Conductive Paste Oxide Etching Agent for Solar Cell Adhesion
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Solution Overview
Problem
The existing front-side conductive paste for crystalline silicon solar cells fails to effectively etch anti-reflective insulating layers, resulting in high sheet resistance, decreased adhesion, and increased contact resistance between the electrode and the solar cell surface, which lowers photoelectric conversion efficiency and reliability.
Innovation Solution
A conductive paste formulation with a specific oxide etching agent composition, including PbO, MgO, and Li2O, that dissolves silver during sintering, facilitating the formation of fine silver nanoparticles for improved ohmic contact and adhesion, while effectively etching the anti-reflective layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional front-side conductive paste and oxide etching agent are used, then the manufacturing process is simple, but the etching capability on high sheet resistance surfaces is insufficient, resulting in high contact resistance and poor adhesion
Solution Approach 1:
The patent applies composite materials by formulating a multi-component oxide etching agent system comprising PbO, MgO, and Li2O in specific proportions. This composite etching agent combines the etching capabilities of different oxides to effectively penetrate high sheet resistance anti-reflective layers, achieving both improved adhesion and controlled complexity through a systematic material composition
Solution Approach 2:
The patent applies parameter changes by optimizing the compositional parameters of the oxide etching agent, specifically controlling the weight percentages of PbO (1-5%), MgO (10-40%), and Li2O (30-50%). By adjusting these chemical composition parameters, the etching agent achieves enhanced penetration capability through high resistance layers while maintaining reliable adhesion
2Reliability
If conventional conductive paste is used, then the production cost is low, but the photoelectric conversion efficiency is reduced due to high contact resistance
Solution Approach 1:
The patent applies parameter changes by precisely controlling the quantity parameters of oxide etching agent components within optimal ranges: PbO at 1-5%, MgO at 10-40%, and Li2O at 30-50% by weight. This parameter optimization ensures sufficient etching capability to reduce contact resistance and improve photoelectric conversion efficiency while minimizing the total amount of additives required
Solution Approach 2:
The patent applies the intermediary principle by using the oxide etching agent as a mediator substance that facilitates the interaction between the conductive paste and the high sheet resistance anti-reflective layer. The etching agent acts as an intermediate medium that enables effective penetration and contact formation without requiring excessive quantities of other materials
3Reliability
If existing oxide etching agent is used, then the formulation is simple, but the penetration capability through anti-reflective insulating layer is insufficient
Solution Approach 1:
The patent applies composite materials by creating a multi-element oxide etching agent system with PbO, MgO, and Li2O components in specific mole ratios. This composite formulation synergistically combines the etching properties of different oxides to achieve effective penetration through anti-reflective insulating layers, reducing contact resistance through the coordinated action of multiple substances
Solution Approach 2:
The patent applies parameter changes by optimizing the mole ratio parameters of the oxide components: PbO at 0.1-5%, MgO with specific ratios to PbO (10:5 to 40:0.1) and to Li2O (10:30 to 40:5). These parameter adjustments fine-tune the chemical reactivity and penetration capability of the etching agent, achieving low contact resistance while managing formulation complexity
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 solution reduces contact resistance, enhances electrical conductivity, and improves the adhesion of the front-side electrode, leading to increased conversion efficiency and reliability of the solar cell.
Implementation Method 1
dissolves silver during sintering, facilitating the formation of fine silver nanoparticles
Implementation Method 2
a conductive paste is applied to a silicon cell chip by screen printing, and a front-side electrode is formed on the front side of the silicon cell chip by sintering
Implementation Method 3
an oxide etching agent in the conductive paste etches and penetrates an anti-reflective insulating layer such as silicon nitride, titanium oxide, aluminum oxide, silicon oxide, or silicon oxide/titanium oxide
Data Source
AI summary
A front-side conductive paste for a crystalline silicon solar cell chip is provided. The front-side conductive paste for a crystalline silicon solar cell chip includes, in parts by weight, 80.0-93.0 parts of a metal powder, 6.0-15.0 parts of an organic carrier, and 1.0-5.0 parts of an oxide etching agent. The oxide etching agent contains at least 10-40% of MgO, 0.1-5% of PbO, and 5-30% of Li2O based on 100% by mole, with the molar ratio of MgO:PbO being 10:5˜40:0.1, and the mole ratio of MgO:Li2O being 10:30˜40:5. The metal powder forms good ohmic contact with crystalline silicon substrate during the sintering process of the front-side conductive paste applied overlying an insulation film on the substrate. Finally, a front-side electrode of low contact resistance, good electrical conductivity, and strong adhesion is obtained.