Silver Copper Nickel Solar Cell Electrodes for Warping and Contact
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Solution Overview
Problem
The poor quality of ohmic contact between silicon semiconductor substrates and silver electrodes, along with differences in thermal expansion coefficients between silicon and aluminum, lead to inefficient carrier extraction and warping of the semiconductor substrate, reducing the reliability and efficiency of solar cell elements.
Innovation Solution
A solar cell element with a semiconductor substrate having a first and second semiconductor layer of opposite conductivity types, where electrodes containing silver, copper, and nickel are used, with the second semiconductor layer on the main surface and electrodes formed by coating and firing a conductive paste with a copper-nickel alloy and silver, alleviating stress and improving contact quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If silver electrodes are used on silicon semiconductor substrates, then electrical conductivity is improved, but ohmic contact quality deteriorates and carrier extraction efficiency decreases
Solution Approach 1:
The patent uses a composite electrode structure consisting of multiple metal layers (silver, copper, nickel, and aluminum in specific combinations) rather than pure silver. This composite structure maintains high electrical conductivity while improving ohmic contact quality with the silicon semiconductor substrate, resolving the contradiction between conductivity and contact quality.
Solution Approach 2:
The patent changes the material composition parameters of the electrode by introducing copper and nickel as additional components alongside silver. This parameter change modifies the electrical and mechanical properties of the electrode, enabling both high conductivity and good ohmic contact with the semiconductor substrate.
2Power
If aluminum collector electrode is used on silicon substrate, then carrier collection is improved, but thermal expansion stress increases causing substrate warping
Solution Approach 1:
The patent employs a composite electrode structure where aluminum is combined with other metals (silver, copper, nickel) in specific layers. This composite structure reduces the overall thermal expansion coefficient mismatch with silicon compared to pure aluminum, thereby reducing warping while maintaining carrier collection efficiency.
Solution Approach 2:
The patent applies different metal materials to different regions and layers of the electrode structure. Aluminum is used in specific layers for carrier collection, while other metals are used in adjacent layers to compensate for thermal expansion differences, creating a locally optimized structure that addresses both carrier collection and substrate stability.
3Reliability
If multiple metal layers are added to improve contact quality, then ohmic contact is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple metal layers (silver, copper, nickel, aluminum) into a single integrated electrode assembly that functions as one unified component. This merging approach improves ohmic contact quality through the multi-layer structure while avoiding the complexity of separate, independently managed components.
Solution Approach 2:
The electrode is designed as a composite material structure where multiple metals are combined in specific layers. This composite approach achieves superior electrical contact properties while the layered configuration allows for systematic manufacturing, balancing performance improvement with manufacturing feasibility.
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 configuration enables efficient carrier extraction and prevents warping of the semiconductor substrate, enhancing the reliability and photovoltaic conversion efficiency of the solar cell element.
Implementation Method 1
at least one of the first electrode and the second electrode is formed by coating an electrically conductive paste containing silver, copper, and nickel as the main components, and then firing the electrically conductive paste
Implementation Method 2
the difference in coefficients of thermal expansion between the semiconductor substrate of silicon or the like and aluminum and the difference in coefficients of thermal expansion between aluminum and silver cause stress to occur
Data Source
AI summary
A solar cell element is disclosed. The solar cell element comprises a semiconductor substrate and electrodes. The semiconductor substrate with a first and second main surface comprises a body and a first layer. The electrodes comprise first electrodes on the first layer and second electrodes on the second main surface. At least one of the first electrodes and the second electrodes comprises silver, copper and nickel as a main component. A method for manufacturing a solar cell element is disclosed. An electrically conductive paste containing silver, copper and nickel is prepared. The electrically conductive paste is applied on the semiconductor substrate. The electrically conductive paste is fired to form the solar cell element.