Solar Cell Module Interconnector Design for Thermal Stress Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing solar cell module technologies face challenges in efficiently connecting solar cells while minimizing thermal expansion stress and maximizing optical gain, often resulting in reduced efficiency and increased manufacturing costs due to direct electrode formation on the semiconductor substrate, which can lead to fractures and cracks.
Innovation Solution
The solution involves forming first and second auxiliary electrodes on the back surface of solar cells with conductive adhesives, using an interconnector with different materials and configurations, and positioning it away from the semiconductor substrate to reduce thermal stress and enhance optical gain, while also employing a zigzag interconnector shape for thermal expansion compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrodes are directly formed on the light receiving surface of the silicon substrate, then electrical connection is achieved, but thermal expansion stress increases causing fractures and cracks
Solution Approach 1:
The invention extracts the electrodes from the light receiving surface and relocates them to the back surface of the silicon substrate. This is achieved by forming auxiliary electrodes on the back surface that are electrically connected to the main electrodes, allowing the light receiving surface to remain free of electrodes and thus avoiding thermal expansion stress and substrate fractures.
Solution Approach 2:
The invention transitions the electrode configuration from a two-dimensional planar arrangement on the light receiving surface to a three-dimensional configuration where auxiliary electrodes are formed on the back surface and extend upward to connect with the main electrodes. This spatial reconfiguration reduces thermal stress while maintaining electrical functionality.
2Volume of moving object
If interconnector is positioned close to semiconductor substrate for compact design, then device size is reduced, but thermal expansion stress increases
Solution Approach 1:
The invention introduces auxiliary electrodes as intermediary elements between the interconnector and the semiconductor substrate. These auxiliary electrodes are positioned on the back surface and extend upward to connect with the main electrodes, serving as a mediator that transmits electrical connection while maintaining spatial separation between the interconnector and the substrate to reduce thermal expansion stress.
3Reliability
If electrodes are formed on light receiving surface, then electrical connection is established, but optical gain is reduced due to light blocking
Solution Approach 1:
The invention extracts the electrodes from the light receiving surface and relocates them to the back surface of the silicon substrate. The auxiliary electrodes formed on the back surface extend upward to connect with the main electrodes, ensuring that the light receiving surface remains free of electrode obstructions and thus maximizing optical gain while maintaining electrical connection functionality.
4Ease of manufacture
If conventional module technology is used for connecting solar cells, then manufacturing process is established, but efficiency is reduced and manufacturing costs increase
Solution Approach 1:
The invention performs preliminary action by forming auxiliary electrodes on the back surface of the silicon substrate during the cell manufacturing process, before module assembly. This preliminary configuration of electrodes on the back surface enables more efficient module assembly with reduced thermal stress and improved optical gain, thereby increasing overall module efficiency while maintaining 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 improves the efficiency of solar cell modules by reducing thermal expansion stress, minimizing fractures, and increasing optical gain, thereby enhancing the process yield and reducing manufacturing costs.
Implementation Method 1
The interconnector is connected to the first and second auxiliary electrodes of the first and second solar cells using a conductive adhesive
Implementation Method 2
employing a zigzag interconnector shape for thermal expansion compensation
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A solar cell module is disclosed, which includes a first solar cell and a second solar cell each including a plurality of first electrodes formed on a back surface of a semiconductor substrate, a plurality of second electrodes which are formed in parallel with the plurality of first electrodes on the back surface of the semiconductor substrate, a first auxiliary electrode connected to the plurality of first electrodes, and a second auxiliary electrode connected to the plurality of second electrodes, and an interconnector for electrically connecting the first auxiliary electrode of the first solar cell to the second auxiliary electrode of the second solar cell.