Solar Cell Electrode Fine Line Formation via Conductive Paste
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Solution Overview
Problem
Solar cell electrodes formed on the front light-receiving side of crystalline silicon wafers reduce light absorption, and existing methods do not effectively form fine electrode lines to maximize light reception.
Innovation Solution
A conductive paste comprising a conductive powder, glass frit, an organic polymer with an elastomer, and an organic solvent is applied to the semiconductor substrate, allowing for the formation of fine line electrodes through firing, which enhances electrical conductivity and adhesion while minimizing light obstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional conductive paste is used to form solar cell electrodes, then electrical conductivity is achieved, but the electrode lines are too wide which reduces light receiving area
Solution Approach 1:
The patent changes the chemical composition parameters of the conductive paste by incorporating specific organic polymers (ethyl cellulose, carboxymethyl cellulose, hydroxypropyl cellulose) and controlling the metal powder particle size distribution (D10: 0.5-2μm, D50: 2-5μm, D90: 5-10μm). These parameter changes enable the paste to form finer electrode lines with better flow characteristics during firing, achieving narrower line widths while maintaining electrical conductivity.
Solution Approach 2:
The patent uses a composite conductive paste formulation combining multiple components: metal powders (silver, aluminum), glass frit, and specific organic polymers (ethyl cellulose, carboxymethyl cellulose, hydroxypropyl cellulose). This composite material structure provides both the electrical conductivity needed for electrode function and the rheological properties required to form fine lines during the printing and firing process.
2Productivity
If electrode lines are made narrower to increase light receiving area, then light absorption improves, but manufacturing difficulty increases
Solution Approach 1:
The patent modifies the paste formulation parameters including organic polymer content (5-20 wt%), glass frit content (10-30 wt%), and metal powder particle size distribution. These parameter adjustments optimize the paste's viscosity and flow characteristics, enabling it to self-align and form uniform fine lines during screen printing without requiring advanced manufacturing equipment or complex process controls.
Solution Approach 2:
The conductive paste is formulated to exhibit self-aligning properties during the printing and firing process. The organic polymers and glass frit create a paste that naturally flows and distributes itself into uniform fine lines on the semiconductor substrate, reducing the need for precise manual control or complex manufacturing equipment while achieving consistent narrow line widths.
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 method enables the creation of narrow, efficient solar cell electrodes that improve light absorption and electrical conductivity, leading to enhanced solar cell performance without damaging the substrate during the firing process.
Implementation Method 1
an organic polymer comprising an elastomer
Implementation Method 2
firing the applied conductive paste
Data Source
AI summary
A method of manufacturing a solar cell electrode comprising steps of: preparing a semiconductor substrate, applying a conductive paste onto the light receiving side of the semiconductor substrate, wherein the conductive paste comprises (i) a conductive powder, (ii) a glass frit, (iii) an organic polymer comprising an elastomer and (iv) an organic solvent; and firing the applied conductive paste.