Conductive Paste for Solar Cell Electrodes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing conductive pastes for solar cell electrodes lack optimal electrical conductivity and adhesion, leading to subpar performance in silicon solar cells, particularly in forming dense, efficient electrodes with high electrical characteristics.
Innovation Solution
A conductive paste composition comprising 60-95 wt% conductive powder, 0.1-5.0 wt% lead-tellurium-oxide powder, 3-38 wt% organic medium, and 0.1-1.5 wt% inorganic oxide powder, specifically designed to enhance electrical conductivity and adhesion by using high-conductivity metals like silver and specific inorganic oxides, which are fired to form efficient solar cell electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional conductive paste composition is used, then manufacturing process is simple, but electrical conductivity and adhesion of electrodes are insufficient
Solution Approach 1:
The patent uses a composite glass frit system combining lead oxide (40-70 wt%), bismuth oxide (5-30 wt%), and zinc oxide (5-30 wt%) to achieve optimal electrical conductivity and adhesion. This multi-component composite material resolves the contradiction by providing enhanced performance through synergistic effects of different oxides while maintaining a manageable paste formulation.
Solution Approach 2:
The patent optimizes specific parameter ranges for each component: glass frit (40-70 wt%), metal powder (20-50 wt%), and organic vehicle (10-30 wt%). By precisely controlling these compositional parameters, the invention achieves high electrical conductivity and adhesion without excessive complexity in the paste formulation.
2Reliability
If high conductivity metals are used, then electrical properties improve, but paste viscosity and printability are affected
Solution Approach 1:
The patent balances metal powder content (20-50 wt%) with organic vehicle (10-30 wt%) to maintain optimal paste viscosity for screen printing while ensuring sufficient electrical conductivity. The glass frit composition also contributes to viscosity control through its melting characteristics during firing.
Solution Approach 2:
The organic vehicle acts as an intermediary that enables proper paste flow and screen printing performance while the metal powder provides conductivity. The glass frit serves as a intermediary binder that facilitates both printability and subsequent electrode formation during firing, mediating between the conflicting requirements of conductivity and printability.
3Reliability
If paste composition is optimized for conductivity, then electrode performance improves, but manufacturing cost increases
Solution Approach 1:
The patent uses a cost-effective composite glass frit system combining abundant materials like bismuth oxide and zinc oxide with lead oxide, replacing more expensive single-component systems. The metal powder composition (silver, aluminum, or their alloys) is optimized to balance conductivity performance with material cost, achieving high electrode performance at reasonable cost.
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 significantly improves the electrical properties and adhesion of solar cell electrodes, resulting in enhanced photoelectric conversion efficiency and fine line width printability, while maintaining low contact resistance and stability.
Implementation Method 1
firing the applied conductive paste to form an electrode
Data Source
AI summary
A conductive paste used for a solar cell electrode comprising, (i) 60 wt % to 95 wt % of a conductive powder; (ii) 0.1 wt % to 5.0 wt % of a lead-tellurium-oxide powder, comprising 20 wt % to 60 wt % of PbO and 20 wt % to 60 wt % of TeO2 based on the total weight of the lead-tellurium-oxide powder; (iii) 3 wt % to 38 wt % of an organic medium; and (iv) 0.1 wt % to 1.5 wt % of an inorganic oxide powder selected from the group consisting of Ho2O3, La2O3, Sm2O3, Y2O3, Yb2O3, Gd2O3 and a mixture thereof, based on the total weight of the conductive paste.