Al Paste with ZrC for PERC Solar Cell Back Electrode
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Solution Overview
Problem
Existing solar cell manufacturing methods for Passivated Emitter and Rear Cell (PERC) type solar cells do not achieve high conversion efficiency due to limitations in the back side electrode formation process.
Innovation Solution
A method involving a semiconductor substrate with a passivation layer on the back side, where an aluminum (Al) conductor pattern is formed using an Al paste containing Al powder, glass frit, zirconium carbide (ZrC) powder, and an organic medium, and then fired to create an efficient back side electrode, which locally connects to the semiconductor layer and includes zirconium carbide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional Al paste containing Al powder, Pb-Si-B glass frit, and organic medium is used to form the back side electrode, then the manufacturing process is simple, but the conversion efficiency of the solar cell is insufficient
Solution Approach 1:
The patent applies composite materials by incorporating ZrC powder into the Al paste formulation. This creates a multi-component paste consisting of Al powder, Pb-Si-B glass frit, ZrC powder, and organic medium. The ZrC particles serve as nucleation sites that enhance the electrical properties of the fired electrode while maintaining the structural integrity provided by the glass frit matrix, thereby improving conversion efficiency without complicating the manufacturing process
Solution Approach 2:
The patent modifies the chemical composition parameters of the Al paste by adding ZrC powder at specific concentrations (0.1-5 wt%). This parameter change alters the firing behavior and electrical properties of the resulting electrode. The ZrC addition changes the paste's reactivity, melting characteristics, and final electrode conductivity, enabling higher conversion efficiency while keeping the manufacturing process unchanged
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 method enhances the electrical properties of the solar cell, leading to improved conversion efficiency and reduced recombination of holes and electrons near the back side surface, while maintaining the passivation effect of the passivation layer.
Implementation Method 1
an Al paste comprising an Al powder, a Pb—Si—B containing glass frit, a zirconium carbide (ZrC) powder, and an organic medium
Implementation Method 2
firing the Al conductor pattern
Data Source
AI summary
A method of manufacturing a solar cell comprising steps of: (a) preparing a substrate comprising a semiconductor layer and a passivation layer formed at least on the back side of the semiconductor layer, wherein the passivation layer on the back side comprises one or more openings; (b) forming an aluminum (Al) conductor pattern at least in the openings of the passivation layer on the back side by applying an Al paste, wherein the Al paste comprises: (i) an Al powder, (ii) a glass frit, (iii) a zirconium carbide (ZrC) powder, and (iv) an organic medium; and (c) firing the Al conductor pattern.