Electro-Conductive Paste Salt Additives for Solar Cell Contact Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current solar cell technologies face challenges in achieving improved performance, specifically increased efficiency and reduced contact resistance between electrodes and wafers, while maintaining cost-effectiveness and environmental sustainability.
Innovation Solution
The use of an electro-conductive paste comprising metallic particles, glass frit, an organic vehicle, and a salt with an anion containing oxygen and halogen atoms (such as Cl, Br, or I) is introduced, which is applied to solar cells and fired at temperatures below 900°C to form electrodes with optimized conductivity and reduced contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electro-conductive paste is used, then the solar cell can be manufactured with standard process, but the contact resistance between electrodes and wafers is high
Solution Approach 1:
The patent introduces a novel salt component (ammonium halide or alkali metal halide) into the electro-conductive paste formulation, changing the chemical composition parameters to achieve lower contact resistance. This parameter change enables the paste to form more conductive interfaces with the silicon wafer during the firing process, directly addressing the high contact resistance issue while maintaining compatibility with standard manufacturing processes.
Solution Approach 2:
The patent creates a composite electro-conductive paste material by combining metallic particles, glass frit, organic vehicle, and the novel salt component. This composite formulation synergistically improves electrical conductivity and contact properties. The salt component acts as a flux that facilitates better bonding and lower contact resistance between the metallic particles and the silicon substrate, while the glass frit provides adhesion and mechanical stability.
2Reliability
If firing temperature is increased to improve electrode formation, then electrode conductivity improves, but energy consumption and material degradation increase
Solution Approach 1:
The addition of salt components (ammonium halide or alkali metal halide) changes the thermal and chemical parameters of the paste formulation. These salts act as fluxes that lower the melting point and enhance the reactivity of the paste during firing, enabling effective electrode formation at reduced temperatures. This parameter change in composition allows achieving good electrode conductivity with lower energy input, thus resolving the contradiction between conductivity improvement and energy consumption.
Solution Approach 2:
The patent replaces the reliance on high thermal energy input with a chemically-active paste formulation that uses the salt component to facilitate lower-temperature sintering and bonding. The chemical activity of the salt substitutes for the mechanical/thermal force that would otherwise be needed to achieve the same electrode quality, thereby reducing energy consumption while maintaining electrode conductivity.
3Productivity
If solar cell efficiency is increased through material optimization, then energy conversion improves, but manufacturing cost increases
Solution Approach 1:
The patent modifies the paste composition by incorporating readily available and inexpensive salt components (ammonium halide or alkali metal halide) that significantly enhance the performance of the electro-conductive paste. This parameter change in formulation achieves improved energy conversion efficiency through better electrical contact without requiring expensive rare materials or complex processing equipment, thus improving productivity while keeping manufacturing costs low.
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
This approach enhances solar cell efficiency and fill factor while minimizing contact resistance, leading to improved energy conversion and durability of solar cells, thus addressing the limitations of existing technologies.
Implementation Method 1
a typical electro-conductive paste contains metallic particles, glass frit, and an organic vehicle... which is fired to give solid electrode bodies
Implementation Method 2
electro-conductive pastes comprising salt additives with an anion comprising an oxygen atom and a halogen atom... enhanced efficiency... reduced contact resistance
Implementation Method 3
Solar cells are devices that convert the energy of light into electricity using the photovoltaic effect
Data Source
Figure 1~2
Figure 3a~3b
Figure 3c~4
AI summary
In general, the present invention relates to electro-conductive pastes with salt additives with anions consisting of halogen and oxygen, and solar cells with high Ohmic sheet resistance, preferably photovoltaic solar cells. More specifically, the present invention relates to electro-conductive pastes, solar cell precursors, processes for preparation of solar cells, solar cells and solar modules. The present invention relates to an electro-conductive paste at least comprising as paste constituents: a) metallic particles; b) a glass frit; c) an organic vehicle; and d) a salt with an anion comprising an oxygen atom and a halogen atom.