Solar Cell Module Conductive Adhesive for Low Contact Resistance
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Solution Overview
Problem
The existing solar cell module technologies face challenges in ensuring strong adhesive strength and low contact resistance between interconnectors and electrodes, leading to potential short circuits and reduced efficiency due to differences in metal materials used for these components.
Innovation Solution
The use of conductive adhesives made from the same metal material as the interconnectors and electrodes, along with a solder layer or metal alloy, ensures a strong bond and minimizes thermal expansion issues, while an auxiliary metal layer on the interconnectors further enhances connectivity and reduces resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If different metal materials are used for interconnectors and electrodes, then manufacturing flexibility is improved, but adhesive strength and contact resistance deteriorate
Solution Approach 1:
A conductive adhesive layer is introduced as an intermediary between the interconnector and the electrode. This adhesive layer contains metal particles that are the same material as the electrode, creating a gradual transition from the interconnector metal to the electrode metal, thereby improving adhesive strength and reducing contact resistance while still allowing different materials to be used for manufacturing flexibility
Solution Approach 2:
The conductive adhesive is formulated as a composite material containing metal particles (same as electrode material) dispersed in a resin matrix. This composite structure combines the benefits of different metal materials for manufacturing flexibility while the metal particles provide strong adhesive bonding and low contact resistance to the electrode
2Adaptability or versatility
If metal materials with different thermal expansion coefficients are used, then material selection flexibility is improved, but thermal stress and crack formation worsen
Solution Approach 1:
The conductive adhesive's resin matrix is selected to have thermal expansion characteristics that bridge the gap between the interconnector and electrode metals. By carefully choosing the resin type and metal particle content, the composite adhesive's effective thermal expansion coefficient is adjusted to reduce thermal stress during temperature cycles, preventing crack formation while maintaining material selection flexibility
3Reliability
If conductive adhesive with same metal material as electrode is used, then adhesive strength and contact resistance are improved, but manufacturing complexity increases
Solution Approach 1:
The conductive adhesive serves multiple functions simultaneously: it provides mechanical bonding between interconnector and electrode, establishes electrical contact with low resistance, and compensates for thermal expansion differences. This multi-functionality is achieved through a single material formulation, reducing the need for separate layers or components and simplifying the overall manufacturing process despite the improved performance requirements
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 prevents cracks and degradation, maintaining high adhesive strength and contact resistance, thereby enhancing the solar cell module's efficiency and reliability by ensuring proper electrical connection and minimizing short circuits.
Implementation Method 1
a conductive adhesive configured to attach the interconnectors to the first electrodes or the second electrodes
Implementation Method 2
a conductive adhesive configured to attach the interconnectors to the first electrodes or the second electrodes, wherein the conductive adhesive includes the same material or the same metal-based material as a metal material included in at least one of the interconnectors or the first and second electrodes
Data Source
AI summary
A solar cell module is disclosed. The solar cell module includes a plurality of solar cells each including a semiconductor substrate, in which a p-n junction is formed, and a plurality of first and second electrodes which are formed on a back surface of the semiconductor substrate and are separated from each other, a plurality of interconnectors which are connected to the first electrodes or the second electrodes included in each solar cell and connect the plurality of solar cells in series, and a conductive adhesive attaching the interconnectors to the first electrodes or the second electrodes. The conductive adhesive includes the same material or the same metal-based material as a metal material included in at least one of the interconnectors or the first and second electrodes.