Solar Cell Electrode Paste for Low-Temperature Wiring Attachment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing methods for manufacturing solar cell panels face challenges in simplifying the manufacturing process and reducing electrical resistance, particularly with back electrode structures, where adhesion between printing layers and solder paste is poor, and high-temperature processes can damage the cells or alter their characteristics.
Innovation Solution
A method involving a paste composed of metal particles, a solder material, and an adhesive material is used to form a connection electrode portion, which includes a tin-silver-copper alloy and a flux, applied with a heat treatment at 180° C to 280° C, forming an intermetallic compound layer for low resistance and improved adhesion, eliminating the need for a separate solder paste layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrode includes a sputtering layer and a printing layer positioned on the sputtering layer, then the electrical resistance is reduced, but the adhesion characteristics between the printing layer and the solder paste deteriorate
Solution Approach 1:
The patent combines the sputtering layer and printing layer into a single integrated electrode structure formed by printing conductive paste directly onto the solar cell. This eliminates the interface between separate layers that causes adhesion problems, while maintaining low electrical resistance through the continuous conductive path provided by the printed electrode pattern.
Solution Approach 2:
The conductive paste used in the printed electrode contains a composite formulation with metal particles (such as silver, aluminum, or copper) dispersed in a glass frit matrix. This composite material provides both the low electrical resistance needed for efficient current collection and the adhesion properties required for strong bonding to the solar cell and solder paste.
2Device complexity
If the electrode includes only the printing layer, then the manufacturing process is simplified, but high-temperature heat treatment is necessary which can damage the solar cell
Solution Approach 1:
The patent modifies the firing temperature parameter from conventional high temperatures (700-900°C) to a lower temperature range (150-300°C). This parameter change allows the printed electrode to achieve proper adhesion and electrical conductivity without exposing the solar cell to damaging high temperatures that could alter cell characteristics or cause structural damage.
Solution Approach 2:
The conductive paste formulation uses materials that can achieve their functional properties at lower temperatures, replacing the need for high-temperature processing. The glass frit and metal particle composite is designed to sinter and adhere effectively in the lower temperature range, eliminating the requirement for high-temperature heat treatment that risks cell damage.
3Device complexity
If the electrode includes only the sputtering layer, then the manufacturing process is simplified, but the electrical resistance increases due to insufficient thickness
Solution Approach 1:
The patent changes the electrode formation method from thin-film sputtering to thick-film printing, allowing the electrode to achieve sufficient thickness (typically 5-20 micrometers) for low electrical resistance. The printing process deposits a volumetric paste that can be much thicker than sputtered films while maintaining good adhesion and electrical conductivity through the metal particle network.
4Reliability
If the electrode is formed using a plating process, then the electrical resistance is reduced, but the solar cell characteristics are changed or damaged due to plating solution
Solution Approach 1:
The patent replaces the chemical plating process with a printing process that deposits conductive paste directly onto the solar cell. This substitution eliminates the need for plating solutions and their associated harmful chemicals, while still achieving low electrical resistance through the printed conductive pattern. The printing process is non-invasive and does not require chemical etching or deposition that could damage the cell.
Solution Approach 2:
The conductive paste serves as an intermediary material that provides the low electrical resistance function previously achieved by plating, without requiring direct contact with harmful plating solutions. The paste formulation includes adhesion promoters and conductive particles that work together to create a reliable, low-resistance electrode pattern without the need for chemical plating baths.
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 results in a solar cell panel with reduced electrical resistance, improved efficiency, and simplified manufacturing by enhancing the electrode structure for wiring attachment, while preventing damage and maintaining cell characteristics.
Implementation Method 1
forming an intermetallic compound layer for low resistance and improved adhesion
Implementation Method 2
applied with a heat treatment at 180° C to 280° C
Implementation Method 3
an adhesive material
Implementation Method 4
a paste for solar cell electrode comprising metal particles including a first metal, a solder material including a second metal different from the first metal, and an adhesive material
Data Source
AI summary
In a method for manufacturing a solar cell panel according to an embodiment of the present invention, a step of forming an electrode comprises the steps of: forming a main electrode part on a conductive region; and forming a connection electrode part on the main electrode part by using a paste comprising metal particles having a first metal, a solder material having a second metal different from the first metal, and an adhesive material.