Copper Core-Shell Solar Cell Paste for Low-Resistance Contacts
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The high cost of silver paste in solar cell manufacturing and the incompatibility of copper paste due to oxidation at high temperatures hinder the development of cost-effective and efficient TOPCon solar cells.
Innovation Solution
A manufacturing method for solar cells using a conductive paste comprising core-shell particles with a copper core and a protective shell, glass frit, adhesive resin, and solvent, combined with a laser-enhanced contact optimization process, to form electrodes at lower temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silver paste is used to form electrodes in solar cells, then electrical conductivity and contact resistance are improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive silver paste with a cheaper conductive paste formulation containing copper particles, glass frit, and organic vehicle. This substitution directly addresses the cost issue while maintaining functional performance through the synergistic combination of materials that provide both conductivity and processability at lower temperatures.
Solution Approach 2:
The conductive paste is formulated as a composite material system comprising copper particles (for conductivity), glass frit (for adhesion and sintering aid), and organic vehicle (for rheology control). This composite approach enables the paste to achieve both low cost and high electrical performance, resolving the contradiction between material expense and electrical functionality.
2Ease of manufacture
If copper paste is used to replace silver paste, then manufacturing cost is reduced, but contact resistance increases due to oxidation at high temperatures
Solution Approach 1:
The patent fundamentally changes the processing temperature parameter from conventional high-temperature sintering (700-900°C) to low-temperature processing (300-700°C). This parameter change prevents copper oxidation while maintaining good contact resistance, as the lower processing temperature avoids the oxidation issue that plagues conventional copper-based pastes.
Solution Approach 2:
The patent creates an effectively inert processing environment by using a specially formulated organic vehicle that decomposes in a controlled manner during low-temperature sintering, protecting the copper particles from oxidation. The glass frit component also contributes to creating a protective atmosphere during the sintering process, preventing copper oxidation without requiring external inert gas environments.
3Ease of manufacture
If high-temperature processing is used to form metal ohmic contacts, then contact formation is achieved, but copper oxidation occurs and contact resistance increases
Solution Approach 1:
The patent changes the temperature parameter from high-temperature (700-900°C) to low-temperature (300-700°C) processing. This parameter modification enables contact formation while avoiding copper oxidation, as the lower temperature range is below the threshold where rapid copper oxidation occurs in atmospheric conditions.
Solution Approach 2:
The organic vehicle and glass frit act as intermediary substances that facilitate contact formation at low temperatures. The organic vehicle provides a matrix that holds copper particles in position and promotes their sintering, while the glass frit acts as a flux that lowers the sintering temperature and creates a protective environment, preventing direct copper oxidation during the contact formation process.
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 reduces manufacturing costs and improves electrical characteristics by minimizing contact resistance and maintaining stability at high temperatures.
Implementation Method 1
performing a laser opening process to form an opening
Implementation Method 2
performing a firing process
Implementation Method 3
performing a laser-enhanced contact optimization process
Data Source
AI summary
A manufacturing method for a solar cell includes the following steps. The manufacturing method includes providing a solar cell semi-finished product. The manufacturing method includes performing a laser opening process to form openings. The manufacturing method includes forming a conductive paste in the openings. The manufacturing method includes performing a firing process. The manufacturing method includes performing a laser-enhanced contact optimization process. The openings expose the semiconductor doping layer of the solar cell semi-finished product. The conductive paste includes 80 to 120 parts by weight of core-shell particles, 0.1 to 14 parts by weight of glass frit, 5 to 25 parts by weight of adhesive resin, and 5 to 30 parts by weight of solvent. Each of the core-shell particles includes a core and a shell layer, and the core includes copper.