IBC Solar Cell Insulation Layout for Short-Circuit-Free Welding
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Solution Overview
Problem
Interdigitated back contact (IBC) solar cells are prone to short circuits during the welding process due to the close arrangement of positive and negative metal electrodes around busbars and welding points, leading to potential electrical connections between fingers and busbars with opposite polarities.
Innovation Solution
The implementation of insulation structures covering areas near busbars and welding points, with specific dimensions and configurations to prevent direct contact between welding strips and fingers, while maintaining open windows for welding and reducing the amount of insulation material needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple first electrodes and multiple second electrodes are arranged in an interdigitated pattern on the rear surface of the solar cell, then the electrical connection efficiency is improved, but the risk of short circuit during welding increases
Solution Approach 1:
The patent introduces insulation structures as intermediary elements between the closely arranged first and second electrodes. These insulation structures physically separate the electrodes with opposite polarities, preventing direct contact and short circuits during the welding process, while still allowing the electrodes to maintain their interdigitated configuration for efficient electrical connection.
Solution Approach 2:
The insulation structures are segmented to cover specific critical areas where short circuits are most likely to occur, such as near busbars and welding points. This selective segmentation provides targeted protection without unnecessarily insulating entire electrode surfaces, thereby maintaining electrical connection efficiency while preventing short circuits.
2Reliability
If insulation structures cover areas near busbars and welding points, then short circuit prevention is improved, but the amount of insulation material increases
Solution Approach 1:
The insulation structures are applied selectively to specific local areas where short circuit risks are highest, such as regions near busbars and welding points. This local quality approach ensures that insulation material is used only where necessary for short circuit prevention, rather than covering entire electrode surfaces, thereby minimizing material consumption while maintaining effective protection.
Solution Approach 2:
The patent employs partial insulation coverage rather than complete insulation of all electrode areas. By applying insulation structures only to critical regions where short circuits are most likely to occur, the solution achieves sufficient short circuit prevention without the excessive use of insulation material that would result from complete coverage.
3Reliability
If insulation structures are added to cover electrode areas, then short circuit risk is reduced, but light transmittance is affected
Solution Approach 1:
The insulation structures are positioned and dimensioned to cover only the specific areas where short circuit prevention is needed, such as near busbars and welding points. This localized approach minimizes the total surface area covered by insulation material, thereby reducing the impact on light transmittance while still providing effective short circuit protection in critical regions.
Solution Approach 2:
The patent uses partial insulation coverage rather than complete insulation of electrode surfaces. By limiting insulation application to only the areas necessary for short circuit prevention, the solution achieves adequate reliability improvement while minimizing the negative impact on light transmittance that would occur with more extensive insulation coverage.
Data Source
AI summary
A first surface of the solar cell has multiple first electrodes and multiple second electrodes staggered in an interdigitated pattern. Each of the multiple first electrodes has a first busbar and multiple first fingers, and each of the multiple second electrodes has a second busbar and multiple second fingers extending along the second direct. A first welding point is defined on the first busbar, and a second welding point is defined on the second busbar. The solar cell further includes multiple insulation structures. Each of the multiple insulation structures extends to cover ends of the multiple first fingers. A window is opened on a projection of at least one of the first busbar and the first welding point on a respective insulation structure, and/or a window is opened on a projection of at least one of the second busbar and the second welding point on the respective insulation structure.