduces series resistance
Implementation Method 4
glass frit... adjusts fluidity and etching properties
Data Source
AI summary
A composition for forming an electrode includes a conductive powder, a glass frit, an organic vehicle, and a burn-out retardant. The burn-out retardant exhibits a residual carbon of greater than or equal to about 1 wt % at a temperature of about 600° C. based on the initial amount of 100 wt % and an exothermic peak at about 200° C. to about 500° C.